vol 1: rehab - HUD User

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1 VOL I REHAB THE GUIDE FOUNDATIONS

2 DISCLAIMER ThestatementsandconclusionscontainedinthisreportarethoseofStevenWinterAssociates,Inc.and donotnecessarilyreecttheviewsoftheDepartmentofHousingandUrbanDevelopment.StevenWinter Associates,Inc.hasmadeeveryefforttoverifytheaccuracyandappropriatenessofthereportscontent. However,noguaranteeoftheaccuracyorcompletenessoftheinformationoracceptabilityforcompliance withanyindustrystandardormandatoryrequirementofanycode,law,orregulationiseitherofferedor implied.Theproductslistedinthereportareincludedonlyasexamplesofsomeavailableproducts.No endorsement,recommendation,orevaluationoftheseproductsortheiruseisgivenorimplied.

3 F O U N D AT I O N S VOLUME I OF THE REHAB GUIDE TABLE OF CONTENTS FOREWORD3 1.THEREHABGUIDE:INTRODUCTION4 2.FOUNDATIONDESIGNANDENGINEERING6 3.PERMANENTWOOD& PREFABRICATEDFOUNDATIONS10 4.DRAINAGE14 5.DAMPPROOFING&WATERPROOFING20 6.INSULATION25 7.VENTILATION32 8.SHORING,UNDERPINNING,& REPAIR40 9.CRACKREPAIR,COATINGS,& FINISHES46 APPENDIX:PROFESSIONALASSOCIATIONS&RESEARCHCENTERS52 Preparedfor: U.S.DepartmentofHousing andUrbanDevelopment OfceofPolicyDevelopment andResearch Preparedby: StevenWinterAssociates,Inc. BuildingSystemsConsultants Norwalk,CT ContractDUIOOCOOOOO5956 June1997

4 CREDITS STEVENWINTERASSOCIATES,INC.STAFFMEMBERS WHOWEREINSTRUMENTALINTHEDEVELOPMENTAND PRODUCTIONOFTHISGUIDEBOOKINCLUDE: StevenWinter Principal-in-charge AlexanderGrinnell Projectmanagerandprincipalresearcher MichaelJ.Crosbie,Ph.D.,RA Editor-in-chief RoqueRey Chiefillustrator AdrianTuluca,PeterA.Stratton Projectteammembers U.S.DEPARTMENTOFHOUSINGANDURBANDEVELOPMENT OFFICEOFPOLICYDEVELOPMENTANDRESEARCH,AFFORDABLE HOUSINGRESEARCHANDTECHNOLOGYDIVISION DavidEngel Director NelsonCarbonell Seniorarchitect GUIDEBOOKDESIGN AndrewP.Kner ArtDirector MicheleL.Trombley AssistantArtDirector ElizabethRosen Symbols

5 FOREWORD HousingrehabilitationisanessentialcomponentofanystrategytomeetourNationsneedforaffordable housing. Although the individualized nature of the rehabilitation industry sometimes inhibits the rapid adoptionofleadingedgetechnologies,progressdoesnotrestsolelyuponnewideasandwaysofdoing things.Abreakthroughmaterial,alabor-savingtool,oracost-cuttingtechniqueisvaluableonlyifitis widelyadopted.Suchacceptanceisgainedthroughtheconstructionindustrysknowledgeofthesenew developments. To that end, the Department of Housing and Urban Development has commissioned a set of guidebooksthatwillpresentstate-of-the-arttechniques,materials,andtechnologiesforhousingrehabil itation.Thisvolume,FoundationsistherstofnineguidebooksknowncollectivelyasTheRehabGuide thatwillappearoverthenextfewyears. I am pleased to present this important publication in the hope that itwillbecomeavaluable resourceandwillleadtoaffordable,highqualityrehabilitation,andbetterhousingforallAmericans. AndrewCuomo,Secretary USDepartmentofHousingandUrbanDevelopment 3

6 1 THEREHABGUIDE: F O U N D AT I O N S 1.1 INTRODUCTION Thispublication,TheRehabGuide:Foundations isoneinaseriesofguidebooksproducedbytheU.S. DepartmentofHousingandUrbanDevelopmenttokeepthedesignandconstructionindustryabreastof innovationsandstate-of-the-artpracticesinhomerehabilitation.Asistoooftenthecase,innovativetech niques, materials, technologies, and products are slow to make their way into accepted practice. The RehabGuide seriesisintendedtoacceleratethisprocessbyinformingbuilders,architects,engineers,and otherhousingrehabilitationprofessionalsaboutsuchinnovationsandstate-of-the-artpractices. TheRehabGuide wasalsopromptedbythelackofacomprehensivepublicationtomakethe designandconstructionindustryawareofinnovativeandcost-savingdevelopmentsinhousingrehabilitation. Professionaltrademagazines,conferences,andtradeshowsoffersomedistributionofthisinformation, buttheyarerarelyfocussedexclusivelyonhousingrehabilitation,asthisseriesis,noraretheycompre hensive.Itisevidentthatsuchinnovationswillnotadvanceunlesstheindustryismadeawareofthemand theyaretested. FOCUS OF THE REHAB GUIDE Thefocusofthisseriesisonhousingrehabilitation,whichisdifferentthanhomeimprovement. Rehabilitatemeanstorestoretogoodcondition,notnecessarilytoimprovetoastatethatissignicantly differentthantheoriginal.Thisisaneline,butitdistinguishesthisseriesfromhomeimprovementbooks writtenfortheamateur.TheRehabGuide focusesonbuildingtechnology,materials,components,and techniquesratherthanprojectssuchasaddinganewroom,convertingagarageintoaden,ornishing anattic.NorisTheRehabGuide intendedtobeadiagnostictool;anumberofsuchbooksisalready availabletotheindustry. Thecontentforthisguidebook,Foundations,hasbeengatheredfromprofessionalsinthehous ingrehabilitationeld;manufacturersandsuppliersofinnovativetechnologies,materials,components, tools,andequipment;tradeshows,conferences,reports,andpublicationsconsideringsuchissues;trade organizations;andbuildingresearchcenters.AssistancefromtheRemodelors CounciloftheNational AssociationofHomeBuilders,theNationalAssociationoftheRemodelingIndustry,andtheNationalMulti- HousingCouncilwasalsosolicited. HOWTHEGUIDEISORGANIZED NinevolumeswilleventuallymakeupTheRehabGuideinitsentirety,andtheyarelistedonthe backcoverofthisvolume.Eachoneisdevotedtodistinctelementsofthehouse,andwithineachvolume isarangeofissuesthatarecommontothatelementofhomerehabilitationwork.Thepresentvolume, Foundations,forexample,coverstopicsfromthedesignandengineeringofrehabfoundationsystemsto shoringandrepair,waterproong,crackrepair,drainage,andinsulation.Eachvolumeaddressesawide rangeoftechniques,materials,andtools,andrecommendationsbasedonregionaldifferencesaroundthe country.ThroughoutTheRehabGuide,specialattentionisgiventoissuesrelatedtoenergyefciency, accessibledesign,andsustainability. 4

7 EASILYACCESSIBLEFORMAT TheRehabGuide iswrittenandpresentedinaformatintendedforeasyuse.Thespiralbound volumesopenatsothattheycanbeeasilyphotocopied,andtheycanbeassembledandstoredinasingle three-ringbinder.Withineachvolume,drawings,photos,andothergraphicmaterialssupplementwritten descriptionsofabroadrangeofitems:state-of-the-artandinnovativebuildingtechnology,products,mate- rials, components, construction and management techniques, tools, equipment, softwarevirtually any andallitemsthatmakehousingrehabilitationmoreefcientintermsofcostandtime.Whilethecontent focusesonpresenttechnologiesandtechniquesthatarecurrentlypartofthehouse-buildingindustry,The RehabGuide alsoincludesinformationonmaterials,products,andproceduresfromotherconstruction sectors(suchascommercial,industrial,institutional)thatarerelevanttohousingrehabilitation. Theinformationisorganizedindifferentsectionsaccordingtorehabsubjects,andunderhead ingsthatmakethisbookeasytounderstand.EssentialKnowledgegivesthereaderabasicoverviewof theimportantissuesrelatedtothesectionheading.Next,Techniques,Materials,Toolspresentsstate-of- the-artandinnovativeapproachestoaccomplishingthework.Eachentryisexplainedindetail,including itsadvantagesanddisadvantages.Thismakesiteasyforreaderstocompareapproachesandchoosethe onethatismostapplicabletotheirparticularproject.Bydesign,theTechniques,Materials,Toolssection isanoverview,notadetaileddescriptionofimplementation.FurtherReadingliststhevaluableresources relevanttothesubjectwhichreaderscangotoformoredetailedinformation.Finally,ProductInformation providesnamesandaddressesofmanufacturersofproducts,materials,systems,andcomponentsmentioned inthetextsothatmoreinformationcanbeattained.Byvirtueoftheirbeinglistedhere,suchproductsare notnecessarilybeingrecommended;theirexistenceandavailabilityisbeingbroughttothereadersattention. Newproductsshouldbecarefullyevaluatedintheeldastotheirefcacy.Theproductlistsarenotcom prehensive,andweencouragereaderstobringnewmaterialsandproductstoourattentiontobeincluded inlatereditionsofTheRehabGuide. ANOTEONSOURCES Particularly useful sources of technical information on masonry construction, including the repairofbasements,arepublicationsbytheAmericanConcreteInstitute,thePortlandCementAssociation, andtheNationalConcreteMasonryAssociation.TheInternationalConcreteRepairInstitute,whilelargely focusedoninstitutionalandcommercialprojects(includingmulti-familyhousing),publishesavaluable directoryofproductmanufacturers,contractors,andconsultantstitledWhosWhoinConcreteRepair. Othervaluableanddetailedsourcesofinformationfromthegeneralconstructionindustryinclude technicaltrademagazinessuchasConstructionSpecier andtheConcreteRepairBulletin.Publications relatingmoredirectlytoresidentialconstructionincludethe JournalofLightConstruction,OldHouse Journal,ThisOldHouse,FineHomebuilding,andEnergyDesignUpdate.Valuablesourcesofpublications onfoundationandslabconstructionincludetheNAHBsHomeBuilderPressandBookstoreandtheCanada MortgageandHousingCorporation,whichhasanextensivecatalogofexcellentbooksandarticlesona widerangeofsubjectsonhousingconstructionandrehab.Themostcompleteandcomprehensivebookson foundationsaretheBuildingFoundationDesignHandbook andtheBuildersFoundationHandbook. Both were prepared for the US Department of Energy. While the former publication, prepared by the UndergroundSpaceCenterattheUniversityofMinnesota,isnowoutofprint,thelatter,preparedbytheOak RidgeNationalLaboratory,isavailablefromtheNationalTechnicalInformationService,USDepartmentof Commerce,5285PortRoyalRoad,Springeld,VA22161;7034874650. 5

8 2 F O U N D AT I O N DESIGN& ENGINEERING 2.1 EXISTINGFOUNDATIONOVERVIEW Thegreatmajorityofresidentialfoundationsareeitherconcreteorconcreteblock.Concretedominatesin mostareas,especiallyintheSouth,Southwest,andWest.Concreteblockismorecommonintheindustri alizedstatesoftheNortheastandtheNorthcentralUnitedStates. Foundationsofolderhousesbuiltmorethan60yearsago,particularlythoseinruralareas,are oftenmadeofstone.Withinthelast15yearsprefabricatedfoundationsofpressure-treatedwoodorconcrete have become more popular. Recent foundation developments have included various combinations of expandedpolystyrene(EPS)orextrudedpolystyrene(XPS)andrigidsheathingmaterialsaswellassystems thatcombineconcreteandpolystyreneforms,commonlyreferredtoasinsulatingconcreteformsystems. SuchsystemsarenotcommonlyusedinrehabworkandthusarenotincludedinTheRehabGuide.Detailed information on the different types of insulating forms is available from the Insulating Concrete Forms Association. Buildingcodestypicallyrequirethatnewconstruction,whereitreplacesexistingconstruction, beinstalledinaccordancewithcurrentcodes.Becauseavarietyofcodesregional,state,andmunicipal areinforcethroughouttheU.S.,andthesecodesarenowintheprocessofbeingrevisedandconsoli datedintoasinglecode,itisincumbentupontherehabarchitectandcontractortocarefullyresearchand understandthepertinentcodeissuesastheyrelatetofoundationdesignandconstruction. BuildingcodestypicallyreferencingAmericanConcreteInstitute(ACI)standardssetminimum requirementsforthesize,strength,composition,reinforcement,andinstallationofconcreteandconcrete blockfoundationwallsandfootings.Localbuildinginspectorsrespondingtoconstructionproblemsthey haveencountered,aswellasprevailingpracticeintheirareas,willsometimesrequirethickerormore heavilyreinforcedwallsthanthoserequiredbycodeminimums.However,ifengineeringcalculationsprove otherwise,thinnerwallsorlessreinforcementmaybeallowed.Productionbuildersinmanyareasofthe countryhavehistoricallypreferredtobuildthickerconcreteandconcreteblockfoundationwallswithas littlereinforcementaspossible.Thismeansthatthefootingsandfoundationwallsofmanyexistinghouses areoftenunreinforced,contributing,insomeinstances,tosettlementandcrackingproblems.Whenreplac ingconcretewallsitisimportanttoanalyzethesoilconditionscarefullyandtocomplywithlocalcode requirements,addingreinforcementtocompensateforpoordrainagesoilorsubsurfacewaterconditions. ThedesignofconcretefoundationwallsiswellcoveredbybuildingcodesandtheACIstandards referencedinthecodes,aswellasinpublicationsbythePortlandCementAssociationandtheNational AssociationofHomeBuilders.Thedesignofconcreteblockfoundationwallsislikewisecoveredbybuilding codes,theACIstandardsreferencedinthecodes,aswellaspublicationsbytheNationalConcreteMasonry Association(NCMA). 6

9 FURTHER READING CONCRETE ResidentialConcrete,NationalAssociationofHomeBuildersResearchCenter,1994. BuildingMovementandJoints, EB086,PCA,1982. DesignandControlofConcreteMixtures,EB001,PCA,1994(rev.). FoundationReplacement,GregCasorso,JournalofLightConstruction,Sept.1,1994. GuidetoResidentialCast-in-PlaceConcreteConstruction,ACI332R-84,AmericanConcreteInstitute,1984. ConcreteConstructionHandbook,McGraw-Hill,1993. CONCRETEBLOCK NCMAGuideforHomeOwnersandHomeBuildersonResidentialConcreteMasonryBasementWalls, NationalConcreteMasonryAssociation,1994. ConcreteMasonryHandbookforArchitects,Engineers,andBuilders,PortlandConcreteAssociation,1991. RecommendedPracticeforLayingConcreteBlock,PortlandCementAssociation,1993. HomeownersGuidetoBuildingwithConcrete,BrickandStone, SP038,PCA,1988. DesignofConcreteMasonryFoundationWalls,TEK15-1A,NationalConcreteMasonryAssociation,1994. Strength Design of Reinforced Concrete Masonry Foundation Walls, TEK 15-2A, National Concrete MasonryAssociation,1994. 2.2 BASEMENTFLOORS ESSENTIAL KNOWLEDGE Mosthouseswithbasementsbuiltinthiscenturyhaveconcretebasementoorslabs,typically4inches thick.Anumberoftheseoorsmaybeinpoorrepairduetodeterioration,heavingfromexpansivesoils, orsettlementduetopoorinitialsoilcompactionorwater-relatedsoildisplacement.Intheeventofsevere cracking,spalling,orotherdistress,itmaybeadvisabletoreplacesectionsof,ortheentire,oorslab.Ifthe oorslabisinpoorconditionbutretainssubstantialstructuralintegrity,anewunbondedoorcanbe pouredovertheexistingone.Iftheexistingoorisstructurallysound,butunevenormoderatelydeteri orated,itispossibletopourathin,self-bondingtoppingthatcanprovideasmoothnishthatissuitable asanishedsurfaceoranunderlaymentforoorcoveringssuchastileorcarpet. TECHNIQUES, MATERIALS, TOOLS 1.PROVIDEANEWFLOORSLABORREPLACEAPORTIONOFTHEEXISTINGSLAB. Iftheexistingbasementoorisearth,itmustbeexcavatedtoapointnodeeperthanthebottomofthewall footing.Thesubgradeshouldbepreparedtoprovideuniformsupport.Slabssupportedbyexpansivesoils shouldbedesignedtowithstandoraccommodateswellingandshrinkageofthesubgrade.Aminimumof 4inchesofgravel,crushedstone,orcoursesandshouldbeplacedundertheslab.Wherepossible,thisgran ularbaseshouldcoverthetopofthefootingbyseveralinchessothattheslabcansettlesomewhatwithout beingrestrainedbythefootingwhichcouldleadtocracking.Moistureretarders,usuallypolyethylene 7

