DDAA-2P-8xE — New-construction reinforced roof system

DDAA-2P-8xE is a Western Colloid all-acrylic roof system for new construction or re-roofing. Its title is New Construction or Re-Roof, Insulation/DensDeck Prime, Concrete, with a 2 ply polyester reinforced acrylic surface. The cold process, water based method installs a new membrane on approved combustible or non-combustible decks. It can be installed directly to concrete, or over concrete and wood decks using insulation and DensDeck Prime, or over existing membranes. The system has very low odor and a reflective elastomeric top surface. Listed criteria cover LEED (USGBC), California Title 24 and Energy Star, as well as U.L. Class A and Factory Mutual Standard 4470 Class 1. Wind uplift is 1-510 (FM) over DensDeck and 1-990 (FM) over concrete.

Six layers form the membrane. Approximate dry weights are per 100 sq. ft.

• Base coat of ElastaHyde: 3 gallons, 21 lb
• Polyester fabric, first ply: 2.5 lb
• Interply coat of ElastaHyde: 2 gallons, 14 lb
• Polyester fabric, second ply: 2.5 lb
• Top coat of ElastaHyde: 1.5 gallons, 10.5 lb
• Reflective surface coating of ElastaHyde White Acrylic: 1.5 gallons, 10.5 lb

Total system dry weight is 61.0 lb and approximate total dry thickness is 92 mils.

The insulation is rigid polyisocyanurate board with glass fiber felt facers, meeting ASTM C-1289 Type II, Class 1, Grade 2 (20 psi) or Grade III (25 psi). DensDeck Prime is a gypsum roof board with a primed fiberglass mat facer on one side, meeting ASTM C-1177. Boards are attached with INSTA STIK Quick Set Commercial Roofing Adhesive, a single-component polyurethane board adhesive applied in ribbons or full applications. Minimum ambient and surface temperature for the adhesive is 33 degrees F and rising, and 75 degrees F is the ideal application temperature.

Boards are adhered to the deck in line with the wind uplift rating and its ribbon spacing patterns. Maximum board size with board adhesives is 4 ft by 4 ft for insulation and 4 ft by 8 ft for roof boards. Boards are cut to fit around penetrations and projections, and tapered insulation follows the insulation manufacturer's shop drawings. Where two or more layers of insulation or roof boards are used, the joints are staggered at least 12 inches in both directions between layers. All DensDeck Prime joints, including terminations at penetrations, curbs and walls, are caulked and filled with #800 Elastic Cement or approved caulking. Gaps of 1/4 inch or more are three coursed with #800 and 4 inch polyester fabric.

The first ply is ElastaHyde at 3 gallons per 100 sq. ft. with a half-width polyester strip at the low edge and full-width sheets after it. The second ply is set in ElastaHyde at 2 gallons per 100 sq. ft. Each ply is lightly broomed to saturation and stops 2 inches above the cant. Pipe flashings, cones, exposed metal joints and flanges get #800 Elastic Cement and fabric in a three course method. Extra polyester plies go around drains and scuppers and wherever water ponds for more than 48 hours. The top and reflective coats follow at 1 1/2 gallons per 100 sq. ft. each, cross-hatched, with 24 hours of drying after the first. The result is a reinforced liquid-applied roof membrane over the board.

ElastaHyde 720 ARC has a 100 percent acrylic base and comes in white, gray and tan, with custom colors available. ElastaHyde 790 may be used in its place when the specifier recommends it. The coating repels water, but it is not recommended on surfaces that pond water for more than 72 hours without reinforcement, and it is not recommended over wood shingles or untreated wood. #800 Elastic Cement is a water-based, elastomeric flashing, patching and sealing compound made with acrylic rubber resins, inert mineral pigments and non-asbestos fibers. It is non-flammable, low odor and not DOT regulated.

The air and surface temperature during application is a minimum of 55 degrees F and rising. Containers stay tightly closed when not in use, and materials stored temporarily on the roof sit in approved areas within the live load limit.

• Polyester fabric: Western Colloid 2.75 ounce firm or 3.0 ounce soft stitchbonded polyester, supplied in various widths, used to reinforce asphalt emulsion, acrylic coating and flashing materials
• #8000 All Weather Elastic Cement: a solvent-based white sealant that sets the flange of a new or replaced pipe jack, and a stated alternative to #800 where more immediate water resistance is needed

• Elongation: above 250 percent initially and above 175 percent after weathering (ASTM D2370)
• Tensile strength: above 250 psi (ASTM D2370)
• Wet adhesion over emulsion: above 10 pli, dry adhesion above 17 pli (ASTM D903)
• Tear resistance: above 100 lbf/in (ASTM D624)
• Low temperature flexibility: Pass at 15 degrees F, 1/2 inch (ASTM D522)
• Permeance: below 15 (ASTM D1653)
• Water swelling: below 20 percent (ASTM D471)
• Fungi resistance: no growth (ASTM G21)
• Dirt pick-up resistance: very good

The white coating is standard, and California Tan (a light tan) and Platinum Gray (a light gray) are also offered, with custom colors available. It is listed by the Cool Roof Rating Council. White, California Tan and Platinum Gray meet California Title 24 and are the colors named for ENERGY STAR. A Quick Set (QS) formulation is made for jobs where damp, wet or rainy weather is expected before the coating fully dries. The coating comes in 5-gallon pails, 55-gallon drums, totes and bulk tankers.

Recommended uses are conventional and modified built-up roofs, existing spray polyurethane foam roofs, and the topcoat of Western Colloid fluid applied reinforced roofing (FARR) and metal roof systems. The coating is not recommended over wood shingles or untreated wood, and it is not recommended on surfaces that pond water for more than 72 hours without reinforcement.

#800 Elastic Cement is a heavy-bodied compound of acrylic rubber resins, inert mineral pigments and non-asbestos fibers. It is applied by brush or trowel, and brushing is preferred. The surface can be dry or damp but not wet, and clean of dirt, dust and oil. The cement bonds to asphalt emulsion, wood, metal and masonry without special primers, and new glazed asphalt roofs take #970 primer first. Rusted metal is cleaned and primed with #900R Rust Primer. The cement is non-flammable, low odor and not DOT regulated, and equipment is cleaned with water.

• White (#800W) or black (#800B); the black dries faster in cold weather
• Packaging: 5-gallon pails
• Total solids: 65 to 70 percent by weight