b"intervals aroundthe building to cut down trafficontheroof.Thiswasimpossible andthethreehoistingareasselectedinvolvedanaveragehaulof1200feeton the roof cop, almost a quarter of a mile. Theremoval of the mechanical equipment, vents and other roof projections, left asurfacepockmarkedwithholes-over 300of thembut madeit easyor rather easier comove a gravel scraper equipped with cutters around the roof surface, cutting it into 3 foot squares, for easy lowering from the 65 foot high roof to waiting dump trucks at ground level. Specialchutesweremanufacturedin the Tri-Stare sheer metal shop to move the debris. To accommodate the 3 foot sections of roofing, the chutes of galvanized metal were made 4 feet square and 10 feet long, withmeans for attachment to each other. Ahalf-dozenofthese,hookedtogether providedaswiftdescentoftherear-off piecestothewaitingtrucks. Powerbroomswereusedtosweep up the loose gravel after which it was loaded into powered wheelbarrows and driven to thechutes.Damageddeckmaterialwas removed, repaired where possible andreplaced when necessary. Over the clean reconstructeddeckavaporsealcomposed Illustration at top shows thetype of poweredof a30lb.asphalt feltwas appliedfolcartandtrailerusedtomovetheinsulation. Bottompictureshows theequipmentusedtolowed glass fiber insulation and 4 plies of transport the tons of gravel over the new roof.15lb.feltand400lbs.ofgravelper reduced labor costs but undoubtedly aided in insuring jobcompletion in advance of the deadline. Few contractors make money on rear-off jobs. This hasbeenresponsibleformost contractorssellingareroofjoboverthe existingroofing.Insomestarescityofficials got alarmed at the number of roof coveringsaddedtoweatheredroofsthat lawswerepassedrequiringacomplete rear-off after the third reroofing. Tri-Statehasspecializedintear-offs, selling prospectsonthe intelligentproposition that purring a new roof on cop of onethatfailedismerelyborrowing troubles.Halfoftheir contractsinvolve tear-offs. However,Tri-Starerakesnochances and in preparing a reroofing, rear-off estimate, unusual care is taken in checking the rear-off area, the total weight of the rearoff material, the labor in moving the debrisfromroof totrucksandthecost ofAbove:The oldroofingshowingssigns of the weatherbuffetingithadovertwentyyears. trucking the debris to a dump area.Acloselook attheroof surfacediscloses the It isimpossible, lookingat the surfacepattern of theroofdeck beneath theroofing. of an existing roof covering to determine howmuchmaterialisbelowthe surfacesample,measuresthickness,weighsit,square. or how many times it may have been re counts the felcplies,replacesthesampleThereroofingcrewsfollowedonthe roofed.TheTri-Stateestimatorisfur and waterproofsit with felcand plastic.heelsof thetear-offmen,coveringeach nishedwith aspecialtear-offkit,aboxVice-president Wheeler points out thatsection as it was cleared. In this way prowithhammer,hatchet,knife,feltanda tear off usually reveals the factors whichductionreached450squaresadayof plastic for sealing and even chemical soapcause roof failure, noting that in the casecompletedroof.Toservicetheroofers totakethegrimefromtheestimator'sof the Michoudroof,manyofthe con bulk hot asphaltwastruckedtothejob hands.creteslabswerecrackedandhadtobeand emptied intothree storage andheatWiththetoolstheestimatorcursareplaced.ing ranks in ascending capacities of 2,000, square foot sample thr0ugh gravel,felts,With such alarge roof it wouldhave4,000 and5,500 gallons. insulation down to the deck, removesthebeen ideal to spot hoistingequipment at(Continuedon page29) 14OCTOBER,1963"