10 sheeting,aretypicallyrequiredbycodeorlocalconditionsinareaswithpoordrainingsoilsandhigh watertables,tohelppreventmoisturemigrationthroughtheslab.(Thetermmoistureretarderisused insteadofvaporbarrierforon-gradeorunder-slabconditionsbecausethislayerinhibitsthemigration ofgroundwateraswellasvapor.Truebarriersarerarelyachievedinconventionalconstruction,thus thetermretarderisused).TheACI,however,recommendseliminatingthemoistureretarderwhere localgroundconditionsandcodespermitbecausethepolyethylenesheetretardsthecuringofthebottom surfaceoftheconcreteandcanaggravateslabedgecurling,drying,andplasticshrinkagecrackingprob lems.MoreguidancecanbefoundinthereferencedocumentsinFURTHERREADING. ADVANTAGES:Providesuseable,nishedbasementspace. DISADVANTAGES:Excavationandpouringofnewslabispotentiallycostlyanddifculttoundertakewith- outsufcientaccess. 2.POURANEWFULLYBONDEDFLOORSLABOVERTHEEXISTINGSLAB. Ifthesurfaceoftheexistingslabisclean,sound,andofgoodqualitybutneedstobeleveledtoserveas abaseforanishedoor,a1-to2-inch(orthicker)overlaytoppingcanbepouredontheexistingslab. Conventional,low-slumpconcretecanbeusedwithahighsandcontentandsmallaggregate(maximumsize 3/8 inch)withorwithouttheuseoflatexadmixtures.Inaddition,fast-drying,speciallyformulatedpro prietary portland cement-based thin topping/underlayments are available. These products are often referredtoasself-levelingandareprimarilyusedtoprovidealeveloorsurfaceandtorepairoorsthat havedeterioratedorspalled.Toppingsprovideanishedoorsurface;underlaymentsrequireaoorcov eringmaterialsuchastileorcarpet.Gypsumself-levelingtoppingsworksatisfactorilyintheabsenceof moisture,andarenotnormallyspeciedforbasementslabswheretheremaybemoistureproblems. ADVANTAGES:Arelativelyinexpensiverepairthatcancontributesignicantlytotheappearanceanduseofa basement.Self-levelingmixturesaretypicallyrapid-settinganddesignedtoreduceshrinkageandcracking. DISADVANTAGES:Self-levelingmixturescannotbeusedwherethereisapossibilityofasignicantwater problem.Ingeneral,cracksinthebaseslabcanbeexpectedtobetransmittedthroughthenewslab.Will raisetheoorheightandreduceheadroom. 3.PROVIDEANEWUNBONDEDFLOORSLABOVERTHEEXISTINGSLAB. Whentheexistingoorslabisnotinsuitableconditionfortheapplicationofabondedoverlay,anew unbonded4-inchslabcanbeapplied.Theexistingslabshouldbesweptcleanandbadlywornareasor holesshouldbelledwithacement-sandmortartoprovideareasonablyatbase.Alayerofpolyethylene sheetingservesasabond-breakeraswellasamoistureretarder.Nonstructuralweldedwirereinforcement is typicallyrecommendedtohelpdistributeshrinkagestressesandtominimizethesizeofcracks(rein forcement should be placed at the slab center and have sufcient topping to prevent spalling). Polyethyleneornylonberreinforcementcanalsobeaddedtotheconcretetohelpcontrol(butnotelimi nate)cracks.Inareaswithextremelyexpansivesoilsorexceptionallyhighwatertableadditionalslabrein forcementmaybeadvisable. ADVANTAGES:Apermanentxthatcanaddvaluetothehousewithouttheneedtoremovetheexistingslab. Willactindependentlyoftheexistingslabandmaypreventcracksfromreappearingonthenewsurface. DISADVANTAGES:Moreexpensivethanatopping.Willraisetheoorheight.Mayrequiresignicanttimeto cure,duetouseofnonabsorbtivepolyethylenesheetingundertheslab. FURTHER READING ConcreteSlabSurfaceDefects:Causes,Prevention,Repair,1S177,PortlandCementAssociation,1987. ResidentialConcrete,NationalAssociationofHomeBuildersResearchCenter,1994. GuideforConcreteFloorandSlabConstruction,302.IR,AmericanConcreteInstitute,1996. SlabsOnGrade,CCS-1,AmericanConcreteInstitute,1994. ResurfacingConcreteFloors,IS144,PortlandCementAssociation,1996. 8

11 PRODUCT INFORMATION Therearenumerouscompaniesthatmanufactureself-levelingtoppingsandotherconcreterepairprod ucts.Someofthosewithnationaldistributioninclude: Abatron,Inc.,550195thAvenue,Kenosha,WI53144,8004451754. Ardex,Inc.,1155StoopsFerryRoad,Coraopolis,PA15108,4122644240. DaytonSuperiorCorp.,721RichardStreet,Miamisburg,OH45342,8007453700. HarrisSpecialtyChemicals(ThoroSystemsProducts),10245CenturianParkway,Jacksonville,FL 322560564,8003271570. LarsenProductsCorp.,82641PrestonCourt,Jessup,MD207949680,8006336668. LaticreteInternational,Inc.,OneLaticreteParkNorth,Bethany,CT065243423,8002434788. MasterBuilders,Inc.,23700ChagrinBoulevard,Cleveland,OH44122,8006289990. MaxxonCorp.(formerlyGyp-CreteCorp.)920HamelRoad,Hamel,MN55340,8003567887. WRBonsalCo.,P.O.Box241148,Charlotte,NC28224,8003340784. WRMeadows,Inc.,P.O.Box543,Elgin,IL60121,8003425976. QuickCreteCo.,2987ClairmontRoad,Suite500,Atlanta,GA30329,8002825828. SikaCorp.,P.O.Box297,Lyndhurst,NJ07071,8009337452. SonnebornBuildingProducts,Inc.,889ValleyParkDr.,Shakopee,MN55379,8008280253. StoConcreteRestorationDivision,P.O.Box44609,Atlanta,GA303365609;8005423057. TammsIndustriesCo.,7405ProductionDrive,Mentor,OH44060,8002182667. 2.3 CRAWLSPACEFLOORS ESSENTIAL KNOWLEDGE Manycrawlspacesinolderhousesdonothavepermanent,hard-surfaceoors.Typicallythegroundhas beenleftexposed,frequentlyresultinginexcessivemoisture,odors,vermin,andinsects.Itisdifcultand costlytoplaceconventionalconcreteintheconnedareasofexistingcrawlspaces,andbecausethegrade ofthecrawlspacemayslope,conventionalconcretemixtureswillnotprovideuniformcoverage.Newconcrete mixturesusinglightweightaggregateshavebeenintroducedspecicallyforthisuse. TECHNIQUES, MATERIALS, TOOLS POURACRAWLSPACEFLOORSLABOFLIGHTWEIGHTCONCRETE. A specialty concrete product using Zonolite or Vermiculite aggregate has been developed by FTF CrawlspaceSpecialiststhatcanbepumpedfromlightweightmobilemixingequipmentandquicklyinstalled. Thefastdryingmixturewithaconsistencyofheavyshavingcreamwilladheretoalmostanysurface,includ ing walls.Trowelnishedtoanaveragedepthof3inchesoverapolyethylenemoistureretarder,thismate- rialiscuredforlighttrafcin7days. ADVANTAGES:Canconformtoslopingandirregularsurfaces;lessexpensiveanddisruptivethanconven tionallypumpedconcrete;canbepumpedthroughnarrowopeningsandhardtoreachareas;driesfast; reducesmoistureandsoilgasproblems. DISADVANTAGES:Lightweightconcretecannotsustainheavytrafcorheavyobjects. PRODUCT INFORMATION FTFCrawlspaceSpecialists,FiveMountainDrive,NewMilford,CT,06776,8603501092. 9

12 3 PERMANENTWOOD & P R E FA B R I C AT E D F O U N D AT I O N S 3.1 PERMANENTWOOD FOUNDATIONSYSTEMS ESSENTIAL KNOWLEDGE Permanentwoodfoundationshavebeenusedinover200,000homesoverthepastquarter-century,and offeranalternativetoconcreteormasonrysystems.Inrehabwork,permanentwoodfoundationsmight besuitableifalargesectionofanexistingfoundationwallisdamagedbeyondrepairandmustbereplaced. Theyshouldalsobeusedwhenreplacingdamagedportionsofanexistingpermanentwoodfoundation. Thebasicelementsofpermanentwoodfoundationsincludea2xfootingplaterestingoncrushedstone, ontopofwhicha2by4,2by6,or2by8(dependingonnumberofstories,studspacing,andbackll height)studwallisconstructedandsheathedwithplywood.Allwoodmustbepressure-treatedwitheither AmmoniacalCopperArsenate(ACA),AmmoniacalCopperZincArsenate(ACZA)orChromatedCopper Arsenate(CCA).Allfastenersshouldbegalvanizedorstainless,andtheexterioroftheplywoodsheathing coveredwith6-milpolyethylenesheetingfordrainage. TECHNIQUES, MATERIALS, TOOLS REPLACE PORTION OF EXISTING FOUNDATION WITH PERMANENT WOOD FOUNDATIONSYSTEM. Oncethesourceofdamagehasbeencorrected,thedamagedpartoftheexistingfoundationwallshould beremovedsothatthenewfoundationwallcanmatewiththeexistingwall.Thegroundmustbeexcavated totheleveloftheexistingfootings.Thenewfoundationwallcanbesupportedontreatedwoodfooting platesandcrushedstonefootings(Fig.1),orcanrestontheexistingfootings,iffeasible.Accordingto guidelinesdevelopedbytheSouthernPineCouncil,thenewpermanentwoodfoundationsectionsarecon nectedtotheexistingfoundationusingleadexpansionshieldswith 1/2 inch-diametergalvanizedlagscrews for concrete or masonry foundations. If mating to an existing permanent wood foundation, additional studsmaybeneededintheoldersectiontofastenthenewportionwithlagscrews. ADVANTAGES:Workcanbeconductedincoldweatherthatlimitsconcreteormasonryconstruction,giving moreexibilitytotheconstructionschedule.Permanentwoodfoundationscanbeinstalledwithoutheavy equipmentandinareasoftheexistingbuildingthathavelimitedaccess.Approvedbyallmodelcodeagencies. DISADVANTAGES: Mayrequiresignicantexcavation,dependingonextentoffoundationwalltobereplaced. 10

13 FIGURE1. PERMANENTWOODFOUNDATION FURTHER READING BuildingFoundationDesignHandbook,KenLabsetal.,preparedfortheU.S.Dept.OfEnergybythe UndergroundSpaceCenter,UniversityofMinnesota,1988. PermanentWoodFoundationDesign&ConstructionGuide,SouthernPineCouncil,1995. PermanentWoodFoundations,Sure-WestPublishing,RedDeer,Alberta,Canada. 3.2 PREFABRICATEDFOUNDATIONS ESSENTIAL KNOWLEDGE Thetwomajortypesofprefabricatedfoundationsystemsarestructuralinsulatedpanels(SIPs)andprecast concretepanelsystems.Whilethesesystemsareusedprimarilyfornewhouseconstruction,theymaybe usedtoreplacedamagedsectionsofexistingfoundationwalls.TheSIPfoundationsystemsarevirtuallythe sameindetailasthepanelsusedforwallsandroofs,andofferanadvantageoverprecastsystemsinthat thecomponentscanbeeasilyinstalledbyoneortwopeoplewithoutheavyequipment.Precastconcrete panelsmustbecranedintoplace.Asisthecaseforpermanentwoodfoundationsystems,bothSIPsand precastpanelsystemscanbeinstalledincoldweather,thuspermittingexibilityintheprojectschedule. 11

14 TECHNIQUES, MATERIALS, TOOLS 1. REPLACE DAMAGED FOUNDATION SECTIONS WITH A SIP FOUNDATION SYSTEM. Inconcept,aSIPfoundationsystemisidenticaltoapermanentwoodfoundationsystem(Fig.2).SIPsare commonly4by8feetor4by9feetexpandedpolystyrene(EPS)foamcorepanelswith1/2 inchpressure-preser vativetreated plywoodexteriorsheathingand7/16 inchplywoodororientedstrandboard(OSB)interiorsheath ing.Theinteriorsheathingisnormallyrequiredtobecoveredwitharebarriersuchasgypsumboard,although some recently-developed proprietary coating systems such as AFM Corporations Firenish meet the requirementofa15-minutethermalbarrier.Thegroundmustbeexcavatedtotheleveloftheexistingfoot ings. The SIPs are prefabricated and arrive at the site ready for installation on a 2x footing plate over a crushedstone,gravel,orconcretefooting.TheSIPsmatewiththeexistingfoundationwallwitha2xsplice thatisfastenedwithlagscrewsintotheexistingconcreteormasonrywall. ADVANTAGES: Workcanbeconductedincoldweatherthatlimitsconcreteormasonryconstruction,giving moreexibilitytotheconstructionschedule.SIPsfoundationscanbebuiltwithoutheavyequipmentand inareasoftheexistingbuildingthathavelimitedaccess.SIPdelivergoodthermalperformance. DISADVANTAGES: Standardpanelsizesmaynotaccommodatetheportionofthewalltobereplaced.May requiresiginicantexcavationdependingonextentoffoundationwalltobereplaced. FIGURE2. PANELFOUNDATIONWALL 2. REPLACE DAMAGED FOUNDATION SECTIONS WITH PRECAST CONCRETE PANELSYSTEM. Precastconcretefoundationwalls,madetoorder,canbecranedintoplaceaftertheaffectedsectionof the existing foundation has been excavated and the damaged portion of the wall is removed (Fig. 3). Precastsectionsareboltedtogetherandmaycontainholesornotchesintheribsforplumbingorelectri- 12

15 FIGURE3. PRECASTCONCRETEWALL calconduits.SuperiorWallsofAmericaandKistnerConcreteProducts,Inc.offeraprecaststudwallsystem thatuseslightweightconcretetomakethehandlingofthesectionseasier,butacraneisnecessarytoplace them.Thepanelsaremadewith5,000psiconcreteandthemanufacturersstatethattheyusuallydonot needwaterproong,exceptatthejoints.Insulatedconcretewallsystems,whichareplacedongravelor crushedstonefootings,incorporatevaryingthicknessesofpolystyreneinsulationwithanR-5perinchrat ing.Additionalinsulationcanbeplacedinthecavitybetweenthestuds.Theinsideedgeoftheconcrete studs,whichare24incheson-center,havefactory-installednailerstoacceptanishmaterial.Thestuds alsohavepredrilledholesforplumbingandelectricalconduit.Thepanelscanbeboltedtotheedgeof existingfoundationwalls. ADVANTAGES: Allowsaconcretefoundationwalltobereplacedincoldweather;systemsincludeinsulation andfurringfornishedwalls. DISADVANTAGES: Installationrequiresheavymachinery,suchasacrane,andsignicantexcavation,which maynotbefeasibleinaffectedfoundationwallareaswithlimitedaccess. FURTHER READING PrecastConcreteStudFoundationWall,NewBuildingProducts,NAHBResearchCenter,Vol.2,No.5, August/September1996,p.1. PRODUCT INFORMATION MidwestPanelSystems,P.O.Box38,Blisseld,MI49228,5174864844. SuperiorWallsofAmerica,Ltd.,P.O.Box427,Ephrata,PA17522,8004529255. KistnerConcreteProducts,Inc.8713ReadRoadP.O.Box218EastPembroke,NewYork140560218, 7168942267,www.kistner.com 13

16 4 DRAINAGE 4.1 SURFACEAND SUBSURFACEDRAINAGE ESSENTIAL KNOWLEDGE Poorsurfaceandsubsurfacedrainagecanleadtopondingofwateraroundthehouse,leakageofground waterthroughthebasementorcrawlspacewalls,structuraldamagetothefoundationfromthebuild-upof hydrostatic pressure and the freeze/thaw action of water on the foundation system. Successful drainage requiressurfacewatertobeledawayfrombuildingsbyappropriategrading.Thewatercanbedispersed slowlyoverthelandscapeorledoffsitethroughundergroundgraveldrainagewaysorpiping.Surfacerunoff isusuallynotaprobleminlow-densitydevelopments(onetotwohousesperacre)withporoussoilsand vegetationthatallowswatertopercolateintotheground.Higherdensities,hardsurfacessuchasroofsand pavement,andpoorsoilconditionsnecessitatedrainagesystems.Successfuldrainagerequiresthathouses bebuiltabovesurroundinggroundwatertablesandbeprotectedfromgroundwatermigratingthrough thesoilsadjacenttothefoundation. TECHNIQUES, MATERIALS, TOOLS Themostsuccessfultechniquesforimprovingsurfaceandsubsurfacedrainagearoundfoundationsinclude: 1.GRADEAWAY FROMTHEHOUSE. Groundaroundthefoundationshouldslopeawayaminimumof10percentforadistanceof8to12feet (codesvariouslystateminimumsof4to8.3percentfor6to8feet,whichisnotsufcient,accordingto manyexperts). ADVANTAGES: Easilymonitoredandmaintained,allowsfortheltrationofwater-bornepollutantsfromthe land;rechargesgroundwatertablesandaquifers;anatural-appearingtechniquethatrequireslittleorno maintenance. DISADVANTAGES: Dependingonnaturalslope,site,andsoilconditions,achievingnaturalrunoffmaybe expensiveornotpossible.Maybecostlytoachievedependingontheexistingslopeandcharacterofthe buildingsperimeter. FIGURE1. SITEGRADINGSTRATEGIES 14

