CRACKING IN GYPSUM DRYWALLSURFACES
Crackinginstucco,plasterandconcreteconstructionisacommonoccurrencethatistypicallynotonlytolerated,butisaccepted.Crackingingypsum drywallsurfaceshowever,isconsideredadefectinthesystemrequiringcompleteandexpertrepair.
Themostcommonareaforcrackingisinthecenterofthedrywalljointandiscommonlydefinedas“CenterCracking”.Whiletherearevariouscontributing factors,itcanbelogicallyarguedthattheoverwhelmingmajorityofthesecracksdonotoccurwithoutmovement.Suchmovementmayberelatedtothe gypsumsubstrateitselformorecommonly,tothestructuralcomponentsoverwhichtheboardisapplied.Theseverityofthemovementdeterminesthe extentofthecrack,rangingfromveryfine“hairline”defectstofissuresof1/8”ormore.
Thefunctionofadrywalljointiscosmetic,notstructural.Itisunderstoodthatacrackinthatjointisadefect,butthereisnostandardastohowmuch movementand/orforcethejointshouldwithstandpriortofailure.Itbecomesverydifficulttherefore,todeterminetheprimarycauseofthecrackandwho isresponsibleforrepaircosts.Forexample,becauseweacceptthefactthatmovementoccursinallstructures,thenextquestionishowmuchdoesthe structurehavetomovetoconsiderdrywallcrackingasa“structural”or“design”problemratherthana“drywall”problem?Itisquiteevidentthatevery crackindrywallisneithertheresultofdefectivedrywallfinishingproductsnorimproperapplicationofthoseproducts.
WhileHamiltoncannotinspecteachinstanceofcrackingnorprofesstoknowthecauseofeverycrack,wewillcontinueourresearchintominimizingthe problemsastheyrelatetoourproducts.Weinvitetheparticipation,advice,andinputfromallinterestedpartieswithinthedrywallindustryaswellas partieshavingexpertiseinstructureanddesign.Weparticularlyinvitetheconsiderationofallpartiestoeffectthatjobconditionsplayinexpansion, contractionandmovementwithintheconstructionprocessfromsoilcompactionthroughfinaldecoration.
Asaservicetotheindustrywehavepreparedtechnicalbulletinsregardingrecommendeddrywallapplicationandfinishingtechniques,whichshouldminimize cracking. Also available are recommendations regarding the repair of cracking by variousmethods.
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