Decks The deck is the base over which the built-up roofing, or insulation and built-up roofing is applied. Where the term “deck” is used in this manual without reference to insulation, it shall designate the surface over which the roofing material is to be applied. All decks shall be clean, smooth, dry, rigid and free of debris. Any deck defect shall be corrected before application of roofing materials. All decks shall be installed in accordance with the deck manufacturer’s specifications and shall be in compliance with Koppers requirements. If Koppers approves a deck as satisfactory to receive a Koppers roof, Koppers only reviews and approves the deck surface. It is the responsibility of the building designer and the deck manufacturer to provide for expansion, contraction and proper slope in a manner that will provide a stable base for the roofing; for support of maximum anticipated loads; secure attachments vertically and laterally; and the selection of the deck material and construction details including their ability to prevent drippage. Designers should take into account wind loads (both positive and negative pressures) and roof traffic conditions including mechanical equipment used for roof application. Decks must have sufficient strength to carry anticipated live and dead loads without excessive deflection or differential movement between panels which could rupture the roofing system. Metal decks shall not be lighter than 22 gauge (0.75mm), and the installation shall comply with the Factory Mutual Loss Prevention Data Sheet 1-28 and local codes. Koppers supports the NRCA position concerning corrosion protection for steel roof decks recommended in their Bulletin #15 dated May 1991. The placing of conduits, bolt heads, etc., above the roof deck and below the roofing membrane is not recommended. All projections or openings in the deck should be completed prior to the application of the roofing system. For penetrations made after the roofing system is completed, provisions must be made to prevent bitumen drippage. Optimum attachment/adhesion to the structural deck is necessary for good roof performance. Where coal tar or steep asphalt is used as an adhesive, questionable decks may be tested for dryness and adhesion by pouring one pint of the bitumen, heated to application temperature, over a representative area or areas of the deck. The deck is not satisfactory if the bitumen foams or bubbles, or upon cooling to ambient temperature, it may be stripped clean of the deck. This test should be conducted in an area which simulates the most adverse deck conditions. When decks do not permit adequate adhesion, a primer or additional drying may be required. Koppers will not assume responsibility for deck defects, coal tar drippage or membrane slippage.  Return to General Requirements and Considerations for the Designer