GREA-2P-27-3G-6xE — Gravel-roof reinforced restoration system

GREA-2P-27-3G-6xE is a Western Colloid specification for gravel roofs, revised 10/20 and headed Glas-Shield fluid applied reinforced roof system. It is classified as recover, gravel / rough surface, with a 1 ply polyester and glass fiber roving reinforced membrane and a 1 ply polyester / acrylic reinforced surface.

It is a cold process method to upgrade existing gravel roofing. As a reinforced liquid-applied roofing system, it is water based and has very low odor, with polyester fabric and fiber glass strands as reinforcement. The finish is a highly reflective elastomeric coating.

The manufacturer's specifications index files this system in the gravel category of the Glas-Shield line, under recover gravel surface, with #298 Emulsion and ElastaHyde Acrylic White as its products.

Eight numbered items make up the assembly, with amounts per 100 square feet and approximate dry weights.

• 0. Fill coat: #298 Emulsion, 12 gallons or as needed, 45 pounds.
• 1. Base coat: #298 Emulsion, 6 gallons, 23 pounds.
• 2. Polyester fabric, 1 ply, 2.5 pounds.
• 3. Top coat: #298 Emulsion, 9 gallons, 35 pounds.
• 4. Chopped glass fiber roving mixed into the top coat emulsion, 3 pounds.
• 5. Base coat: ElastaHyde, 3 gallons, 21 pounds.
• 6. Polyester fabric embedded in the ElastaHyde, 1 ply, 2.5 pounds.
• 7. Surface and reflective coating: ElastaHyde White Acrylic, 3 gallons, 21 pounds.

Total system dry weight is 108.0 pounds per 100 square feet, or 153.0 pounds with the fill coat. Approximate total dry thickness is 175 mils, with the fill coat not included.

The assembly meets California Title 24, LEED (USGBC) and Energy Star criteria. Publications forming part of the specification are ASTM, Western Colloid details, drawings and notes, ENERGY STAR guidelines for roof coatings, the Cool Roof Rating Council, Title 24 and LEED.

The fabric is Western Colloid T325 at 2.75 ounce soft or T272 at 3.0 ounce soft. The fiber glass roving is a continuous strand roving designed for chopped glass spray guns.

• WCP-SS (T325, Standard Soft Finish): 2.75 to 3.0 ounce per square yard, tensile 40.0 pounds, elongation 61 percent, burst strength 102.2 pounds, trapezoid tear 19 pounds. The soft finish conforms on semi-smooth or rough surfaces and works over vacuumed, spudded or filled gravel. Rolls are 10 square (40 inch by 324 feet).
• WCP-HS (T272, Heavy Soft): 3 ounce per square yard, 0.025 inch thick, tensile 57 pounds, elongation 61 percent, burst strength 176 pounds. It conforms on cap sheet, smooth surface and filled or spudded gravel.

#298 is the asphaltic bentonite clay emulsion for the fill, base and top coats. It is a waterproofing compound and surface coating that cures to a flexible film. It is supplied in 5 gallon and 55 gallon drums, totes and bulk. Permeability runs from 0.0 to 2.0 depending on thickness.

Where the fabric surface has been top coated with asphalt emulsion, or on chopped glass and emulsion systems, #970 A2A Bonding Primer may be required. It is a clear water based acrylic primer for adhesion of acrylic coatings to smooth asphalt products.

ElastaHyde #720 ARC supplies both the base and the surface layer. It is applied by roller, brush or spray, and high pressure airless spray is the preferred method. A quick set formulation exists. Coverage is 75 to 100 square feet per gallon per coat, and the weight is about 11.5 to 12 pounds per gallon.

Initial solar reflectivity is 84 percent and initial thermal emittance is 89 percent, with an SRI of 106 initial and 93 aged. It is Class A under U.L. 790 and ASTM E108 when dry. Wet adhesion to emulsion is above 10 pli and dry adhesion is above 17 pli.

#800 Elastic Cement is used in a three course method, with the first coat about 1/8 inch thick, polyester fabric embedded wet and a second coat over it. A single coat should stay under 3/16 inch because a skin can form. Application starts at 50 degrees F and rising. It adheres to asphalt emulsion, wood, metal and masonry without special primers, while new glazed asphalt roofs are primed with #970.