SM-1P-14-3G-3E — Acrylic-surfaced reinforced roof system

SM-1P-14-3G-3E is a Western Colloid fluid applied reinforced roof system, revised 10/20. The classification is recover, smooth surface / cap sheet, 1 ply polyester and glass fiber roving reinforced, with an acrylic surface. The 3E in the code refers to the ElastaHyde white acrylic surface.

The assembly upgrades existing BUR, Mod Bit, EPDM, TPO and Hypalon. This liquid-applied roofing method is cold process, water based and low in odor, and it uses fiber glass strands as well as polyester fabric.

The manufacturer's specifications index files this system as a cap, single-ply, smooth roof system under the Glas-Shield line, with #298 Emulsion and ElastaHyde White Acrylic as its products.

The system has five items, per 100 square feet.

• #298 base coat of 5 gallons (19 pounds dry).
• Polyester fabric: 1 ply, 2.5 pounds.
• #298 top coat of 9 gallons (35 pounds dry).
• Chopped glass fiber roving (3 pounds) in the top coat emulsion layer.
• Reflective surface coating: ElastaHyde White Acrylic, 3 gallons, 21 pounds dry.

The assembly weighs 80.5 pounds dry in total and has an approximate dry thickness of 145 mils.

U.L. Class A, California Title 24, LEED (USGBC) and Energy Star criteria are all met by the assembly. The coating itself is Class A when dry under U.L. 790 and ASTM E108, and is non-flammable wet.

The surface coat ElastaHyde #720 ARC is an elastomeric 100 percent acrylic.

• Elongation: above 250 percent initially and above 175 percent after weathering (ASTM D2370).
• Tensile strength: above 250 psi (ASTM D2370).
• Tear resistance: above 100 lbf/in (ASTM D624).
• Low temperature flexibility: pass at 15 degrees F over a 1/2 inch mandrel (ASTM D522).
• Water swelling: below 20 percent (ASTM D471).
• Permeance: below 15 (ASTM D1653).
• Viscosity: 100 to 110 KU (ASTM D562).
• VOC: 10 actual and 20 regulatory.

Dirt pick-up resistance is rated very good. It is not recommended over wood shingles or untreated wood surfaces, nor on surfaces that pond water for more than 72 hours without reinforcement or other precautions.

Application temperature is 50 to 100 degrees F ambient. A two coat cross hatch method puts the second application at right angles to the first, with a heavier coat around vents and seams. Total use is 2 1/2 to 6 gallons per 100 square feet depending on the specification and surface. Equipment cleans up with soap and warm water.

Smooth asphalt, emulsion or non-granulated modified bitumen surfaces take a coat of #970 A2A Primer first. The coating should not meet heavy dew, rain, moisture or freezing within 48 hours of application.

Fabric is W26/T326 at 2.75 ounce firm or T272 at 3.0 ounce soft stitchbonded polyester, and the roving is designed for chopped glass spray guns. #850 SWS walkway coating contains an aggregate and provides a textured non-slip walking surface on smooth and coated roofs. #970 A2A Bonding Primer goes between asphalt emulsion and acrylic coatings.

#800 Elastic Cement has total solids of 65 to 70 percent by weight and a tack free time of 1 hour. It is brushed or troweled at about 20 square feet per gallon for the first course, a fabric is embedded while the first course is wet, and a second course follows at 1/16 inch. The finished membrane is about 1/8 inch dried.