17 2.PROVIDEAGROUNDROOFAROUNDTHEPERIMETEROFTHEHOUSE. Thisentailstheplacementofanimperviouslayerofclayorbentoniteundertopsoiladjacenttothefoun dationtoactasagroundroof.Thislayerdirectswaterawayfromthefoundation.Sodinrollformcan actasarelativelyimperviouslayerasitisgrownonclaysoil. ADVANTAGES: Aremedywithanaturalappearance,promotinggooddrainage. DISADVANTAGES: Maybedifcultandcostlytoachievedependingontheslopearoundthehouseandthe amountofearth-movingnecessary. 3.CREATESWALESTOCHANNELWATERAWAY FROMFOUNDATION. Furrowscanbecutintotheexitingslopetoleadsurfacerunoffwaterawayfromthefoundationwalls(Fig.1) ADVANTAGES: Anatural-appearingtechniquethatrequireslittleornomaintenance. DISADVANTAGES: Maybecostlytoachievedependingontheexistingslopeandsizeofperimeter. 4.TERRACESLOPETOREDUCEWATERFLOW. Whereslopesaresteepanddirectedatthefoundationwall,theycanbeterracedtoslowandreducetheow ofwater(Fig.1). ADVANTAGES: Atechniquethatrequireslittleornomaintenance. DISADVANTAGES: Maybecostlytoachievedependingontheheightandcharacterofexistingslope. 5.PROVIDEANDMAINTAINROOFGUTTERSANDLEADERS. Cleanguttersandleaders(downspouts)thatdirectwaterawayfromthefoundationbymeansofleader extensions,splashblocks,orundergrounddrainlinesistherstandmostcost-effectivelineofdefense againstwater-relatedproblems. ADVANTAGES: Relativelylowcosttechniquetosupportgoodfoundationdrainage. DISADVANTAGES: Requiresdiligenceinkeepingguttersandleadersclean;splashblocksinplace. 6.PROVIDETRENCHORSOILSTRIPDRAINS. Trenchorstripdrainsplacedbetweentheslopeandthefoundationcaninterceptandredirecttheowof waterfromuphillslopes(Fig.2and3). ADVANTAGES: Preservesnaturalappearanceofslope. DISADVANTAGES: Canbecostlydependingonsizeofdrains;needtobemonitoredandmaintainedtoprevent siltingandclogging. FIGURE2,3. TRENCHDRAIN STRIPDRAIN 15

18 7.PROVIDEGOODDRAINAGEUNDERBASEMENTWINDOWAREAWAYS. Particularly at low points around the foundation, areaways can ll up with plant material, debris, and water,causingleaksaroundbasementwindows.Keepcleanandwelldrainedwithagravelpitthatextends downtothefoundationdrainorleadsviaadrainpipetoaseparategravel(French)drain. ADVANTAGES: Relativelylowcostandeffective. DISADVANTAGES: Requiresmaintenance. 8.REPLACEBACKFILLADJACENTTOHOUSEWITHFREE-DRAININGMATERIAL. Apossibleremedywhenbackllagainstthehouseisoverlycompactedandnon-pourous. ADVANTAGES: Maybecost-effectiveinsomeinstances,dependingonamountofsoiltobereplaced. DISADVANTAGES: Requiresremovalofshrubandplantmaterial;disruptive.Existingfootingdrainsmay notbeadequatelysizedorfunctioningproperly. FURTHER READING Investigating,Diagnosing&TreatingYourDampBasement,CanadaMortgageandHousingCorp.,1992. StormwaterControltoPreventBasementFlooding, CanadaMortgageandHousingCorp.,March1992. 4.2 FOUNDATIONDRAINAGE ESSENTIAL KNOWLEDGE Wetbasementscanbeanindicationofdrainageproblemsaroundfoundations.Mostcodesrequirethatnew housingwithhabitablebasementshaveanapprovedfoundationdrainagesystem(exceptinlocationswith well-drainedsoils).Housesbuiltwithinthelast40yearsprobablyhavedrainagesystemssimilartocurrent techniques,butmayhaveceasedtoproperlyfunctionduetoblockageorabreachinthesystem.Without theopportunitytoinspectadrainageoutfallordischargepipeforowrate,itisvirtuallyimpossibletodeter- mineactualconditions. TECHNIQUES, MATERIALS, TOOLS Fouroptionstoconsideraftersitedrainageandroofdrainagedeciencieshavebeencorrectedandproblems persistinclude: 1.INSTALLANINTERIORPERIMETERBASEBOARDGUTTERDRAINAGESYSTEM. Aperimeterbaseboarddrainagesystemcanbeplacedontopoftheoorslaborcutintothejunctureof the wall and the oor and concreted in place (Fig. 4). The system picks up water draining from wall cracks, thecoresofconcreteblockwalls,andattheoor/wallintersection,anddirectsittoasump pump.SuchpackagedsystemsincludeWaterGuard byBasementSystems,Inc.,andBasementDe-Watering Systems.Baseboardsystemsshouldbesloped1/8 to1/4 inch/ft.toinduceow. ADVANTAGES: Rangesfromrelativelysimpleandinexpensivetomoderatelyexpensive,dependingonthe systemused.Incombinationwithsump,reduceswaterpenetrationthroughwall/slabjuncture. DISADVANTAGES:Collectsleakage;doesnotremedythewalldampnessordrainageproblemsperse,as thewallsremainmoistandtheexposedperimeterdrainsmaybeconsideredunsightlyinnishedspaces. Doesnoteliminatemoldandmildewthatcanappearonwetwallsandinthegutteritself. 2.INSTALLASUMPPUMP. Asumppumpisusedtolowerthegroundwatertabletoapointbelowthebasementslab.Itisusedwhen 16

19 FIGURE4. INTERIORBASEBOARDDRAINAGESYSTEMS waterproblemspersistandexteriordrainagesystemsarenotpossibleorpracticable.Ifsoilgasessuchas radonormethaneexist,sumppumpsshouldbecoveredandventedtotheoutdoors.Anelaborationofthe sumppumpsolutionistoinstallaradialdrainagepipesystem,suchasthatofferedbySanfordIrrigation, installedundertheslab(Fig.5)thatdirectswatertothesump.Toensuresumpoperationintheeventof apoweroutage,water-drivenemergencyback-uppumps,suchasHomeGuardfromHiLoIndustries, providecontinuousoperationwithaminimumof22psipressurefromamunicipalwatersystem. ADVANTAGES: Leastcostalternativetoloweringthewater-tableandreducingwaterproblemsinthebasement. DISADVANTAGES:Maynotbeadequateifamajorandcontinuousground-waterproblemexists.Sumppump operationisanaddedhouseholdexpense,andmaybedisruptedbypoweroutages. 3.REPLACETHEBASEMENTSLABANDINSTALLINTERIORFOUNDATIONDRAINS. Atechniquetobeusedwhenasumppumpaloneisnotadequate,andwherethegroundbeneaththeoor FIGURE5. INTERIORRADIALSUMPSYSTEMWITHSUMPPUMP slabisrelativelyimperviousandgreaterdrainageareaisrequired.Theexistingslabperimetermustbe removedandnewdrainsinstalled(Fig.6),whichdirectwatertoasumppump. ADVANTAGES: Eliminatestheneedtoremovesoilfromagainsttheoutsideofthefoundationwall,andfrom disturbingthefoundation. DISADVANTAGES:Entailsremovalofatleastportionsoftheexistingslabandpouringanewslab,which maybedifcultandexpensive,basedonaccesstothebasementspace.Mustbecarefullydesignedandbuilt byprofessionalsexperiencedinthesesystems.Maynotworkwithpermanentlyhighgroundwater. 17

20 4.EXCAVATETHEEXTERIORFOUNDATIONWALLANDINSTALLANDREPAIROR REPLACETHEEXISTINGDRAINAGESYSTEM. Soilisremovedfromagainstthebasementfoundationwallandnewdrainagematerialisinstallednextto thewall,whichdivertswatertonew4inches(orlarger)drainagepipesorotherapprovedsystematthe baseofthewall.Inpoorlydrainingsoils,asheetdrainagematerialcanbeusedtoenhancethemovement ofwatertothefoundationdrainandreducehydrostaticpressureagainsttheoutsideofthewall. ADVANTAGES: Withaproperlydrainedfoundationwallthepossibilityofleakagethroughbasementwalls isreducedsignicantlyandinteriorwallnishescanbeappliedwithlessconcernforwaterdamage. DISADVANTAGES:Thisworkrequiresremovaloftheexistingplantmaterialandsoil,whichcanbeexpensive. Solutionmaybecostly,butthebeststrategyforcertaindrainageproblems. Corrugated,exiblepolyethylenepipinghasreplacedconcreteandclayfoundationdrainagepipeasthe industrystandard.Somemanufacturers,suchasHancor,sellanon-wovenlterfabricsockthattsover thedrain.Thismaybesatisfactoryinsomeareas,butwheretherearesignicantnesinthesoilthat migratewithwater,itispreferabletoencasethegravelareaaroundthedraintile,asthegreatersurface FIGURE6. INTERIORFOUNDATIONDRAIN areawillextendthelifeofthelterfabric.Localconditionsandcodesshouldbeconsulted.Considerable interesthasbeengeneratedinwalldrainagesystems,calledsheetorgeocompositedrains,astheyhave beensuccessfullyusedonalargescaleinCanada.Theyareincreasinglyseenasacost-effectiveaddition todamp-proongandwater-proongtechniquesintheUnitedStates,astheyarelessexpensivethancor respondingaggregatedrainagematerial.Therearefourbasictypesofsheetdrainagesystems: 1.Dimpledpolyethyleneorpolystyrenesheetsusedinconjunctionwithalterfabrictoformacontinu ousdrainagechannel.Thematerialisinstalledwiththedimplesandlterfabricawayfromthe wallto assure good adherence to it. The sheets, typically used with a damp-proong or water-proong mem brane,canalsobeusedforunder-slabdrainage.Onemanufacturer,AmericanWickDrainCorp.,offersa sheetdrainthatconnectstothefoundationdrainsystem(Fig.7). 2.Formedpolyethylenesheetswithoutlterfabricthatorientthedimplestowardthewall,providinga continuous 1/4" drainage space (Fig. 8). This system, widely used in Canada, does not require damp- proongtobeappliedtothefoundationwall,andkeepsbackllsoilandmoisturefromrestingagainst thewall.ThesystemissoldunderthenameofSystemPlaton,manufacturedbytheBigOCo. 3.Mattingofvarioustypesthatformsawalldrainagesystemtobeusedwithappliedwater-anddamp- proongsystems.Productsinclude:WARM-N-DRI,a6-pound-densityber-glassmat,usedincombina tionwithasprayedTUFF-N-DRIpolymermodiedasphalt,notonlydrainsthechannelwater,butalso hasanR-ratingofapproximately4perinchwhendry,offeredbyKochMaterialsCo.;RoxulDrainboard, 18

21 FIGURE7,8. AMERICANWICKDRAIN SYSTEMPLATON amineralwoolblanketmanufacturedbyRoxul,Inc.;Enkadraindrainagemattingofgeotextilefabric heatbondedtoathree-dimensionalhigh-densitypolyethylenecore,whichallowswatertoseepintothe corewhileitholdsbackadjacentsoil,manufacturedbyAkzoNobelGeosynthetics. 4.Drainagesystemsusinggroovedextrudedpolystyreneboardstoenhancedrainageagainstfoundation walls.AmongtheseproductsisOwens-CorningsINSUL-DRAIN,whichhasanetworkofdrainagechannels cutintoonesideoftheboardwhichallowsgroundwatertodrainawayfromthefoundationwall.Dows StyrofoamTHERMADRYboardalsohasgroovestoencouragedrainage. FURTHER READING Builders Foundation Handbook, John Carmody, et al., prepared for the U.S. Dept. of Energy by the UndergroundSpaceCenter,UniversityofMinnesota,1991. Investigating, Diagnosing & Treating Your Damp Basement, Canada Mortgage and Housing Corp., 1992. MethodsofConstructingDry,FullyInsulatedBasements,CanadaMortgageandHousingCorp.,1991. PRODUCT INFORMATION WaterGuard byBasementSystems,Inc., P.O.Box160,Canton,IL61520,8003312943. BasementDe-WateringSystems,162EastChestnutStreet,P.O.Box160,Canton,IL61520,8003312943. HomeGuard,HiLoIndustries,P.O.Box16056,Louisville,KY402560056,5027780234. SanfordIrrigation,444EastHighway79,ElbowLake,MN56531;2186854344. AmericanWickDrainCorp.,316WarehouseDrive,Matthews,NC28105,800242WICK. Hancor,Inc.,401OliveStreet,P.O.Box1047,Findlay,OH45839,8005379520. SystemPlaton,BigOInc.,254ThamesRoadEast,Exeter,Ontario,Canada,N0M1S3,8002657622. WARM-N-DRI,KochMaterialsCo.,P.O.Box2155,Heath,OH430561132,8003792768. Drainboard,Roxul,Inc.,551HarropDr.,Milton,Ontario,Canada,L9T3H3,8002656878. Enkadrain,AkzoNobelGeosyntheticsCo.,RidgeeldBusinessCenter,RidgeeldCourt,Suite318, P.O.Box7249,Asheville,NC28802,7046655050. INSUL-DRAIN,Owens-Corning,FiberglassTower,Toledo,OH43659,800GETPINK. StyrofoamTHERMADRY,DowChemicalCo.,2040WillardH.DowCenter,Midland,MI,48674, 8004414369. 19

22 5 DAMPPROOFING& WA T E R P R O O F I N G ESSENTIAL KNOWLEDGE Dampnessinabasementcanrenderitvirtuallyuseless,evenforstorage.Sourcesofmoistureinbasements includetheintrusionofground-waterthroughcracksinwallsandslabsandtheirjunctures,wickingof moisturethroughconcretebycapillaryaction,andtheinltrationofmoistairfromoutside(thislastsource isdiscussedintheVentilationsection).Dampnesscanalsobeahealthhazard.Recentstudiessponsored bytheCanadaMortgageandHousingCorporation(CMHC),HealthCanada,andtheNationalResearch CouncilofCanadaaswellasHarvardUniversityhaveestablishedthatmoisturecanleadtoincreasesina numberofbiologicalcontaminentsincludingmold,dustmites,andbacterialtoxins;someofthemolds producetoxinsthatareharmfultohumans. Buildingcodesgenerallyrequirethatallbelow-gradebasementwallsbedampproofedorwaterproofed. Dampproongisusedintheabsenceofhydrostaticpressureandisintendedtoprotecttheinteriorsurface of foundation walls from water vapor diffusion, caused by temperature/humidity differentials, and the wickingofmoisturethroughthewallbycapillaryaction. Waterproongisdesignedtobridgenonstructuralcracksuptoamaximumof 1/16 inch.Itisrequired whenhydrostaticpressureexistsorislikelytooccurduetothepresenceofgroundwateratelevations abovethebasementslab.Insuchcases,bothoorsandwallshavetobewaterproofedanddesignedto withstandhydrostaticpressure.Waterproongisusuallyappliedfromthetopofthefootingtonotlessthan 12inchesabovethemaximumelevationofthewater-table.Undersomecodes,theremainderofthewall canbedampproofed,butitisusuallybettertocontinuewaterproongallthewaytograderatherthan changingmaterials.Althoughitissubstantiallymoreexpensivethandampproong(sometimesbyafac torof10ormore)waterproongisincreasinglybeingspeciedinlieuofdampproonginmid-tohigh- end housing because of its static, nonstructural crack-spanning capability and because basements, now morecommonlyusedforlivingspace,areexpectedtobedry.Materialsandapplicationsthatcomewith writtenperformanceguaranteesarepreferred. TECHNIQUES, MATERIALS, TOOLS Thereareanumberoftechniquesandmaterialsforeffectivedampproongandwaterproong.Thefollowing alternativesconsiderdampproongrst,andthenwaterproong. DampproongmaterialsforwallsincludethosecomplyingwithASTMC887,materialspermittedforwater- proong,andotherapprovedmaterials.Thereareanumberofapproachestodampproong: 1. APPLY CRYSTALLIZATION PRODUCTS OR CEMENTITIOUS COATINGS TO FOUNDATIONWALLINTERIOR. A variety of coatings are sold as interior (referred to as the negative side) waterproong products, includingsealersandpaints.Someoftheseproductsmayworkintheabsenceofhydrostaticpressure,but mostinteriorcoatingsystemsarenotlong-termsolutionsandwillfailundersustainedpressureandsub- 20

