RETROFIT Improvements MakingHomesSafer inDisasters

Hazards

Februar y 2012 Working Draf t w w w.toolbase.org

Additional stud

Lateral bracing

Compression blockingRafter

Truss bottom chord

Lateral bracing (6’ minimum)

Compression blocking

Double top plate

Gable end trussbottom chord

Gable end stud

Purpose•Topreventrooffailurefromhighwinds

Benefits•Preventsrooffailure•Strengthensthebuildingenvelopeagainstpenetrationbywindandwater

Retrofit Opportunity•Thisretrofitcanbeperformedatanytimeiftheatticframingisexposed

•Rooforsidingreplacementproject

IllustrationsRetrofitOption 1:Diagonal bracing

SummaryBecausegableroofspresentalargewallsurfacetotheelementsatthehighestpartofthehousewherewindsarestrongest,gableroofsaremoresusceptibletodamagefromhighwindsthanhiporflatroofs.Ifthegableendisnotadequatelybracedtoresistthewind,thegableendwallcancollapseunderthewind’sforce,leavingtherestoftheroofsusceptibletoupliftandthehouseopentotheelements.Inadequatelybracedgableendsareacommoncauseofmajordamagetostructuresandtheircontentsinstorms.Iftheroofingisbeingreplaced,improvetheattachmentoftheroofsheathingbyinstallingfastenersat4”spacingthroughoutthesheathingforthefirstfourfeetofroofareafromallroofedges.Installfastenersat6”spacingotherwise.Ifthereisanoverhanggreaterthan12”atthegableend(rake),anditisframedasaladderandattachedtothesideofthehouse,itisbesttoremoveit.Itmaybepossible,however,toreinforcetheconnectionbyinstallingalagboltfromtheattic,throughthegableendtopchordandwallsheathing,intothe2x4oftheladderframe.Rakeoverhangsinhighwindareasshouldbeconstructedasoutriggerstiedbackintotheroofsystemfortwicethelengthoftheoverhang,orasfaraspossible,andsecuredattheendwithtiedownhardware(e.g.joisthanger).Gableendswillbesimilarlyconstructedinbothtruss-framedandconventionalrafter-framedroofs,thusaddedbracingdetailswillbesimilarforeitherroofsystem.Rooftrussedsystemswilltypicallyhavepermanentlateralbracinginstalledperpendicularlycrossingthecenterofwebsexceeding8’inlength.Rafterswilltypicallyhavecollartiesandpurlinsinthesameplaneastherafters.Thepermanentlateralbracingofbothsystemsisalsoprovidedbytheroofsheathingandceilingdrywall.Thereareseveral“Do-It-Yourself”approachestogableendbracingforthehandyhomeownerwhoisabletogainaccesstothegableendthroughtheattic,andthecostofmaterialsforthisretrofitisunder$100.Otherwise,consultacontractortoincorporatethisandothersafetyfeaturesintoyournextremodelingproject.

Gable End BracingFloodWind Rain Seismic SnowFire

2x4 Gable bracing

Option 2:Gable end bracing

Februar y 2012 Working Draf t w w w.toolbase.org

Potential Damage

Key Steps •Bracinggablewallsinanaccessibleatticisamoderatelyeasytaskandcanbea“Do-It-Yourself”jobforthenovicewithpatience.

• Inspecttheatticforadequateroofsystemandgableendbracing.• Ifyouareunsurewhetheryourgableendroofisadequatelybraced,haveahomeinspectororlicensedcontractortakealookandreporttoyou.

•Putdownwalkplanksalongthebottomchordsorceilingrafterstopreventdamagetotheceilingbelow.•Yourcontractormayhaveadditionalideasonhowtoimprovethesafetyofyourhome.•Formoredetailsaboutthisretrofitimprovement,pleaserefertothelistofResourcesinthesectionbelow.

ResourcesFEMA,Against the Wind: Protecting Your Home from Hurricane Wind Damagehttp://www.fema.gov/library/viewRecord.do?id=1641FEMA,Home Builder’s Guide to Coastal Constructionhttp://www.fema.gov/library/viewRecord.do;jsessionid=E34B1F94FFFA4B12C81995C6DC000644.Worker2Library?fromSearch=fromsearch&id=2138FloridaDivisionofEmergencyManagement,Hurricane Retrofit Guide: Gable End Bracinghttp://www.floridadisaster.org/hrg/content/roofs/bracing.asp

Photo:NAHBResearchCenter