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ROOF DESIGN CONSIDERATIONS —Where the Mean January Temperature(reference current Plywood/Oriented Strand Board(OSB) ASHRAE Fundamentals Handbook)is below 40OF(4.40C), —Plywood must be exterior grade,minimum 4 ply,and at least lightweight insulating concrete decks must be poured and 15/32' (12 mm)thi& roofed between April 1st and October 31st;this type of deck is unacceptable in Alaska. —OSB must comply with Structural 1 rating and be at least 716' —lightweight insulating concrete should not be poured during (11 mm)thick. rainy periods;deck areas that have frozen before they have —Tongue and groove edges. cured must be removed and replaced.Check decks for moisture —Adhesives should only be used with untreated plywood/OSB. content and dryness if exposed to precipitation prior to installation of roof membrane. —Surface of plywood/OSB should be dry to the touch with no visible liquid,snow or ice at the time roofing is installed. Loadmaster Decks —Moisture content not to exceed 16%. —Roof deck must be installed by a Loadmaster-approved contractor according to Loadmaster specifications. Sheet Metal —Min.25 gauge steel decking,15/1c"(22 mm)deep with'/z"(13 —Min.24 gauge steel. mm)thick mineral board top panel. —Min..032" (8 mm)aluminum. —Polystyrene or polyisocyanurate insulation is optional. —Corrugated panels require overlay of 15/32" (12 mm)plywood/ —Install only white or light colored membranes on Loadmaster oriented strand board or silicone-impregnated gypsum panel. Decks. —Consult a GAF Field Services Manager or Director for reroofing Gypsum Panel and re-covering requirements. —Min.'/z" (13 rum)thickness. Non-Acceptable Substrates —Underlying substrate must allow securement of flashing at prescribed spacing.Mechanical attachment to gypsum panels Note:The following are some examples of non-acceptable roof is not acceptable. substrates,but should not be considered a complete list.Please —Use of gypsum panel requires GAF Field Services Area Manager's call 800-766-3411 or consult with a GAF Field Services Manager or or Director's approval. Director regarding the suitability of unusual deck substrates. —Metal roof panels,unless secured to structural purlins —Transite roof panels ROOF DRAINAGE —Fiberglass roof panels Providing positive roof drainage is important.Standing water can result in deck deflection and possible structural damage. In addition,in the event of an opening through the roofing PARAPET WAIlS membrane,standing water can significantly worsen damage to the roof system,the building itself,and interior contents by providing Most common structural wall types are suitable substrates for the a reservoir of water ready to gravitate through the membrane installation of EverGuard®membrane flashing. opening.Providing structural slope in the deck assembly,installing a tapered lightweight cellular concrete overlay,installing a tapered insulation system,or adding additional drains are the most Brick/Block Masonry common methods of achieving positive drainage. —Standard-finish brick and concrete block with standard tooled National building codes generally require a minimum'/a:12 slope mortar joints. to drain in order to provide positive drainage and accommodate —Split-face block,textured block and brick,and deeply tooled deck irregularities.Although existing buildings may or may not mortar joints require a cementitious coating or plywood facing be required by code to achieve this degree of roof slope,providing to provide a smooth and even substrate surface. positive slope to drain remains an important design consideration. In situations where roof edge conditions,window/door height above the roof surface,parapet wall height,weep hole locations,rooftop Structural Concrete equipment mountings,or other factors prevent the installation of —Steel trowel,wood float,or removable form finish. a full slope-to-drain system,a combination of additional drain locations,tapered saddles,and crickets to direct drainage to drain —Ridges and other irregularities require grinding to provide a points should be considered. smooth and even substrate surface. Design and installation of roof drainage systems should comply with the International Energy Conservation Code(IECC)and the Stucco/EIFS International Plumbing Code(IPC). —Stucco finish and EIFS systems must be removed to the underlying substrate surface. 14