23 stratemovement.ProductssuchasBonsalsSureCoatandThoroSystemsThoroSeal arerepresented as being able to prevent water intrusion even under pressure. Crystallization products such as Xypex, Vandex, and Permaquick combine proprietary chemicals with sand and cement. This slurry produces crystallizationgrowthinconcreteormasonrysubstratesthatllopenporesandisrepresentedasbeingable toblockthepassageofwater. ADVANTAGES:Mayprotecttheinteriorsurfaceofthewallfromwaterwickingfromboththeexteriorwall surfaceandthefoundationbase.Canberelativelyinexpensivesolutions,ascomparedtoexteriorwork; usuallyeasytoapply.Cementitiousandcrystalizationmaterialscanbeappliedtodampconcrete,allowing watervaportopassthrough;non-toxic. DISADVANTAGES:Oftennoteffective,especiallyonactivecracksandthosegreaterthan1/64 inch.Doesnot preventgroundwaterfrompenetratingtheCMUwytheontheexteriorsideandbecomingtrappedinside thewallwhichisaseriousproblemincoldclimates.Finishmaynotbeacceptableandmayrequirepan elingordrywallcovering.Crystallizationproductsarenoteffectiveovercontroljoints. 2.APPLYCEMENTITIOUSCOATINGSTOFOUNDATIONWALLEXTERIOR. Commonlyknownasparging,thesecoatingsareprimarilyusedforconcreteblockwalls.Theyshould becombinedwithacrylicmodiers(madebycompaniessuchasBonsal,ThoroSystemsandSonneborn). ADVANTAGES:Awidelyusedsystemformanyyearsandmaybecost-effectiveinlocationswithgooddraining soils.Protectsfrommoisturewickingfromoutsidethewall.Doesnotrequirecompletelydrysubstrateor protectionboards.Canbecombinedwithpolyesterreinforcingmeshtoenhanceperformance.Non-toxic materials. DISADVANTAGES:Nocrack-spanningcapabilities.Therehavebeencrackingandspallingproblemswith somecementitiouscoatingsovertimeduetowatermigrationbehindthesubstrate,andfreeze/thawcycling. Requiresexcavation. 3.APPLYASPHALTICCOATINGSWITHOUTMODIFIERSTOFOUNDATIONWALL EXTERIOR. Asphalticdampproongproductscomeinavarietyofformulationssolvent-oremulsion-basedwith orwithoutberstogivethembody.Hot-appliedcoatingsarenecessaryincoldweatherwhenemulsion- basedcoatingsmayfreeze.Bothhot-andcold-appliedcoatingshavevaryingconsistenciesandformula tions, allowing them to be troweled, rolled, brushed, or sprayed. Cold-applied coatings are becoming morecommon,andcanbeappliedtoslightlydampsurfaces.Solvent-basedmaterialscannotbeapplied untilconcretehascuredsufcientlytomeetmanufacturersrecommendations. ADVANTAGES:Availableeverywhere,economicalandeasytoinstallwithlittleskill.Cost-effectivewhenserious waterproblemsdonotexist.Usedalmostexclusivelyinmanyregionsforstarterandlow-endhousing. DISADVANTAGES:Materialscanlosetheirlimitedelasticityduetoagingandfreeze/thawcycling.Willnot spancracks.Unattractivewhenexposed.Requiresprotectionboard.Requiresexcavation. 4.APPLYACRYLICOROTHERAPPROVEDPOLYMERSEALERSTOFOUNDATION WALLEXTERIORORSLABSURFACE. Somerecentlydevelopedpolymer-basedmaterialsareavailablethathavemodelcodeapprovalsforuseas dampproong.Oneoftheseproducts,Poly-Wall, isanattractivegray,nonasphalticcoatingthatcanbe paintedtomatchanycolor. ADVANTAGES:Fast-dryingandeasytoapplybyspraying.Canalsobeusedoninterioroffoundationwallto reduceoreliminatemoisturemigrationintheabsenceofhydrostaticpressure.Exteriorusewillqualifyas waterproongwhenusedinconjunctionwithrubberizedasphaltsheetmembraneaccessorycomponent. DISADVANTAGES:Withoutadditionalmembrane,willnotspancracks.Solventbased;requirescuringperi odpriortoapplicationofsealeronnewconcrete.Moreexpensivethanotherdampproongproducts, normallyusedinhigher-endhousing.Requiresexcavation. 5.APPLYPOLYETHYLENESHEETBELOWFLOORSLAB. Generallyrequiredbycodestobenotlessthan6-milthick,withjointslappednotlessthan6inches(12 21

24 inchesispreferred),shouldbesealedwithdouble-sidedasphaltictapesuchasthatmanufacturedbyReef Industries,Inc.priortopourtoassurecontinuityofthebarrier,especiallyinclaysoilswherecapillary actionissevere. Fiber-reinforcedorhigh-densitypolyethyleneshouldbeconsidered.Thesematerialscost alittlemore,butanundamagedbarrieriskeytotheslabsperformance.Dampproongsystemsthatcome withwrittenmaterialandperformancewarrantiesarepreferred. ADVANTAGES:Ifproperlyinstalled,providesacontinuous,imperviousbarriertomoisturemigratingfrom belowtheslab.Canbeinstalledovercrackedslabs,withnewslabpouredontop. DISADVANTAGES:Caremustbetakennottopuncturesheettomaintaingoodperformance. Thereareanumberofapproachestoexterior(positiveside)waterproong.Systemsareusuallyrequired tomeetASTMC-836,whichsetselastomericcharacteristics. 1.APPLYANASPHALTIC-BASEDPRODUCTTOTHEFOUNDATIONWALLEXTERIOR. Thesehot-orcold-appliedproductsaresimilartothoseusedfordampproong,butareusedintwoor morecoatsincombinationwithpolyester,berglassorothertypesoffabricmembranes. ADVANTAGES:Usedextensivelyinthepast,thistechniquehasaprovenrecord.Stillpreferredandeconomi calinsomeregionswhereroongcontractorsusesimilarsystems. DISADVANTAGES:Lessenvironmentallyfriendlythanotherproducts.Doesnotbridgecracksorweatheras well as some other systems. More labor intensive to install than some of the new one-coat products. Requiresbackllprotectionlayer.Hotsystemsaredifculttoapplyonverticalsurfacesduetoweightof fabricmembraneandviscosityofasphalt. 2.APPLYARUBBERIZEDASPHALTCOATINGTOTHEFOUNDATIONWALLEXTERIOR ORSLABSURFACE. Theseproductsoriginatedinpipelineprotectionandcommercialbuildingmarkets,butareincreasingly usedinresidentialprojects.Theyareconsideredhigherperformingthanconventionalasphaltproducts andhavebecomelowerincostinrecentyears.Madeanddistributednationwidebysuchmanufacturers asW.R.Grace,Sonneborn,andKochMaterialsCo. ADVANTAGES:Theseproductsoftencomewithmaterialandperformanceguarantees.Haveexcellentelas tomericqualitiesandcanspanstatic,nonstructuralcracks.Canbespray-appliedorinstalledwithself- adhering rolls that eliminate need for seam adhesive. Sheet material guarantees consistent thickness, unlikesprayapplications.Sprayapplicationsrequirelessskill. DISADVANTAGES: More expensive than non-modied-asphaltic products. Spray applied solvent-based materialsshouldnotbeappliedoverfreshconcrete.Requiresbackllprotectionlayer. 3.APPLYANASPHALT-MODIFIEDURETHANECOATINGTOTHEFOUNDATION WALLEXTERIOR. Asphaltisusedasallerwithurethanetolessenthecostofthematerial,withoutsacricingperformance. Productshavetypicallybeenusedincommercialapplications,butarebecomingmorecommoninresi dentialwork.DistributednationallybySonneborn.Brushorsprayapplied. ADVANTAGES:Goodelongation;warrantiesavailable. DISADVANTAGES:Requirebackllprotectionlayer;moreexpensivethannon-modiedasphaltcoatings. 4.APPLYAURETHANECOATINGSYSTEMTOTHEFOUNDATIONWALLEXTERIOR. Thesesystemshavethehighestelastomericcapabilitiesofuidappliedmembranes.Urethanesystemsare available in one- or two-component materials. Typically black in color, urethanes are solvent-based, requiring substrates to be completely dry to avoid membrane blistering. Available nationally through Karnak,Sonneborn,Mameco,andGACOWestern. ADVANTAGES:Fluid-appliedsystemsareself-ashing,allowingseamlesscoveringofcomplicatedjointsand protrusions.Highperformance,easeofapplication.One-coatsystemsavailable.Goodresistancetochem icalsandalkalineconditionsonmasonrysubstrates.Warrantiesavailable. DISADVANTAGES:Solvent-based.Materialscostcanbeasmuchasthreetimesthatofleastexpensivewater- proongsystems,buteconomicaltoapply.Requiresskilledapplicators. 22

25 5.APPLYARUBBER-BASEDCOATINGTO THEFOUNDATIONWALLEXTERIOR. Anumberofrubber-derivedmaterialsincludingneoprene,butyl,andhypalonareusedinhigh-end waterproongsystems.Thesematerialshaveexcellentelastomericcapabilities,butlessthanthatofurethane. Theyareresistanttomostchemicalslikelytobeencounteredbelowgrade.Sheetmaterialsarealsoavail- able,includingEPDMandbutylsystemswheresignicanthydrostaticpressureisevident.Usedprimarily onhorizontalsurfacessuchasslabs.Mostmanufacturershaveexperienceincommercialapplications, andafewnewwallwaterproongproducts,suchasRub-R-Wall andComposeal havebeendeveloped specicallyforresidentialapplications. ADVANTAGES:Highperformance;resistanttochemicals;warrantiesavailable. DISADVANTAGES:Canbeexpensive;likelytobecosteffectiveonlyinhigh-endhousingorwhenserious foundationwaterproblemsareencountered. Sheetsystemsarenotself-ashingatprotrusionsandchanges inplane.Requiresbackllprotectionlayerandskilledapplicators.Someproductsarehighlyammable andtoxic. 6.APPLYACLAY-BASEDWATERPROOFINGSYSTEMTOTHEFOUNDATIONWALL EXTERIOR. Naturalclaysystems,commonlyreferredtoasbentonite,typicallycontain85to90percentclayanda maximumof15percentnaturalsedimentssuchasvolcanicash.Whenexposedtowater,bentoniteswells 10to15percentaboveitsdryvolumeandbecomesimpervioustowater.Availableinpanels,sheets,andin combinationwithurethane-,rubber-,andasphalt-basedproductstoenhanceperformance.Itisalsoavail- ableinmatformwithatextilebackingsimilartocarpet.Notwidelyusedinresidentialconstruction,but is recommended by some architects and contractors who have used it. A widely distributed product is VolclayWaterproong,manufacturedbyAmericanColloidCo. ADVANTAGES:Excellentwaterproongmaterial;canbeappliedtorecentlypouredconcrete;nottoxicor harmfultotheenvironment;usefulinunderslabwaterproong;minimalsubstratepreparationrequired. DISADVANTAGES:Requirescarefulapplication;hydrationandswellingmustoccurinconnedspaceafter backllingforwaterproongpropertiestobeeffective.Ifspaceistooconned,bentonitecanswellwith enoughforcetoraiseaoorslaborcrackconcrete.Subjecttoprematurehydrationifnotproperlypro tected.Wettinganddryingthematerialwillcauseittoloseitswaterproongproperties.Shouldnotbe installedwherefree-owinggroundwateroccursthatcouldwashclayawayfromsubstrate.Notresistant tochemicals. FURTHER READING Builders Foundation Handbook, John Carmody, et al., prepared for the U.S. Dept. of Energy by the UndergroundSpaceCenter,UniversityofMinnesota,1991. ControlofMoistureProblemsAffectingBiologicalIndoorAirQuality,B.FlanniganandP.R.Morey, InternationalSocietyofIndoorAirQualityandClimate,1996. DevelopmentofanInteriorDampproongStrategytoPreventBasementWallCondensationDuring Curing,CanadaMortgageandHousingCorp.,1994. Investigating, Diagnosing & Treating Your Damp Basement, Canada Mortgage and Housing Corp., 1992. JointsinWallsBelowtheGround, CR059PCA,1982. MethodsofConstructingDry,FullyInsulatedBasements,CanadaMortgageandHousingCorp.,1991. MoistureControlinBuildings,HeinzR.Trtechsel,ed.,AmericanSocietyforTestingandMaterials,1994. MoistureProblems, CanadaMortgageandHousingCorp.,1995. PreventingWetBasements,CTTVol.17No.1PL961,PCA,1996. PreventingWaterPenetrationinBelow-GradeConcreteMasonryWalls,TEK19-3A,NCMA,1994. 23

26 WaterproongtheBuildingEnvelope,MichaelT.Kerbal,McGraw-Hill,1993. PRODUCT INFORMATION W.R.Bonsal,8201ArrowridgeBoulevard.,Charlotte,NC282241148,8003340784. ThoroSeal,ThoroSystemProducts,8570PhillipsHighway,Suite101,Jacksonville,FL322568208, 8003227825. Xypex Chemical Corp., 13731 Mayeld Pl., Richmond, British Columbia, Canada, V6V 2G9, 6042735265. Vandex,P.O.Box1440,Columbia,MD21044,8003941410. PermaquickCorp.,1591TrinityDrive,Mississauga,Ontario,Canada,L5T1K4,9055646100. Sonneborn,ChemRex,Inc.,889ValleyParkDrive,Shakopee,MN55379,8004339517. Poly-WallInternational,1879BuerkleRoad,WhiteBearLake,MN55110,8008463020. GraceConstructionProducts,W.R.Grace&Co.,62WhittemoreAve.,Cambridge,MA 021409901,8003545414. KochMaterialsCo.,P.O.Box2155,Heath,OH430561132,8003792768. KarnakCorp.,330CentralAvenue,Clark,NJ,07066,8005264236. MamecoInternational,4475East175thStreet,Cleveland,OH44128,8003216412 GacoWesternInc.,P.O.Box88698,Seattle,WA981382698,800456GACO. Rub-R-Wall,RubberPolymerCorp.,1135WestPortageTrailExtension,Akron,OH44313, 8008607721. Volclay Waterproong, American Colloid Co., 1500 W. Shure Dr., Arlington Heights, IL 60004,7083924600. ConcreteRestoration,MaterialsandApplicationFieldGuide, STOConcreteRestorationDivision,P.O.Box 44609Atlanta,GA303365609,8005423057. ReefIndustries,Inc./GrifnVaporBarriersP.O.Box750250,Houston,TX772750250,8002316074. 24

27 6 I N S U L AT I O N 6.1 INSULATINGBELOWGRADEWALLS ESSENTIAL KNOWLEDGE Insulationisanimportantelementincontrollingthermalcomfortofbasementspaces.Therearetwobasic approachestoinsulatingexistingconcreteormasonryfoundationwalls:applyinginsulationtotheexterior orinteriorofthewall.Researchhasshownthatthereisnotasignicantdifferenceinenergysavings. Therecentwidespreaduseoffoamplasticinsulationbelowgradehasincreasedawarenessthat foamplasticincontactwiththesoilcanallowundetectedaccessbyinsectsincludingtermitesandcarpenter antsthroughtheinsulationtocellulose(food)materialinthestructureabove.Inresponsetothisproblem, the1997NorthCarolinaStateBuildingCode,VolumeIII-Residential,requiresinspectionandtreatment gapsinexteriorfoundationinsulation.Inaddition,inconstructionwherewoodisusedasastructuralmem ber,the1997StandardBuildingCode andtheproposed1998CABOOneandTwo-FamilyDwellingCode prohibittheuseoffoamplasticsontheexteriorfaceorunderinteriororexteriorfoundationwallsorslab foundationslocatedbelowgradeinareaswheretheprobabilityoftermiteinfestationisveryheavy.Arefer encemapindicatingtheseareasincludesmostofCalifornia,easternTexas,Louisiana,Mississippi,Alabama, Georgia,FloridaandSouthCarolina.ACABOexceptionisbuildingswherethestructuralmembersofwalls, oors,ceilings,androofsareentirelyofnon-combustiblematerialsorpressure-preservative-treatedwood. TECHNIQUES, MATERIALS, TOOLS 1.APPLYEXTERIORINSULATION. Coveringtheupperhalfonlyiscosteffectiveinregionswithlowheatingdegree-day(HDD)requirements (below2,000HDDorinareaswithupto2,400HDDandlowfuelcosts).Coveringtheentirewall(Fig.1) iscost-effectiveatvaryinglevelsofinsulationfromR-10toR-15dependingonregionalfuelcosts. FIGURE1. CONCRETEBASEMENTWALLWITHEXTERIORINSULATION 25

28 ADVANTAGES:Exteriorapplicationscanprovidecontinuousinsulationwithnothermalbridges;protectand maintainwaterproong/dampproongatmoderatetemperatures,therebyextendingitslife;reduceorelimi nateinteriormoisturecondensationproblems,sincethewalliswarm;donotaffectinteriornishesorreduce useableoorarea;willallowinspectionofinteriorwalls,sills,andrimjoistsforinsectinfestationandmold. DISADVANTAGES:Somecodesnowprohibittheuseoforrequirethattheinsulationbediscontinuoussothat insectpathwayscanbedetected.Requiresexcavatingthefoundationwallforinstallation. 2.INTERIORINSULATIONCOVERINGTHEENTIREWALLFROMFLOORTOCEILING. Insulationisappliedtotheinteriorwallsurface,eitherasrigidinsulationboardincombinationwithfurring stripstoreceivedrywallorpanelingandaccommodateelectricalwiring,orinbattformbetweenfurring studs.DowChemicalandOwensCorninghaveintroducedinsulationpanelswithslottedgroovestoaccept woodfurringstrips. ADVANTAGES:Interiorappliedinsulation(Fig.2)iseasiertoinstallthanexteriorapplications;canbefairly inexpensivetoinstallinbattform. DISADVANTAGES:Interiorsurfacesofbasementwallsshouldbedry,asapplicationofinsulationcaninhibit MOISTER RETARDER MOISTER RETARDER FIGURE2. CONCRETE MASONRY BASEMENT WALL WITH INTERIOR INSULATION AND WOODFLOORONSLEEPERS detectionofinsectsandmoldwithinfurredwallcavity;mostrigidfoaminsulationrequiresa15-minute re-resistantthermalbarrier(usuallydrywall)toslowthespreadofretotheinsulation. Extrudedpolystyrene(XPS)boardhasbeenthematerialofchoicefortheexteriorinsulationof foundationwallsduetoitssuperiorcompressivestrength,impermeability,anddurabilitycomparedto expanded polystyrene (EPS), mineral wool, and polyisocyanurate products. XPS is made by Owens- Corning,TennecoBuildingProductsandDowChemicalwithanominaldensityof2pounds/cu.ft.EPS,how- ever,isalsopromotedinsomeareas,duetoitslowercost.Onemanufacturer,AFMCorp.,hasaproduct called Perform Guard that is treated with borate to discourage termite and carpenter ant infestation. SomeEPSmanufacturerssuggestusing1.5-or2-pound-densityboardonexteriorapplicationsinlieuof1 poundcommonlyusedforinteriorandroofinsulation,sinceathigherdensitiesEPSismoredurableand easilyhandled.Mineral-berorber-glassboards,suchasthoseusedinKochIndustriesTUFF-N-DRYsys tem,haveperformedsatisfactorily.EPSandpolyisocyanuratescanbeusedforinteriorapplications,along with insulating batts. Polyisocyanurate boards easily absorb water and are damaged with freeze/thaw cycling,sotheiruseshouldbeavoidedwherewaterisaproblem. 26

