GREA-3P-24-6xE — Gravel-roof reinforced restoration system

GREA-3P-24-6xE is a Western Colloid fluid applied reinforced roof system written for recovering gravel and rough-surfaced roofs. The title of the system reads Recover Gravel / Rough Surface, 2 Ply Polyester Reinforced Membrane and 1 Ply Polyester / Acrylic Reinforced Surface. It sits in the Western Cool Roof Systems line of commercial roof coating systems. The assembly is a cold process, water based method of upgrading an existing gravel roof. It has very low odor. The reinforcement is polyester fabric together with fiber glass strands, and the top surface is a reflective elastomeric coating. The membrane carries three polyester plies. Two are set in #298 asphalt emulsion and the third is set in ElastaHyde acrylic. The assembly is listed against California Title 24, LEED (USGBC) and ENERGY STAR criteria.

The components are listed in installation order with approximate dry weights per 100 sq. ft.

• Fill coat of #298 Emulsion, as needed at 10 to 12 gallons: 12 gallons, 45 lb
• Base coat of #298 Emulsion: 6 gallons, 23 lb
• Polyester fabric, first ply: 1 ply, 2.5 lb
• Interply coat of #298 Emulsion: 6 gallons, 23 lb
• Polyester fabric, second ply, set in emulsion: 1 ply, 2.5 lb
• Base coat of ElastaHyde: 3 gallons, 21 lb
• Polyester fabric set in ElastaHyde: 1 ply, 2.5 lb
• Surface and reflective coating, ElastaHyde White Acrylic: 3 gallons, 21 lb

Total system dry weight is 140.5 lb with the fill coat. Total system dry thickness is approximately 165 mils without the fill coat and approximately 257 mils with it.

Surfaces that are very rough or have embedded gravel receive a fill coat of #298 emulsion at 10 to 12 gallons per 100 sq. ft., or as needed to fill the gravel. Gravel of 1/4 to 3/8 inch needs 10 gallons of fill and gravel of 1/2 inch needs 12 gallons. Larger gravel may need more, and spudded gravel may need less. The fill coat is approved by the manufacturer before the membrane goes on. Loose gravel, dirt, dust and debris are removed by vacuum, washing, sweeping or power blower. Valleys and ponding areas are washed and, where priming is needed, primed with #298 Asphalt Emulsion diluted 20 to 30 percent with water and applied vigorously with a brush. Valleys and ponding areas also receive an extra ply of polyester set in #298 before the membrane.

Blisters are cut out with a flat shovel, scraper or knife and repaired as a floating patch. Modified cap sheet is embedded in asphalt flashing compound, and its edges extend at least 6 inches past the widest point of the blister. Large splits are repaired the same way with modified cap sheet in asphalt flashing compound, and peel-and-stick modified cap or torch-applied APP cap are also named for repairs. Small splits and irregularities receive a three course repair with #800 Elastic Cement. The first coat goes on at 5 gallons per 100 sq. ft., about 1/8 inch thick, with one ply of polyester fabric brushed into the wet cement. A second coat follows at 4 gallons per 100 sq. ft.

The emulsion membrane begins with a coat of #298 at 6 gallons per 100 sq. ft. A half-width strip of polyester is embedded first at the low edge of the roof, then full-width sheets continue up the slope. A second coat of #298 at 6 gallons per 100 sq. ft. receives a full-width second ply. Each ply is lightly broomed to full saturation without wrinkles or voids and ends 2 inches above the cant. No top coat of #298 goes over the polyester. If excess emulsion or a top coat does end up on the fabric, #970 A2A primer is applied at 1/2 gallon per 100 sq. ft. after washing off asphaltic residue that could cause tobacco staining. The acrylic layer goes on once the emulsion has dried. It is applied early in the day, before the sun softens the emulsion surface. ElastaHyde 720 ARC at 3 gallons per 100 sq. ft. receives a full-width ply of polyester, and the layer cures at least 24 hours. The reflective coat is two applications of 1 1/2 gallons per 100 sq. ft. at right angles to each other, with at least 24 hours of drying after the first.

#298 Asphalt Emulsion is a clay-stabilized asphalt emulsion meeting ASTM D1227 Type III, made in a continuous colloid mill process without added surfactants or additives. It is also sold as Glas-Shield Waterproofing Compound. Its solids are 45 to 50 percent, its weight is 8.2 to 8.7 lb per gallon, it sets firm in 12 hours at 70 degrees F and 50 percent relative humidity, and its VOC is 0 actual and 0 regulatory. It is the waterproofing component of many UL Class A and Factory Mutual Class 1 roofing systems. Two polyester fabrics are named for the system. WCP-SS is the T325 stitchbonded fabric at 2.75 to 3.0 ounces per square yard. It has a soft finish with fewer stitches per inch and conforms well to semi-smooth or rough surfaces, including vacuumed, spudded or filled gravel. Its tensile average is 40.0 lb, elongation 61 percent, burst strength 102.2 lb and trapezoid tear 19 lb. It comes in 10 square rolls of 40 inches by 324 feet. WCP-HS is the T272 fabric at 3 ounces per square yard and 0.025 inch thick. Its tensile average is 57 lb, elongation 61 percent, burst strength 176 lb and trapezoid tear 16 lb. Roll sizes are 10 square at 40 inches by 324 feet, and 4, 6, 12 and 18 inch widths at 300 inches long.

Base flashing uses a 6 inch ply of polyester over the cant strip, set in ElastaHyde at 3 gallons per 100 sq. ft. per ply. Edge metal is nailed at 4 inches on center and stripped in with polyester fabric and #800 Elastic Cement. Where a gravel stop is replaced, a low or no rise metal edge takes its place. Pipe flanges are set in #8000 All Weather Elastic Cement, a solvent-based white sealant, and #800 is not used under a new flange. The finish is ElastaHyde White. The #720 ARC white carries CRRC product ID 0682-003 with initial solar reflectance 0.84 and thermal emittance 0.89, weathered values of 0.75 and 0.91, and SRI of 106 initial and 93 aged. The same coating is a 100 percent acrylic that meets ASTM D6083. Areas expected to see foot traffic can take two coats of #850 SWS walkway coating at 2 gallons per 100 sq. ft. each, which carries an aggregate for a textured non-slip surface. The result is a reinforced liquid-applied roofing membrane built from polyester plies set in wet emulsion and acrylic coating.