b'MIDWESTRoofingConfradors Association,Inc.ModA.ldress: 1(100Dower & Lght Bldg. Knnsos(;14,Mis,011r.; ROBERT D. MARQmsEWING L.LUSK, JR.DALE CRAMPTONVICTOR R. NOTI1NGHAMRober!D.L4om PresidentSecretaryVice PresidentVice President 1724 Campbell Street2035 East 19th Street710 Division StreetBox 302ESrelo, 11 xcculivr Kansas City, MissouriKansas City, MissouriFort Smith, ArkansasGreeley,ColoradoGRnnd1-0848 Vol umeIXB U LLETINApril -Issue11965 FS SPLITTINGFAILURESOFBUI LT- UPROOByWilli amCoCullen NationalBur eauofStandards SUMMARY:AccordingtoarecentN tionalBurea uofStandardsstudy,the afollowinginnovat i onsi nroofdesignandr oofi ngprocedures shouldreducesplittingf a ilure sofbui l t=upr oofs : *Tapeinsulationj o i nt s o *Placelongdimensionofinsulationboardsparallel toshortdimensionofr oofo *Placeroofingwith"i nmachine"directionparallel tolongd i mensionofroof o *Useexpansionjoi nts =notstruct ural- inmembrane. *Useoptimum- strengt hadhesi vebondstoholdroof membranetoinsulation o Thesei nnovationscouldsavethena tionm llionsofdollars iannuallyo Asphaltandcoal -tarproduct s ithemostwidel yusedroofingmateria l si ntheUnitedStatestoday 9a ccountedforapproximat el ylo7billionsq ftofbituminousbuilt- uproofconstruc t ioni n1 963atacostofabout450 milliondollarsoSuchroofingshouldha veal i f eexpec t ancyof20years ormore ;howeverjthislifespanisnotal waysa ttainedbecauseoffrequent prematurefailuresofoneormorecomponent si nthes ys t em. TheNationalBureauofStandardsI nst i tuteforAppliedTechnology (UoS oDepartmentofCommerce)conducts acontinuingpr ogramtoimprove . t heeffectiveuseofbuildi ngmaterial s.Inthi sprogram,arecentinvestigationsponsoredbytheArmy ~Navy 9andAirForcewasmadetodeterminethecauseofsplitting f ailure so fbui l t=uproofsandtodevisemeans t oreducetheinci denceofthesef a i l ures .Ther esultsofthestudyby W ll iamCoCullen( NBSMonograph89)showt hatspl i ttinginthewaterproof il ayer(membrane)i scausedbys t r e s sconce nt rat ionswhicharebuilt-up -ver- nsulationjoi n t sbythecumul at i vemovementofbot ht hei n~ulation o .,- i ~ MIDWE:ST "OOFINO CONT"ACTORS ASSOCIATION'