29 Relativelynewdevelopmentsincludeverticallygroovedextrudedpolystyreneboardstoenhance drainageagainstfoundationwalls.Forexample,OwensCorningsINSUL-DRAIN hasanetworkofdrainage channelscutintoonesideoftheboardwhichallowsgroundwatertodrainawayfromthefoundationwall. Tongue-and-grooveedgespermiteasierboardalignmentandhelpsealjointsbetweentheboards.Dows StyrofoamThermadry isalsomadewithdrainagechannels(seeChapter4:Drainage). FIGURE3. INSULATIONINSPECTIONSTRIP Asmentionedearlier,foamboardinsulationprovidesapotentialpathwayforinsect(particularly termite)inltration,intothehouse.Onewaytodetectthis,accordingtoatechnicalbulletinbyLiteForm International,istoprovideavisionstripbyremovingacontinuousstripofinsulation(exposingtheconcrete) aroundtheentireperimeterof thefoundation(Fig.3)priortocoveringornishingthewalls.Thestrips shouldbeapproximately12inchesabovegradelevelandapproximately8incheswide.Thebottomedge ofthecutshouldbetrimmedsothatitslopesawayfromthewallat45degreestoshedmoisture.Itshould benotedthatthisbreachintheinsulationseriouslyreducestheoverallR-valueofthesystem,andmay causecondensationtoformontheinteriorofthewall.Thebulletinalsorecommendsa20to22gauge continuousmetalashingstrip(termiteshield)beplacedatthetopofthefoundationwallbeforethewood sillplateisattached.Theashingshouldoverlaptheplateby1inchandturndowntoshedmoisture. Termiteshieldshavelongbeenrecommendedasawayofstoppingtermitetunnels.Recently,theirusehas FIGURE4. CONCRETEMASONRYCRAWLSPACEWALLWITHEXTERIORINSULATION 27

30 decreasedbecausetheyinterruptexteriornishesandcomplicatetheoverlapofsheathingandsidingatthe junctureofthefoundation.Whentheyareused,termiteshieldsareoftenpoorlyinstalled,damaged,orbent insuchawaythattheydonotprovideacontinuousbarrier. Somecodeagencieshaverecentrestrictionsagainsttheuseoffoamproductsbelowgrade.As this requirement continues to be researched, it is important to contact local ofcials for current use requirements.Inaddition,mostfoamproductmanufacturersareresearchingtheuseofinsectinhibiting chemicaladditivesintheirproducts.Codesrequiretheprotectionofinsulationboardonfoundationwalls abovegradelevel.DFIPultrudedComposites,Inc.,amongothers,makesarigid,1/16 inch-thickberglass panelthatcoverstheinsulation.Thepanelscomein12-or24-inchwidthsandhavea1inchlipthatgoes overthetopoftheinsulationboard. FURTHER READING Builders Foundation Handbook, John Carmody, et al., prepared for the U.S. Dept. of Energy by the UndergroundSpaceCenter,UniversityofMinnesota,1991. BuildingFoundationDesignHandbook,KenLabsetal.,preparedfortheU.S.Dept.OfEnergybythe UndergroundSpaceCenter,UniversityofMinnesota,1988. ConcreteMasonryHandbook,PortlandCementAssociation,1991. FineHomebuildingonFoundationsandMasonry,TauntonPress,1990. PreventingTermiteDamage, Lite-FormInternationalTechnicalBulletin,August1996. ShouldYouInsulatetheBasement?JournalofLightConstruction,June1992. PRODUCT INFORMATION PerformGuard,AFMCorp.,24000HighwaySeven,P.O.Box246,Excelsior,MN55331;8002550176. TUFF-N-DRI,KochMaterialsCo.,P.O.Box2155,Heath,OH430561132;8003792768. INSUL-DRAIN,OwensCorning,FiberglassTower,Toledo,OH43659;800GETPINK. StyrofoamTHERMADRY andStyrofoamWallmate,DowChemicalCo.,2040WillardH.DowCenter, Midland,MI,48674;8004414369. DFIPultrudedComposites,Inc.,1600DolwickDrive,Erlanger,KY41018;6062827300. 6.2 INSULATINGCRAWLSPACES ESSENTIAL KNOWLEDGE Crawlspacesareinsulatedtoprotectplumbingandductingthatmayrunthroughthespace,andtomitigate theeffectoftemperatureswingsonthelivingspacesabove.Crawlspacesareeitherventedorunvented, andinsulationstrategiesvaryineachcase. TECHNIQUES, MATERIALS, TOOLS Therearetwobasicapproachestoinsulatingcrawlspaces: 1.INSULATEVENTEDCRAWLSPACES. Thisapproachplacesbattinsulationbetweenthejoists,intheundersideoftherstoor,toprotectthe livingspace. ADVANTAGES:Oftentheleastcostlymethodofcrawlspaceinsulation,accomplishedwithmineralwoolor 28 berglassbatts;eliminatesneedtoinsulatecrawlspacewalls(requiredinunventedspaces);protectspipes

31 andductsthatrunintheplenumspacebetweenoorjoists. DISADVANTAGES:Maybedifculttoinstallifthereislimitedaccesstocrawlspace.Maybedifculttoseal theundersideoftheooradequatelywithavaporbarrierduetomultiplepenetrations.Requiresthatducts andpipesbelowtheoorbeinsulated. 2.INSULATEUNVENTEDCRAWLSPACES. Preferredbymanyresearchers,thisstrategyoftreatingthecrawlspaceasashallowbasementpermitsthe crawlspacetoactasaninsulatedandconditionedplenumspacethroughwhichpipesandductscanbe runwithoutfreezing.Italsoreducesoreliminateodors,insects,pests,dirt,anddebris.Crawlspacewalls canbeinsulatedfrominsideoroutsideinfashionssimilartothatforbasementwalls(Fig.1,2and4above, andFig.5and6below). ADVANTAGES:Exteriorrigidinsulationoncrawlspacewallscanberelativelyeasytoapplytothefoundation surface,andmaybetheonlyinsulationalternativewherecrawlspacesareinaccessible;reducesmoisture condensationproblems;allowsinspectionofcrawlspaceinteriorwalls(ifaccessible),sills,andrimjoists forinsectinfestation.Interiorinsulationintheformofboardsorbattscanbeappliedwithoutexcavation; canbeadheredwithmastictofoundationwall,orattachedtothetopofthewallanddrapeddown. DISADVANTAGES:Insulatingunventedcrawlspacescanbemorecostlythaninsulatingacomparablevented crawlspace; can be difcult to install interior insulation in crawlspaces with limited access; harder to inspectinsulation-coveredwallsforinsectinfestation. InsulationmaterialsandtechniquesarediscussedinTECHNIQUES,MATERIAL,TOOLS inSection6.1. MOISTURE RETARDER VAPOR RETARDER DAMP/WATERPROOFING RIGIDINSULATION PROTECTIONBOARD MOISTURERETARDER DAMP/WATERPROOFING FILTERFABRIC (WhereNecessary) DRAINPIPE FIGURE5,6. CONCRETECRAWLSPACEWALL SLAB-ON-GRADEWITH WITHINTERIORINSULATION CONCRETESTEMBEAM FURTHER READING Builders Foundation Handbook, John Carmody, et al., prepared for the U.S. Dept. of Energy by the UndergroundSpaceCenter,UniversityofMinnesota,1991. BuildingFoundationDesignHandbook,KenLabsetal.,preparedfortheU.S.Dept.OfEnergybythe UndergroundSpaceCenter,UniversityofMinnesota,1988. PRODUCT INFORMATION RefertoSection6.1. 29

32 6.3 INSULATINGSLABS ESSENTIAL KNOWLEDGE Therearetwobasictypesofslab-on-gradefoundations:thosewithconventionalfootingsandconcreteor masonrystemwalls(Fig.7)andthosewithshallowperimetergradebeams(Fig.8,9).Inrehabwork, insulationcanbeaddedonlytotheexteriorwithoutdisturbingtheslaboor. MOISTURE RETARDER VAPOR RETARDER DAMP/WATERPROOFING RIGIDINSULATION PROTECTIONBOARD FIGURE7. SLAB-ON-GRADEWITHMASONRYSTEMWALL VAPOR RETARDER MOISTURE RETARDER BATTINSULATION VAPOR RETARDER SILLSEALER DAMP/WATERPROOFING PROTECTIONBOARD RIGIDINSULATION MOISTURE RETARDER PROTECTIONBOARD FIGURE8,9. SLAB-ON-GRADEWITH SLAB-ON-GRADEWITHPERIMETER FROST-PROTECTEDSHALLOW TURNDOWN FOUNDATIONSYSTEM 30

33 TECHNIQUES, MATERIALS, TOOLS Therearethreebasicapproachestoinsulatingslabs: 1.EXTERIORINSULATIONFORSLABSWITHSTEMWALLS. Thestemwalldepthwilltypicallyvarywiththefrostline.Fulldepthinsulationisrecommendedinallareas ofthecountry.AnalternateinsulationstrategyistoinsulateinaccordancewiththeNAHBFrostProtected ShallowFoundation recommendations. 2.EXTERIORINSULATIONFORSLABSWITHGRADEBEAMS. ThistypeofslabistypicallyusedintheWest,Southwest,andSouth.Fulldepthinsulationisrecommended inareaswithmoderateorhighfuelcostsandHeatingDegreeDaysinexcessof2,000. 3.INSULATINGBASEMENTSLABSFROMINSIDE. Whilenotcosteffectiveintermsofenergysavingsversusrstcost,basementslabinsulationmakesnished oorsmorecomfortable.Thetraditionalmethod(Fig.2)istosealtheexistingoorwithavaporbarrier; fastenpressure-treatedwoodnailersorsleeperstotheoor;coverwithanothervaporbarrier(topreventmoist airfromcondensingintheoorcavity);installsheathing(plywoodorOSB);andnishwithwoodooringor resilienttile.Analternatemethodistooatthenewooroverlooselyappliedinsulationandsuboor. InsulationmaterialsandtechniquesarediscussedinMATERIAL,TECHNIQUES,TOOLS inSection6.1. FURTHER READING ConcreteFloorsonGround,EB075,PortlandCementAssociation,1997. SlabsonGrade, AmericanConcreteInstitute,1994. FrostProtectedShallowFoundations,NAHBBuildersPress,1994. DesignGuideforFrost-ProtectedShallowFoundationsSecondEditionNAHBResearchCenter,Inc.1996. PRODUCT INFORMATION RefertoSection6.1 31

34 7 V E N T I L AT I O N 7.1 VENTILATINGBASEMENTSPACES ESSENTIAL KNOWLEDGE Basementaircansufferfromsoilgases,mold,andmildew.Soilgasescanpenetratethebasementthrough cracksinfoundationwallsandslabsandthroughunsealedpenetrations.Moldandmildewgrowthisencour agedbycoolsurfacetemperatures,highrelativehumidity,andbythepresenceofmoistureinwallsand oors.Basementsareoftenusedtostoresolventsandfueltanks,whichoutgasvolatileorganiccompounds (VOCs).Thequalityofthebasementairalsoaffectsthequalityofairintheentirehouse.Ifthehouseuses aforcedairsystemforheatingorcooling,basementairisinducedintothereturnductsandatthefanhous ingandredistributedtootherspacesinthehouse.Ifthehouseisheatedwithahydronicsystemorwith electricbaseboards,thebasementaircanstillmigratetootherareas.Thistypeofairmovementcanbe reducedthroughsealingandcaulking,butisunlikelytobeeliminated. Ifthebasementisusedasalivingspace,itespeciallyneedstobeproperlyventilated.Without properventilation,indoorpollutantscanreachhighconcentrations.Evenifthebasementismostlyused forstorageormechanicalequipment,ventilationisimportantbecausecompleteseparationofbasement airfromhouseairisnotfeasible.Basementventilationisusuallyprovideddirectlythroughoperablewin dows,vents,orfans,orindirectlythroughairinltration.Airinltrationisnotagoodmethodofventilation becausetherateofinltrationvarieswithwindandtemperatureandcannotbereliedupontoprovide sufcientoutsideairatalltimes.Thebestsolutionistohaveanairtightbasementthatiswell-ventilated. For basements with boilers or furnaces, good ventilation also helps reduce the potential for depressurization.Whenabasementfurnaceorboilerpullsairfromtherestofthehouseforcombustion, andexhaustsitouttheue,alowpressurezoneiscreatedinthebasement,whichcanpullsoilgasesinto thespace.Iftheequipmentisplacedinanareaopentotherestofthebasement,depressurizationwill usuallybenegligible;iftheequipmentisenclosedinanairtightroomdepressurizationismoresignicant. Thebasementcanalsohavemorethanonecombustionappliance(afurnaceplusahotwaterheater). Theeffectoftheseappliancesringatthesametimeisadditive.Forairsystems,returnductsusuallypull airfromthebasement,causingdepressurization.Ductsshouldbesealedandtaped,butsomeleakagewill remain.Aseparatesupplyofoutsideairtothecombustionareaisbenecial.Thebasementcanalsobe pressurizedbytheairsystemtokeepsoilgasesout. Sinceventilationhasmanypositiveeffects,itisimportantthatitbeprovidedeffectively.Inmany residences,supplyofoutsideairtothecombustionequipmentisachievedbywindowsleftopeninthe basementspacethatcontainsthefurnaceorboiler,orbyaventwithinsectscreeninginstalledinthefoun dationwall.Thesemethodswillinducecoldairintothebasementduringwinterandmoistairduringsum mer,increasingtheenergycost.Additionally,thewindowthatprovidescombustionaircouldbeclosed accidentally.Forthisreason,windowsarenotrecommendedasameanstoprovidecombustionair. Combustionaircanbeductedincloseproximitytotheboilerorfurnace.Thismethodisnotthat differentfromcreatingascreenedopeninginthewall.Thebestsolutionistopurchaseequipmentthatis certiedasdirect-ventilation(sealed-combustion),andthatdrawstheoutsideairdirectlyintothecom bustionchamber.Thismethodraisestheenergyefciencyoftheheatingsystemandincreasesthesafety ofoperation.Ifsealedcombustionisnotfeasible,itispreferabletoprovideafanthatbringsinairtothe combustionequipmentonlywhenthisequipmentoperates. 32

35 TECHNIQUES, MATERIALS, TOOLS Thereareanumberofapproachestoprovidingadequateventilationtobasementsandsufcientcom bustionairforafurnaceorboiler,withoutcreatinglowpressurezonesthatdrawsoilgases: 1.PROVIDEDIRECT-VENTILATION(SEALED-COMBUSTION)BOILERSORFURNACES. Thistypeofmechanicalequipmentprovidesoutsideairforcombustionthroughaductthatleadsdirectly fromawallventtothecombustionchamberoftheboilerorfurnace. ADVANTAGES:Warmairfromthehouseisnotusedforcombustionandexhaustedthroughthechimney; theriskofincompletecombustionandofuegasbackowintothehouseiseliminated. DISADVANTAGES:Requiresextracosttopurchaseasealed-combustionboilerorfurnace. 2. PROVIDE A FAN WITH A MOTORIZED DAMPER TO INDUCE OUTSIDE AIR INTOTHEBOILERORFURNACEROOMONLYWHENTHEEQUIPMENTFIRES. Thismethodprovidescombustionair,andissimilartothesealedcombustiontechnique,exceptthatthe combustionairisnotducteddirectlytotheequipmentandhastocrosstheboilerorfurnaceroom.When theequipmentdoesnotrethedamperclosesoverthefananddoesnotallowcoldairtoseepin. ADVANTAGES:Warmairfromthehouseisnotusedforcombustionandexhaustedthroughthechimney; theriskofincompletecombustionandofuegasbackowintothehouseiseliminated. DISADVANTAGES:Extracostandsomewhathighercomplexitythanforawindoworvent. 3.PROVIDEASCREENED,OPENVENTTOALLOWOUTSIDEAIRINTOTHEBASE MENTNEARTHEFURNACEORBOILER. Theconstantlyopenedventallowsoutsideairintotheboiler/furnaceareaofthebasementatalltimes(oper ablewindowsarenotarecommendedalternative,becausetheymightbeclosed).Tomitigatetheintrusion ofcoldormoistairthroughoutthebasement,thefurnaceorboilershouldbeenclosedinitsownroom. ADVANTAGE:Alow-tech,low-costsolution. DISADVANTAGES:Theequipmentmustbelocatednexttoanexteriorwallwithventopeningabovegrade; iflocatedclosetoexteriorgradelevel,theventwillrequiremaintenancetokeepitfreefromdebrisor snow.Theairintheboiler/furnaceroomcangetcold,increasingtheheatlossfromtheequipmentand thereforeincreasingthefueluse.Also,itispossible(evenifnotlikely)thatunderstrongwindconditions asupplyventplacedontheleewardsidecouldexhaust air,ratherthanadmitit. 4.SEPARATETHEBASEMENTAIRFROMTHEAIRINTHERESTOFTHEHOUSE. Separationofbasementairfromhouseairisdesirablewhenthebasementisnotusedforlivingspace. Thepurposeistominimizemixingbasementair,thatcouldbepollutedbydust,mold,orVOCs,withcon ditionedairforthehouse.Thebasementspaceisseparatedfromtherestofthehousewithdoorsand continuousoor.Basementventilationisprovidedbyadequatelysizedwindowsormechanicalintakeand exhaustfans.Thebasementisheatedwithahydronicsystem,electricbaseboardheat,orwithaseparate airheatingsystemthatkeepstheairfromthebasementfrommixingwiththerestofthehouse.Containers thatcanoutgasVOCsarestoredinanairtight,enclosedroom.Thisroomshouldhavecontinuousexhaust totheoutdoors.Fanhousingsandductsinthebasementthatservethehousemustbesealedandtaped toavoiddrawingbasementairintotherestofthehouse. ADVANTAGES:Thebasementiswellventilated,andtheairintherestofthehouseiscleaner. DISADVANTAGES:Ifaheatedairsystemisusedforthehouse,therewillbesignicantaddedcostfora separate,decoupledairsystemforthebasement(orforaseparatehydronicorelectricheatsystem).Extra costsareincurredtocarefullysealfanhousingsandductsinthebasementthatservethelivingarea. 5.TREATTHEBASEMENTASCONTIGUOUS,CONDITIONEDSPACEOPENTO THERESTOFTHEHOUSE. Thismethodisrecommendedwhenthebasementismaintainedtothesamestandardsofcleanlinessasa livingspace.Separateventilationforthebasementcanbeprovidedwithwindows,ormechanicalintake 33

36 FIGURE1. ECHOSYSTEMPERFORMANCECHARACTERISTICS andexhaustsystems.Thebasementcanalsobeventilatedusingoutsideairbroughtinbytheairsystem thatservesthehouse.Ifanairsystemisusedfortheentirehouse,ductslocatedinthebasementmustbe well-sealedtoavoidpressureimbalancesthatcouldleadtothesuctionofsoilgases.Anadditionalstepin avoidingsoilgasseepageistopressurizethebasement.Thisconditioncanbeachievedbysupplyingout- sideairattheupperoorsandbyexhaustingatthebasementlevel. ADVANTAGES:Canprovideproperventilationinthebasementatalltimes. DISADVANTAGES:Possiblediscomfortattimesaswarmairrisesandtheupperspacesoverheat,whilethe basementremainscooler.Adjustabledampersintheductsleadingtoeachoor,ormechanicaldestrati cationducting,willremedythisproblemataddedcost.Also,tightbasementwallswillreducetheair inltrationrateinthebasement,andwillreducetheairowfrombasementintootherspaces. 6.PROVIDEAVENTILATEDROOMWITHINAROOM. Whenwallsarecontinuouslymoistfromwaterpenetration,orwhenradoncannotbesatisfactorilycontrolled withEPA-recommendedtechniques(seeSection7.3),roomsorareaswithinthebasementspacecanbe builtthathavecontinuousairexhaustundertheoorandinthewallcavitybetweentheroomswallsand the basement walls. This innovative technology, called the ECHO system (Fig. 1) is sold by Indoor Air Technologies,Inc.Ideally,thefurnace,boiler,ordomestichotwaterheaternearbyshouldhavesealedcom bustion,withaductedoutsideairsupply.Moreimportant,thereturnductsandfanhousingneedtobe wellsealedtoavoidairbeingdrawnfromthebasement,creatingnegativepressurethatcanreducethe effectivenessofthissystem. ADVANTAGES:Addressesseveralaspectsofbasementairquality.Effectivewhenexteriorsourceproblems cannotbeeliminated.Theinsulationinstalledontheinteriorwalls(notonthefoundationwalls)remains 34

37 dryevenifthebasementwallsleak. DISADVANTAGES:Requiresmonitoringofequipmentandconditionsinventilatedwallspaces.Canbecostly. FURTHER READING CleanAirGuide,CanadaMortgageandHousingCorp.,1993. ControlofMoistureProblemsAffectingBiologicalIndoorAirQuality,B.FlanniganandP.R.Morey, InternationalSocietyofIndoorAirQualityandClimate,1996. MoistureControlHandbook,JosephLstiburekwithJohnCarmody,U.S.Dept.OfEnergy,1991. MoistureControlinBuildings,HeinzR.Trechsel,ed.,ASTM,1994. IndoorAirQualityAndClimate:Investigation,EvaluationandRemediation,IndoorAirTechnologies, Ottawa,ON,CanadaKIVOW2 PRODUCT INFORMATION ECHOSystem,IndoorAirTechnologies,Inc.,P.O.Box22038,Sub32,Ottawa,Ontario,CanadaK1V0W2, 8005585892. 7.2 VENTILATINGCRAWLSPACES ESSENTIAL KNOWLEDGE Theventingofmanyexistingcrawlspacesisinadequateandmoistureandodorproblemsarefrequently apparent.Moistureencouragesmold,mildew,andwoodrot,anddegradesinsulationR-value.Thereis currentlymuchdebateabouttheratioofventilationareatooorarea.Buildingcodestypicallyrequire thatcrawlspacesbeprovidedwithventilationopeningsinthesurroundingwallswithanetfreeareaof1 squarefoot foreach150squarefeetofcrawlspacearea,orreducedto1/1,500 ofthecrawlspaceareawhen anapprovedmoistureretarderisusedoverthegroundsurface.Naturalventilationisusefulduringdrywin termonths,butcanactuallyincreasethemoistureinthecrawlspaceduringhumidwinterspellsandduring thecoolingseason,inareaswithhumidsummers.Crawlspacesthatarenotventilatedwithfoundation ventsmustbeequippedwithamechanicalventilationsystemconformingtoanapprovedmechanicalcode. TECHNIQUES, MATERIALS, TOOLS Thereareanumberofapproachestoventilatingcrawlspacesandmitigatingmoistureproblems: 1.NATURALLYVENTILATETHROUGHREQUIRED-SIZEDOPENINGSINTHE FOUNDATIONWALL. Ventilationcanbeachievedthroughtheexistingfoundationwallbyremovingportionsoftheblockorcon cretewallandinstallingventilationgrilles.Theoorabovethecrawlspacemustbeinsulated,astemper aturesinsidethecrawlspacewillbeseasonal(seeSection6.2:InsulatingCrawlspaces).Specialcaremust betakentoinsulatewaterandwastepipinglocatedbelowtheoorinsulation.Dirtoorsareamajorsource ofmoistureincrawlspacesandshouldbecoveredwithapolyethylenemoisture retarder.Aconcreteslab, orotherprotectivesurface,canbeplacedoverthepolyethylenetoprotectthesheetagainstdamage. ADVANTAGES: Compared to mechanical ventilation, this approach is relatively inexpensive in terms of operatingcosts;requireslittlemaintenance. 35

38 DISADVANTAGES:Requiresinsulationofoorabovecrawlspace,whichmaybedifcultorimpossibleto achieve.Insulationmustbetightlypackedbetweenoorjoists;anyairspacesbetweentheinsulationand thejoistspromoteairconvection,whichshortcircuitstheinsulation.Removingportionsoftheexisting foundationwallsmaynotbepossibleorpracticable,suchaswithrubblestonewallsorconcretewalls withrebar.Naturalventilationmaynotalwaysprovideenoughairowtoremovemoisture,andmayinduce moistureinsummerandduringhumidwinterperiods.Removablecoversforthegrillescanaddressthis problem,butaddamaintenancecost. 2.MECHANICALLYVENTILATETHEUNCONDITIONEDCRAWLSPACE. Thisoptionissimilartotheonediscussedin1above(naturalventilation),exceptthattheventilationis mechanicallyprovided.Thereareventilationsystemsonthemarket,suchastheCellarSaverbyTamarack Technologies,thatcanbeadjustedtoactivateatacertainhumiditylevel.Theyalsohaveinsulateddampers thatclosewhenthefansarenotinuse. ADVANTAGES:Ensuresaminimumventilationrateevenwhenthereisnobreeze.Dampers,manualorauto matic,closethecrawlspacetohumidoutsideairwhenthefansareoff. DISADVANTAGES:Sameconstructiondrawbacksasoption1;additionalcostofoperatingandmaintaining thefans. 3.MECHANICALLYVENTILATETHESEMICONDITIONEDCRAWLSPACE. Thisstrategyessentiallytreatsthecrawlspaceasabasementspace,ventilatingitsimilarlythroughmechan icalmeans.Thecrawlspaceismechanicallyheatedinadditiontobeingventilated.Thefoundationwallsare insulated(seesection6.2:InsulatingCrawlspaces). ADVANTAGES:Ensuresthatventilationistimelyandsufcient.Whenthecrawlspaceisproperlyinsulated, thistechniquesavesmoneyinfuelcostsandextendsthelifeoftheoorstructure. DISADVANTAGES:Higherinitialcost.Requiresaccesstocrawlspaceforinstallationandtoobservecondition ofspaceandequipment. FURTHER READING InvestigationofCrawlSpaceVentilationandMoistureControlStrategiesforBritishColumbiaHomes, CanadaMortgageandHousingCorp.,1991. MoistureControlHandbook,JosephLstiburekwithJohnCarmody,U.S.Dept.OfEnergy,1991. MoistureControlinBuildings,HeinzR.Trechsel,ed.,ASTM,1994. RecommendedPracticesforControllingMoistureinCrawlSpaces,TechnicalDataBulletin,Vol.10,No. 3,January1994ASHRAESymposium. PRODUCT INFORMATION CellarSaver,TamarackTechnologies,Inc.,11PattersonsBrookRoad,P.O.Box490, WestWareham,MA02576;8002225932. 7.3 VENTILATIONFORSOILGASES ESSENTIAL KNOWLEDGE Inthepastfewyears,awarenessofthedangersofsoilgases,especiallyradon,hasgrown.Accordingtothe U.S.EnvironmentalProtectionAgency,14,000cancerdeathsintheU.S.arecausedbyradoneachyear.The 36

39 FIGURE2. PASSIVESUBSLABDEPRESSURIZATIONRADONCONTROLSYSTEM EPAestimatesthatoneoutofevery15houseshaselevatedradonlevels,withconcentrationsheavierin someregionsthaninothers.Acolorless,odorless,radioactivegas,radonismostoftenfoundinbase ments, entering through crawlspaces, dirt oors, cracked foundation oors and walls, and openings arounddrainpipesandsumppumps. TECHNIQUES, MATERIALS, TOOLS The EPA has released details of techniques for radon abatement in basements and crawlspaces. Considerationshouldalsobegiventothemechanicalventilationsystemseffectonradoncontrol: 1.PROVIDESUB-SLABVENTILATIONOFSOILGASESINBASEMENTSPACES. Ventpipespenetratingtheslabcanrunverticallythroughthehouse,andbeventedouttherooforaside wall.Theventpipehasacontinuouslyoperatingexhaustfanthatmaintainsnegativepressure.Allcracks andpenetrationsthroughtheslab,andjuncturesbetweentheslabandthewalls,shouldbesealedwith caulkingorgrout.Newslabsshouldbepouredona4-inchlayerofgravelorsand,overlaidwithagas- retardermembrane(Fig.2,3). ADVANTAGES:Anapprovedtechnique,endorsedbyEPA,thateffectivelyexhaustsgasesbelowtheslab. DISADVANTAGES:Canbecostly,dependingonsizeofbasementandcongurationofhouse.Lesseffective whenthebasementwallsaremadeofhollowcoreconcretemasonryunits(CMU),sinceradoncouldnd pointsofentryintosuchwalls.Incoldclimates,thereisthepossibilityoffrostheavingduetothecoldair introducedundertheslab. 37

40 FIGURE3. ADDITIONALCOMPONENTSREQUIREDFORACTIVATIONOF DEPRESSURIZATIONRADONCONTROLSYSTEM 2.PROVIDEFOUNDATIONWALLDEPRESSURIZATION. Thefoundationwallisdepressurizedthroughweepingtiles(draintiles).Acontinuouslyoperatingexhaustfan maintainsnegativepressure.Allcracksandpenetrationsatthewallshouldbesealedwithcaulkingorgrout. ADVANTAGES:Relativelyeasytoimplement. DISADVANTAGES:Theareaprotectedbythistechniqueislimited;fanmustoperateatalltimes;ineffective ifweepingtileisconnectedtothesewersystemortoroofleaders. 3.PROVIDEBASEMENTHEATINGANDVENTILATION,SEPARATEBASEMENTAIR FROMTHATOFTHERESTOFTHEHOUSE,ANDPRESSURIZETHESPACETOKEEP OUTSOILGASES. Thisapproach,similartothatdiscussedinsection7.1,isusefultosupplementtheEPA-recommended radonmitigationtechniquesdescribedabove.Pressurizationisachievedviaadedicatedairsystemforthe basement,withanoutdoorairintake.Thistechniqueensuresthatthebasementisalwaysatapositive pressurewithrespecttoairspacesinthebasementwallsandinthecavitiesbelowtheslab.Thisapproach ismostusefulinbasementswithCMUwallswithhollowcores,throughwhichradoncanenter.Ifafurnace, boiler,ordomestichotwaterheaterislocatedinthebasement,combustionairmustbeductedtoasealed appliance,oroutsideairmustbesuppliedusingafanwithdamper(thefanoperatesonlywhentheappliance res).Openwindowsorscreenedventsarenotrecommendedbecausetheycancompromisepositivepres sure.Ifthehousehasanairsystem,fanhousingsandductsmustbesealedandlappedtoavoidentraining basementair. ADVANTAGES:Ensuresgoodventilation;increasedeffectivenessinkeepingradonout. DISADVANTAGES:Signicantcostrequiredtoachieveatightbasement/houseseparation;signicantcostin supplyingadedicatedairsystem,suchasafurnacewithoutsideairsupply;additionalcostforaductedout- 38

41 FIGURE4. PASSIVERADONCONTROLSYSTEMINCRAWLSPACEFOR NEWCONSTRUCTION sideairsystemforcombustion(althoughsuchsystemisagoodideaevenifthebasementhasnoradon problems;seeSection7.1). 4.PROVIDEVENTILATIONOFSOILGASESFROMCRAWLSPACES. Whereacrawlspaceslabexists,thetechniqueissimilartothatdescribedforbasementspaces(above). Fordirt-oorcrawlspaces(Fig.4)perforatedpipeshouldbelaidoverthesoil,paralleltothehouseslong dimension,andshouldextendnocloserthan6feettothefoundationwall.AT-ttingjoinstheperforated pipetoanexhauststackthatextendsthroughtheroof.Thepipeandcrawlspaceoorarethencovered withagasretardermembrane,andsealedagainstthefoundationwallandallverticalpenetrations. ADVANTAGES:AnapprovedtechniquesanctionedbytheEPAthateffectivelyexhaustssoilgases. DISADVANTAGES:Canbecostly,dependingonsizeofcrawlspaceandcongurationofhouse. 5.PROVIDEAVENTILATEDROOMWITHINAROOM. RefertoSection7.1,option6.TheECHOsystemdescribedthereisalsoeffectiveinreducingradonpen etrationintobasementandintootheroccupiedspaces. FURTHER READING GuidetoRadonControl,CanadaMortgageandHousingCorp.,1990. ModelStandardsandTechniquesforControlofRadoninNewResidentialBuildings,March1994. Radon-ResistantConstructionTechniquesforNewResidentialConstruction:TechnicalGuidance,U.S. EnvironmentalProtectionAgency,1991. SelectedDetail:RadonAbatement,MichaelJ.Crosbie,ProgressiveArchitecture,Nov.1994,p.125. 39

42 8 SHORING, UNDERPINNING,& R E PA I R ESSENTIALKNOWLEDGE Whenafoundationsettlesorisdisplacedlaterally,cracksappear,watermayintrude,andthebuildingsbasic structureiscompromised.Foundationwallsmaycrack,settle,moveupwardsfromfreeze/thawcyclingor expansivesoils,ormovesideways.Theprimarycausesofsuchfoundationfailuresare:problematicsites; poorsoilconditions;seismicactivity;watermigrationthroughsoilsorooding;poorfoundationdesign, engineering,orconstructionmaterials.Problematicsiteconditionsincludesteepslopesbeyondthesoils naturalangleofrepose;lackofterracingunderll;siteswithhighwatertables,springs,orunderground streams;andsitesadjacenttobodiesofwaterorwithinoodplains.Poorsoilconditionsincludehighly expansivesoils;organic(peatordiscardedplantmaterial)orsiltysoils;andpoorlycompactedllthatwas notlayeredwhenitwasplaced.Seismicactivitycandamageinadequatelyreinforcedbrick,concrete,concrete block, or stone foundations. Water-related damage includes the migration of nes under foundations, decreasedsoilcohesiveness(whichcausessettlement),andhydrostaticpressureagainstfoundationwalland oors(whichcanleadtocracksanddisplacement).Poordesignandengineeringmayresultinimproper materials,under-reinforcement,orlackofattentiontomanyoftheconditionsmentionedabove. Foundationsettlementusuallyhappensovertime,andisnotadramaticevent;thereisusually timetoprepareaproperx.Thecauseofthesettlementshouldbecarefullyanddeliberativelyresearched, asremedialworkisexpensiveandcareshouldbetakentounderstandthenatureoftheproblem.Astruc turalengineerorasoils(geotechnical)engineerwhospecializesinsuchworkshouldbeconsulted. TECHNIQUES,MATERIALS,TOOLS Thereareanumberofapproachestostabilizingandre-positioningfoundations,whichareapplicabletoall types,includingstemwalls,pierswithgradebeams,andslabsongrade.Someofthesesystemsarecom monlyusedtorepaircommercialorindustrialbuilding,buttheycanalsobeusedforresidentialmulti- familyandsingle-familyhousingrehab.Repairsshouldbeundertakenbyexperiencedcontractorsunderthe directionofaprofessionalengineer. 1.STABILIZEANDUNDERPINSETTLEDFOUNDATIONWITHREINFORCED CONCRETEPIERS. Thisprocessinvolvesauguringapierexcavationnexttothesettledportion,insomeinstances(suchaswith granularsoils)insertingroundcardboardforms,placingreinforcingsteel,andpouringaconcretepier includinganelboworcapundertheexistingfooting.Concretepierscanbearonrockorcanbedesigned asfrictionpiers.Oncetheconcreteiscured,ahydraulicjackcanbesetbetweenthenewlyformedelbow orcapandtheundersideofthefooting(Fig.1).Thejackdistributestheloadtothenewpierandraises thesettledportion.Shimsaretheninsertedtoholdtheraisedfoundationinplacesothatthejackcanbe removedandthejointpackedwithano-slumpmixtureofsandandcement(drypack).Thenumberof piersisdeterminedbythetypeoffoundationandthesizeofthesettledportion.Iftheloadsaresmalland 40

43 FIGURE1,2. REINFORCEDCONCRETEPIER MINIPIER thesoilscapacityisgood,thejackcanbeeliminatedandtheloadstransferredthroughtheshimsdirectly. ADVANTAGES:Aconservativeapproach,withaproventrackrecord. DISADVANTAGES:Limitedindepthinsandysoilsthatwillcollapsetheaugerhole.Maynotworkasfriction piersinsoilwithpoorbearingcapacity.Requiresconcretetocuresufcientlybeforeloadisapplied. Difcult toraisethefoundationmorethanafewinches.Moredisruptivetolandscapedareasadjacenttothebuild ingthanminiorhelicalpiers. 2.STABILIZEORRAISESETTLEDFOUNDATIONWITHSTEELMINI-PIERS. Usuallyhydraulicallydriven,mini-piersrangefrom2to8inchesindiameter.Thesmallersizes,2to4inches, aretypicallyusedinresidentialprojects.Thepiersaresetadjacenttotheinteriororexteriorfaceofthefoot ingatintervalsof6to8feet,dependingontheconditionandreinforcementofthefooting(Fig.2).Theyare thenhydraulicallyorpneumaticallyinstalledthroughadriveframemountedonthefoundationwalltorock oranadequatebearingstrata.Thebuildingsdeadweight,plustheweightofthesoiladheringtothefooting andfoundationwall,providetheresistance/reactionduringinstallationofthemini-piers.Thepiersareusu allydriventodepthsof15to25feet,andcangoasdeepas150feet,butareincreasinglyuneconomicaland difculttodriveover60feet.AnumberofcompaniesincludingAtlasSystems,Inc.andPerma-Jackhold patentsonmini-pierproductinstallationsystems.Anothervariant,calledtheMini-Pile system,developedby HeywoodBaker,Inc.,employsanover-sizedpointthatconcentratesresistanceattheendofthepipepile.The pileishollow,andifbedrockisnotencounteredagroutbulbcanbepressureinjectedattheendofthepipe tosupplythenecessarybearing.Therearetwoattachmentsystemsoneusedinexpansivesoilattachesto the foundationbymeansofasteelbracket;theotheremploysa12-inchthickreinforcedconcretepilecap/jack ingpadthatisusedtoseatahydraulicjackthatisinturnusedtoraisethefooting.Thespacebetweenthesur faceofthejackingpadandthefootingundersideisthenlledwithconcretetocompletethepilecap. ADVANTAGES:Time-proven,economical,andstable,wherebearinglayeriswithin50to60feetofgrade. Noheavyequipmentrequired;canbeinstalledinlimitedaccessareasandbeusedtoraiseslabs. DISADVANTAGES:Cancrackfoundationandslabifusedincorrectly.Economicaluserequiresbearinglayerto berelativelyneartograde,and2-to3-footsquareaccesspits,whichcandisturbthefoundationperimeter ifmultiplepitsshortdistancesapartareused. 3.STABILIZEORRAISESETTLEDFOUNDATIONWITHHELICALPIERS. Apatentedsystemthatscrewsasteelshaftwithahelicalplateintostablesoil.Thesteelshaftattachestothe footingandfoundationwallbymeansofabracket.Therotationofthehelicalplatebyahydraulicjackwill eventuallycauseenoughresistancetostabilizethefoundationorraiseit,ifnecessary(Fig.3).Installersof thehelicalpiersystemaretrainedandlicensedbysuchcompaniesasA.B.ChanceCo.andAtlasSystems, 41

44 Inc.,whichprovidegeotechnicalsupport.Warrantiesareavailable. ADVANTAGES: Aproven,versatile,technicallysoundsystem.Economicalandnotasdisruptiveassomeother methods.Noheavyequipmentrequired.Canbeinstalledinlimitedaccessareas;canbeusedforshallow pierfoundations,asawallanchortopullbackandholdbasementwalls,andtoraiseslabs.Hydraulicjack torquecanbemeasured,therebydeterminingactualbearingcapacitiesofhelicalpiers. DISADVANTAGES:Willnotworkinsoilsoflimitedbearingcapacity.Maydisturbbuildingperimeter,including walksandplanting,ifon-centerspacingofpiersisclose.Requiresnotchingthefootingtoapplythebracket. FIGURE3. HELICALPIER 4. STABILIZEORRAISESETTLEDFOUNDATIONBYPRESSUREGROUTINGOR MUDGROUTING. Thistechniquepressureinjectsaslurryofcement,water,andsandintothesoiltostabilizethefoundation ortoraisethebasementslab.Thismethodisdifculttocontrol,andthelocationofthegroutanditseffect areimpossibletodetermine.Itismorecommonlyusedforslabstabilizationandlessforfoundationshoring, whereothertechniquesareconsideredmorereliableandcosteffective. ADVANTAGES:Aneconomicalsolution,ifitworks. DISADVANTAGES:Oftennoteffective;difculttocontrolandevaluate;maycrackslabs;groutmaytravel wellbeyondthedesiredtreatmentarea. 5.STABILIZEORRAISEFOUNDATIONWITHCOMPACTIONGROUTING. Compactiongroutinginvolvesthepressureinjectionofaverylowslumpgroutthroughaburiedpipetodis place and compact soils. Major uses include: densifying loose and poorly compacted soils; lling voids includinglargesinkholes;preventingliquicationofsoilsduetoseismicactivitybydensifyingthesoilbeyond theliquicationthreshold;re-levelingsettledstructures;usingcompactiongroutbulbsasstructuralelements formini-pilesorunderpinning.Thekeytothesystemssuccessisthatthepumpedgroutremainslocaltothe areaaroundtheburiedpipeanddoesnotmigrate,aslesscontrolledformsofpressuregroutingdo. ADVANTAGES:Relativelycontrollable;widevarietyofapplications.Remainsinamassandcandisplace poorsoils.Canbeusedtoraisefoundationsandslabs.Cost-effectiveprimarilyforlargeprojectssuchas townhousesandmulti-familybuildings. DISADVANTAGES:Too expensiveforsomesingle-familyhousefoundationrepairs.Requiresaccessbyheavy machinery.Notrecommendedinsaturatedclaysoilsorinsoilscontaininghighamountsoforganicmaterial. 42

45 6.STABILIZE,WATERPROOF,ORRAISEFOUNDATIONORSLABWITHVARIOUS HIGHLYSPECIALIZEDGROUTINGTECHNIQUES. Avarietyofotherspecializedgroutingtechniquesexisttostabilizefoundationsinlargerbuildings,suchas multi-familyhousing.Commonlyusedbyfoundationrepairspecialistsaroundthecountry,these techniques includejetgrouting:highpressureliquidgroutingtoformasoilcementcalledsoilcreteusedforsophisti catedunderpinningwork;chemicalgrouting:injectingsodiumsilicateintosandysoilstostabilizethemand makeakintosandstone;urethanegrouting:towaterproofunderslabsanddifcult-to-accessspaces;vibro compaction: uses probe-type vibration to densify granular soils; injection systems: for expansive soils, injectingpotassium,lime,andwatertolimitmovement. ADVANTAGES:Sophisticated,site-specictechniquesthatcansolvedifcultproblems. DISADVANTAGES:Expensiveandnotnormallyusedinresidentialrehab. 7.UNDERPINMASONRYORCONCRETESTEMWALLWITHENLARGEDFOOTING. Ifthesettlementofafoundationwallislocalized,itmaybepossibletounderpinthefoundationdirectlyby increasingthefootingsizeinordertodistributethewallloadsoveragreaterarea.Thisprocessinvolvesjack ingaportionofthehousetotaketheloadoffthefoundationwall,excavatingaportionofthefooting(in alternating3-to6-footsections,forexample),addingsteelreinforcement,andllingthefootingexcavation withconcrete).Aftertheconcretehascuredsufciently(usually7days)theintermediatesectionscanbe excavatedandtheprocessrepeated.Alternatively,ifthewallisseriouslydeteriorated,anewwallandfooting canbeerectedalongsidetheexistingwall. ADVANTAGES:Relativelyinexpensive,expedientlocalrepairifaffectedareaofthefoundationisrestricted toarelativelysmallperimeter. DISADVANTAGES: Workshouldbedesignedbyanengineersothatthenewfootingissizedandreinforcedfor theexistingsoilconditions.Adangerousprocedurethatshouldbeundertakenbyexperts.Maynotworkin siltyorexpansivesoilsasthenewfootingmassmaycontinuetosettle.Notcosteffectiveoverlongwalllengths. 8.BUTTRESSSTONEFOUNDATIONWALLS. Freeze/thawaction,expansivesoil,migratingwater,andhydrostaticpressurecanallraisehavocwithstone foundationwalls,particularlythoselaidwithoutmortar.Insomecaseswallsmayberepointedorstabilized fromeitherinsideoroutside.Inothercases,thepointingmaynotbecosteffectiveandmaynotbeeasily waterproofedduetoirregularsurfaces.Arepairthatcanbothstabilizeandwaterproofstonewallsisshown inFig.4.Inthiscase,anewconcretesurfacingispouredintothecavitybetweenplywoodformsandthe FIGURE4. BUTTRESSINGSTONEFOUNDATIONWALL 43

46 existingwallface,consolidatingthewallandprovidingasmoothsurfaceonwhichtoapplywaterproong. ADVANTAGES:Allowstheexistingwalltoremain;reinforcesandwaterproofsthewall. DISADVANTAGES:Requiresexcavationandformwork;canbeexpensive. 9.REPLACETHEFOUNDATION. Extensivesettlement;unsightly,cracked,ordisplacedfoundationwalls;rottingsillplates;ortheneedtogain additionalheightinabasementmaynecessitatethereplacementofallorpartofthefoundation.Whenonly onefoundationwallistobereplaced,platformframingoffersseveraloptions.Iftherstoorframingisper pendiculartothewall,itmaybepossibletoplaceasupportinggirderjustinsidetheexteriorwall,parallel toit(Fig.5).Instructureswherethejoistsrunparalleltotheexteriorwall,needlebeamscanbeplacedper pendicularandunderthewalltosupportitwhilethefoundationisreplaced(Fig.6).Iftheentirehouseis beingraised,asystemofcarryingbeams,cribbing,andjacksshouldbedesignedtosupportthecriticalload- carryingmembersofthehouse.Analternativetousingcribbingandjacksistoinstallhelicalpierstopro- videthefootingforacolumnsupporttotemporarilyunderpinportionsofthestructure.Professionalguid anceshouldbesought. ADVANTAGES:Providestheopportunitytobuildnew,dryliving/storagespacewhilexinganumberof basicproblems. DISADVANTAGES:Canbeexpensive.Requireschangestoallplumbingandelectricalserviceconnections; requiresskillsbeyondthoseofmosthouse-buildingcontractors. FIGURE5. JACKINGAWALLWITHPERPENDICULARJOISTS 44

47 FIGURE6. JACKINGAWALLWITHPARALLELJOISTS FURTHERREADING Renovation:ACompleteGuide,MichaelW.Litcheld,Prentice-Hall,1991. So Your House is Built on Expansive Soil, edited by Warren K. Wray, American Society of Civil EngineeringPress,1995. TheDaytheHouseFell,RichardC.Handy,Ph.D.,AmericanSocietyofCivilEngineeringPress,1995. PRODUCTINFORMATION A.B.ChanceCompany,210NorthAllenStreet,Centralia,MO65240;5736828414. AtlasSystems,Inc.,3114WeatherfordRoad,Independence,MO64055;8003259375;www.atlassys.com HeywoodBakerGeotechnicalEngineersandDrillingContractors,1875MayeldRoad,Odenton,MD21113; 4105518200. Perma-JackofKansas,201SouthHaverhill,ElDorado,KS67042;8007369255. 45

48 9 C R A C K R E PA I R , C O AT I N G S &FINISHES 9.1 CRACKSINWALLSANDSLABS ESSENTIAL KNOWLEDGE Basementwallandoorcrackscanbecausedbyavarietyoffactors,includingdryingshrinkage,thermal contraction,restraint(internalorexternal)toshortening,subgradesettlement,andappliedloads,including thoseduetoexpansivesoils,hydrostaticpressurefromhighwatertables,andinsomepartsofthecountry, seismicactivity.Factorsthatcancontributetocrackingproblemsincludeinadequatereinforcementincon crete,concreteblock,andstonewalls,incorrect/lackofconstructionandcontroljoints,andimproperly mixedorplacedmortarorconcrete.Stationaryhairlinecracks(those1/16 inchandlessinwidth)areusu allynonstructuralandareprimarilycosmeticconcernsunlesstheyareassociatedwithmoistureproblems. Cracks1/8 inchinwidthandgreatermayalsobenonstructural,butmayreectsignicantwallsettlementor displacement.Repairshouldnotbeundertakenuntiltheprincipalcauseofthecrackinghasbeendeter- mined(seeChapter8:Shoring,Underpinning,andRepair). TECHNIQUES, MATERIALS, TOOLS 1. REPAIR CRACKED AND OUTWARDLY DISPLACED FOUNDATION WALL BY EXTERIORJACKING. Ifasectionofafoundationwallhasbeenoutwardlydisplacedbeyondtheplaneoftheadjacentwalls,it maybepossible,ratherthanrebuildingthatsection,tomoveitbackintoplace.Thiscanbeaccomplished byexcavatinginfrontofandtothesideoftheaffectedsectionandjackingthedisplacedwallbymeansof hydraulicramjacks(Fig1).Caremustbetakentoprovideajackingpadofsufcientareasothatthejack doesntpunchthroughthewall.Itisalsoimportanttoshoreuptheexcavationagainstwhichthewallis jacked,andtoprovidedrainagefromtheexcavationintheeventofrain. ADVANTAGES:Lessexpensivethancompletelyreplacingportionsofthewall.Allowsvisualinspectionofwall conditionsandprovidesanopportunitytowaterproofthewallandinspectdrainage. DISADVANTAGES: Wallconditionmaynotpermitjacking.Thewallmaynotbealignedwhenjackingis complete.Crackswillrequirepatching,grouting,andwaterproong.Thistechniquewilldisturbgrounds andplantingsadjacenttheaffectedwallportion. 2. STABILIZE CRACKED AND INWARDLY BOWED FOUNDATION WALL BY USE OFEARTHANCHORANDWALLPLATE. Ifanuppersectionofthefoundationwallhasbeeninwardlydisplaced,usuallyatthemidpointofthewall, itmaybepossibletostabilizeorstraightenthewallwithanearthanchor(Fig.2).Typicallyinstalledin anexteriortrenchapproximately6feetoncenterhorizontallyandbelowtheaveragefrostdepth.TheGrip- 46

49 FIGURE1,2. JACKINGCRACKEDFOUNDATIONWALL EARTHANCHOR Tite wall anchor system utilizes an anchor rod that is pushed through the soil by means of a hammer drill/rotaryhammerfromareinforcedwallplatethrougha11/8 inchholeinthefoundationwalltoanearth anchorplatesetatadistanceof7to8feetfromthefaceoftheexteriorwall.Theanchorrodhasanutand washerthatistightenedwithatorquewrenchagainstthewallplate,usuallyduringdryseasons.Thewall canbebroughtbacktoamoreverticalpositioninaprocessthattakes,accordingtothemanufacturer, onetothreeyears.Anoffsettrencherornarrowbucketbackhoeareoccasionallyusedtoexcavate12inch-wide trenchesalongsidethewalltorelievesoilpressureandtoallowforfasterverticalrealignment. ADVANTAGES: Stabilizesandstraightenswallswithouttheneedforacompleteexcavationalongthelengthof theexteriorwall.Can,insomeinstances,reducethesizeofwallcracksandbringthewalltoamorever ticalposition.Lessexpensivethanwallreplacementorsidewallexcavations.Canpreventfurtherwall displacement. DISADVANTAGES: Notcapableofbringingwallbacktoafullyverticalposition,somethingwhichcouldonly beaccomplishedifthesoilontheoutsideofthewallwasremoved.Requiresexteriorexcavationforthewall plate.Wallanchorplatesareexposedontheinsidewallsurface. FIGURE3. HELICALWALLANCHOR 47

50 3. STABILIZE CRACKED AND INWARDLY BOWED FOUNDATION WALL BY USE OFHELICALSCREWANCHOR. Analternativetechniquetotheearthanchorincludestheuseofahelicalscrewanchor.Installedatinter valsalongawalldependingonthejobsiteconditions,helicalscrewanchorsaresimilarinconceptto earthanchorsdescribedabove,exceptthatthehelicalplateisapartoftheanchorroditself,andisscrewed intothesoilbankratherthanplacedinapit(Fig.3).Oncetheroddevelopstheappropriateresistance,a plateisplacedontheinsideofthewallandanuttightenedwithatorquewrenchtosecureandpossibly straightenthewall.ThetwolargestmanufacturersofhelicalsystemsareA.B.ChanceCo.andAtlasSystems, Inc.TheiranchorsareinstalledbycertieddealersthroughouttheU.S. ADVANTAGES: Stabilizesandmaystraightenwallswithouttheneedforcontinuousexcavations.Mayreduce thesizeofwallcracksbybringingwallstoamoreverticalposition.Lessexpensiveanddisruptivethanwall replacementorcontinuousexcavation. DISADVANTAGES: Maynotstraightenwallssignicantly;interioranchorplateisexposed. 4.REPAIRWALLCRACKSWITHCONVENTIONALGROUTINGTECHNIQUES. Ifcracksarenotexpandinginsizeandwaterpenetrationisnotanissue,conventionalgroutrepairsmay bepossible.Thelimitationsofgroutingsystemsareinherentintheirmaterialconsistencyasfairlystiff;dry mixestypicallyusedforrepairworkcannoteasilyowintocracks,especiallythinones.Mostcracksmust bechippedopenonthesurfaceforthepatchtobeeffective.Eveninthiscase,however,thepatchdepthis only1to2inches,andismorecosmeticthanstructuralinnature.Anumberofgroutingmaterialsareavail- ablethroughawidevarietyofsuppliers,includingconventionalportlandcementandsand,withorwith- outacrylicadmixturestoenhancethebondtoexistingmaterial,variousproprietarylowslumpdrypack mixtures,andfast-actinghydrauliccementsthatsetupfastandcanbeusedtoplugholesandwidecracks wherewaterseepageisaproblem.Inaddition,ber-reinforcedcements,calledsurface-bondingcements, aredesignedtostrengthenblockwallsandcanevenbeusedonbothsurfacestoformastructuralskinon wallslaiddrywithoutmortar. ADVANTAGES: Inexpensiverepairsthatdonotrequireahighdegreeofskilltocomplete. DISADVANTAGES:Essentiallysurfacerepairs,non-structural;exceptforhydrauliccements,willnotusually preventwaterpenetration.Willnotworkwherethereiscrackmovement. 5.REPAIRCRACKEDWALLWITHEPOXYINJECTIONS. Epoxyinjectionscanbeusedtorestorestructuralsoundnesswhenfoundationshavebeenstabilizedand FIGURE 4. EPOXYORURETHANEGROUTING 48

51 whencracksarenotgrowinginsize.Cracksasnarrowas0.002inchcanbebondedbytheinjection method.Thetypicaltechniqueinvolvesdrillingholesatcloseintervalsalongthecrackandinstallingtubes (ports)intheholesintowhichepoxyisinjectedunderpressure(Fig.4). ADVANTAGES: Aprovenandwidelyusedtechnique.Cancreateastructuralbondthatisstrongerthanthe concreteitself.Epoxygroutmaterialsareavailablefromawidevarietyofmanufacturers. DISADVANTAGES:Willnotpreventwallfromcrackingadjacenttotherepairiffurthermovementoccurs. Cannotbeusedifcracksareleakingwater.Whilemoistcrackscanbeinjected,waterorcontaminantsin thecrackwillreducetheeffectivenessoftherepair.Worksbestwithconcreteratherthanconcreteblock walls,becausethecoresintheblockreducethecontactarea.Expensive.Requiresskilledapplicators. 6.REPAIRCRACKEDWALLWITHURETHANEINJECTIONS. Urethanegroutsareusedtostopwaterinltrationandtollcracksinfoundationwallswhenthereissub stantialseepagethroughthewall.Urethanegroutsarealsoexible,whichmakesthemsuitableforrepairing crackswithlimitedmovement(upto 1/8 inchwithsomegrouts).Urethanegroutsarenotstructural(as epoxygroutsare)butwillservetohelpbondmaterialstogether.Groutsareeitherhydrophillic(whichchem icallyreactwithwaterandcandehydrateintheabsenceofwater)orhydrophobic(whichdonotdehy drate).Bothgroutsexpandtocreateadense,closed-cellfoamthroughwhichwaterwillnotpass.Specic applications should be reviewed with the manufacturers, some of which include the 3M Co., Green MountainInternational,PrimeResins,andtheDeNeefCo.Theapplicationofurethanegroutissimilarto thatofepoxy,pumpedthroughaseriesofinjectionportsthataredrilledtointerceptthecrack.Urethane sealantmanufacturersalsohavedevelopedfast-actingformulationsthatareapplieddirectlytoholesin concretetostopleaks. ADVANTAGES: State-of-the-artproductsusedincriticalsituationswherewaterandcrackmovementcondi tionsexist.Developedforcommercialprojectssuchasmunicipalwaterandsewerlines,tunnels,andother large-scaleprojects. DISADVANTAGES: Moreexpensivethanotherkindsofproducts.Nonstructural.Requiresskilledapplica torsandcarefulattentiontoinstallationinstructions.Notrecommendedforconcreteblockwalls,asexpan sionofurethanemaycrackblock. FURTHER READING Causes,EvaluationandRepairofCracksinConcreteStructures,publication244.1R-93,American ConcreteInstitute,1993. ConcreteRepairandMaintenanceIllustrated,PeterH.Emmons,R.S.Means,1993. ConcreteRepairGuide,ReportofACICommittee546-R97,AmericanConcreteInstitute. GuideforEvaluationofConcreteStructuresPriortoRehabilitation,publication364.1R-94,American ConcreteInstitute,1994. PreventingBuildingJointSealantFailures,ConcreteTechnologyToday,VOL.15,NO.2,PCA(1994). WhosWhoinConcreteRepair:MembershipDirectory,InternationalConcreteRepairInstitute,October 1995. PRODUCT INFORMATION W.R.Bonsal8201ArrowridgeBoulevard,Charlotte,NC282241148;8003340784 3MConstructionMarketsDivision,3MCenterBuilding,2254508,St.Paul,MN551441000; 8004801704 A.B.ChanceCompany,210NorthAllenStreet,Centralia,MO65240;5736828414 AtlasSystems,Inc.,3114WeatherfordRoad,Independence,MO64055;8003259375;www.atlassys.com Abatron,Inc.,550195thAvenue,Kenosha,WI,53144;8004451754 DeNeefConstructionMaterials,P.O.Box1219,Waller,TX77484;4093729185 49

52 GreenMountainInc.,P.O.Box97,Waynesville,NC28786;8009425151 GRIP-TITEManufacturingCo.,Inc.,P.O.Box111,Winterset,IA502730111;5154621313 PrimeResins,2381RockawayIndustrialBoulevard,Conyers,GA30207;8003217212 9.2 COATINGSANDFINISHES ESSENTIAL KNOWLEDGE Surfacetreatmentsforconcreteandconcreteblockwallsrepelwater,whichhelpstocontrolexteriorsurface stainingaswellasthemigrationofwaterthroughthewall,whichcanleadtoeforescence,staining,mold, andotherproblemsoninteriorsurfaces.Ingeneral,exteriorsurfacetreatmentsshouldallowforvapor transmissiontoensurethathumiditywithinthewallcanescape.Treatmentsthatareimpermeabletowater vaportendtofailbyblisteringandpeelingwhenmoisturebuildsupbehindtheexteriorsurfaces.(Special waterretardingcoatingsarediscussedinChapter5:DampproongandWaterproong.) Typical interior coatings include a wide variety of latex paints that use polyvinyl acetate as a binder.Thesepaintsarenotsubjecttoweatheringandarelessexpensivethanexteriorvinylacrylicpaints. Mostexteriorcoatingscanbeusedoninteriorapplications.Asisthecasewithallpaints,manufacturers recommendationsastosurfacepreparationsandapplicationsshouldbefollowedcarefully.Manufacturers estimatethatupto80percentofpaintfailuresareduetoimpropersurfacepreparationandapplication. Cleartreatments,whichcanbeusedtoenhancethewaterresistanceofwallswithoutsiginicantly alteringtheirappearance,aremadewitheithersilicone,silicateoracrylicresins.Epoxypaintsareusedin someinteriorwallandoorcommercialapplications,suchasinschoolsandhospitals,wherecorrosive chemicalsarepresentorhightrafcisanticipated,butarenotnormallyusedinresidentialapplications. TECHNIQUES, MATERIALS, TOOLS 1.APPLYCEMENTITIOUSCOATINGS. Cementitiouscoatingsincludeconventionalpargingandstuccocoatings,andspeciallyformulatedcement- basedproductsthatincludelatexbindersandotheradditivesthatenhanceperformance.Includedinthis categoryaresurfacebondingcementsmeetingASTMC887requirementsthatcontainglassberreinforce mentsthatcanstrengthenwalls. ADVANTAGES: Canchangecolorandtextureofexistingwall;canenhancewaterresistance;berreinforce mentsenhancestrength. DISADVANTAGES: Subjecttocrackinganddelaminationduetoweatheringandexpansionandcontraction ofwalls. 2.APPLYELASTOMERICCOATINGS. Anumberofmanufacturersproduceelastomericpolymercoatingsthatareformulatedtobridgestatic cracksup to 1/16 inch.Theseproductsareoftenusedasthenalcoatingonexteriorinsulationandnish systems(EIFS)andcanbeapplieddirectlyonconcreteandconcreteblockwalls.Thesecoatingsarealso used in conjunction with other brush- or trowel-applied elastomeric underlayment products that ll cracksupto1/4 inch. ADVANTAGES:Canchangecolorandtextureofexistingwall;cancoverandprotectexteriorsurfacessub jecttodeteriorationfromexpansionandcontraction. DISADVANTAGES: Signicantlymoreexpensivethanothercoatings. 3.APPLYPAINTCOATINGS. Thecurrentlypreferredexteriorpaintsarelatex,breathable,water-basedpaints.Latexpaintstypicallycome withacrylicorpolyvinylacetatebinders.Paintswithall-acrylicbindersarerecommendedforexterioruse 50

53 astheyhavethegreatestdurabilityandexibility.Mostpaintmanufacturersofferavarietyofcrackllers thatcanbeappliedbeforethenishpainttosmoothoutsurfaceirregularitiesinwalls.Alkydpaintsuse chemicalcompoundsmadefromvegetableoilandsyntheticresinsasbindersandaremoredifcultto applyandcleanupthanwater-basedlatexpaints.Theyarealsoadverselyaffectedbyalkalinesurfaces, especiallynewconcreteandconcreteblockconstruction.Recentlydevelopedacrylicpaintshaveanumber ofsuperiorcharacteristictoalkydpaints,includingeasierworkability,betterbreathability,exibility,color retention,resistancetochalking,andbetterresistancetomildew. ADVANTAGES: Canaltercolorandsurfacetexturewithuseofaggregateadditives;canincreasewaterresis tanceofwall;relativelyeconomical. DISADVANTAGES: Willnotbridgeactivecracks;requireson-goingmaintenanceandrenewal. FURTHER READING PaintingConcrete, 15134,PortlandCementAssociation,1992. PreventingMasonryFailuresWithProperCoatingChoices,TomSmead,ConstructionSpecier,July 1996,pp.4853. SpecifyingQualityArchitecturalPaints,WalterJ.Gozdan,ConstructionSpecier,July1996,pp.4447. WaterRepellentsforConcreteMasonryWalls,TEK19-1,NationalConcreteMasonryAssociation,1995. PRODUCT INFORMATION W.R.BonsalCompany,8201ArrowridgeBoulevard,P.O.Box241148,Charlotte,NC282241148, 8003340784. Sherwin-WilliamsCompany,101ProspectAvenueN.W.,Cleveland,OH44101;8003218194. 51

54 APPENDIX PROFESSIONAL ASSOCIATIONS & RESEARCH CENTERS AMERICANCONCRETEINSTITUTE AMERICANUNDERGROUND P.O.Box9094 CONSTRUCTIONASSOCIATION FarmingtonHills,MI483339094 51111thAvenueS. 8108483700 Suite248 www.aci-int.inter.net Minneapolis,MN55415 6123395403 AMERICANPLYWOODASSOCIATION P.O.Box11700 AMERICANWOODPRESERVERSASSOCIATION Tacoma,WA984110700 3246FallCreekHighway 2065656600 Suite190 www.apawood.org Granbury,TX760497979 8173266300 AMERICANPORTLANDCEMENTALLIANCE 1225IStreetNW. AMERICANWOODPRESERVERSINSTITUTE Suite300 2750ProsperityAvenue Washington,DC20005 Suite550 2024089494 Fairfax,VA220314312 7032040500 AMERICANSOCIETYFOR [email protected] CONCRETECONSTRUCTION P.O.Box9058 BUILDINGSEISMICSAFETYCOUNCIL FarmingtonHills,MI483339058 NATIONALINSTITUTEOFBUILDINGSCIENCES 8108483710 1201LStreetNW. www.ascconc.org Washington,DC20055 2022897800 AMERICANSOCIETYFORTESTING [email protected] ANDMATERIALS 100BarrHarborDrive CANADAMORTGAGEAND WestConshohocken,PA194282959 HOUSINGCORPORATION 6108329500 HOUSINGINFORMATIONCENTER www.astm.org 700MontrealRoad Ottawa,ON,CanadaK1A0P7 AMERICANSOCIETYOF 6137482367 HEATING,REFRIGERATIONAND www.cmhc-schl.gc.ca AIRCONDITIONINGENGINEERS 1791TullieCircleNE. CANADIANCONSTRUCTION Atlanta,GA30329 MATERIALSCENTRE 4046368400 INSTITUTEFORRESEARCHIN [email protected] CONSTRUCTION NATIONALRESEARCHCOUNCIL BuildingM24,MontrealRoad Ottawa,ON,CanadaK1A0R6 6139936189 52

55 CELLULOSEINSULATION HOMEVENTILATINGINSTITUTE MANUFACTURERSASSOCIATION DIVISIONOFTHEAIRMOVEMENT 136SouthKeoweeStreet CONTROLASSOCIATION Dayton,OH45402 30WestUniversityDrive 5132222462 ArlingtonHeights,IL60004 8473926009 CONCRETEFOUNDATIONSASSOCIATION 107FirstStreetW. INSULATINGCONCRETEFORMSASSOCIATION POBox204 960HarlemAvenue,Suite1128 MountVernonIA52314 Glenview,IL60025 3198956940 8476579730 CONCRETEREINFORCINGSTEELINSTITUTE INTERNATIONALCONCRETE 933N.PlumGroveRoad REPAIRINSTITUTE Schaumberg,IL60173 1323ShepardDrive,SuiteD 8475171200 Sterling,VA201644428 www.crsi.org 7034500116 CONCRETESAWINGAND INTERNATIONALMASONRYINSTITUTE DRILLINGASSOCIATION 81515thStreet,NW,Suite411 6089FrantzRoad Washington,DC20005 Suite101 2027833908 Dublin,OH43017 6147892252 INTERNATIONALREMODELING www.csda.org CONTRACTORSASSOCIATION 17SouthMainStreet CONSTRUCTIONSPECIFICATIONSINSTITUTE E.Granby,CT06026 601MadisonStreet 8009374722 Alexandria,VA22314 www.remodelingassociation.com 7036840300 www.csinet.org THEMASONRYSOCIETY 2619SpruceStreet,SuiteB COUNCILOFAMERICANBUILDINGOFFICIALS Boulder,CO803023808 5203LeesburgPike 3039399700 Suite708 FallsChurch,VA22041 NAHBREMODELORS COUNCIL 7039314533 120115thStreet,NW www.cabo.org FourthFloor Washington,DC20005 2028220212 www.nahb.com 53

56 NAHBRESEARCHCENTER PORTLANDCEMENTASSOCIATION 400PrinceGeorgesBoulevard 5420OrchardRoad UpperMarlboro,MD20774 Skokie,IL600771083 8006388556 8479666200 www.nahbrc.org SEALANT,WATERPROOFINGAND NATIONALASSOCIATIONOFTHE RESTORATIONINSTITUTE REMODELINGINDUSTRY 3101Broadway 4900SeminaryRoad KansasCity,MO64111 Suite320 8165618230 Alexandria,VA22311 www.swrionline.org 7035751100 www.nari.org SOUTHERNFORESTPRODUCTSASSOCIATION POBox641700 NATIONALCONCRETEMASONRYASSOCIATION Kenner,LA700641700 2302HorsePenRoad 5044434464 Herndon,VA201713499 7037131900 SOUTHERNPINECOUNCIL www.ncma.org P.O.Box641700 Kenner,LA700641700 NATIONALMULTIHOUSINGCOUNCIL 5044434464 1850MStreetNW.Suite540 www.southernpine.com Washington,DC200365803 2029742300 STRUCTURALINSULATEDPANELASSOCIATION www.nmhc.inter.net 1511KStreetNW.Suite600 Washington,DC20005 NATIONALREADYMIX 2023477800 CONCRETEASSOCIATION 900SpringStreet SUMPANDSEWAGEPUMP SilverSpring,MD20910 MANUFACTURERSASSOCIATION 3015871400 POBox298 Winnetka,IL60093 NATIONALTECHNICALINFORMATIONSERVICE 8475599233 USDEPARTMENTOFCOMMERCE 5285PortRoyalRoad,Springeld,VA22161 SUPERIORGUNITE/SHOTCRETEASSOCIATION 8005536847 12306VanNuysBoulevard www.ntis.gov LakeViewTerrace,CA91342 8188969199 NORTHAMERICANINSULATION MANUFACTURERSASSOCIATION 44CanalCenterPlaza,Suite310 Alexandria,VA22314 7036840084 www.naima.org 54

57 THEREHABGUIDE VOLUMEONE: FOUNDATIONS VOLUMETWO: EXTERIOR WALLS VOLUMETHREE: ROOFS VOLUMEFOUR: WINDOWS AND DOORS VOLUMEFIVE: PARTITIONS, CEILINGS, FLOORS AND STAIRS VOLUMESIX: KITCHENS & BATHS VOLUMESEVEN: ELECTRICAL/ELECTRONICS VOLUMEEIGHT: HVAC VOLUMENINE: SITE WORK U.S.DepartmentofHousingandUrbanDevelopment Washington,DC204106000 OfcialBusiness September1997 PenaltyforPrivateUse,$300

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