Ure-A-Sil

Ure-A-Sil is a fluid-applied roof restoration system from American WeatherStar for commercial flat roofs. It pairs a urethane base coat with a silicone top coat, so the system combines the adhesion of urethane coating with the UV and waterproofing performance of silicone coating.

The coating cures to a watertight, reflective membrane. It is used over the entire roof surface, for spot repairs and as supplemental protection on flashing. The system resists ponding water and is designed to counter freeze-thaw damage in northern climates.

The system is a silicone roof coating assembly on top of a urethane base. It is applied to built-up roofs, concrete, EPDM, modified bitumen, single-ply membranes (TPO and PVC) and spray polyurethane foam.

The system is installed in four steps over the existing roof substrate.

• Surface preparation. The roof is pressure washed to remove dirt, dust, debris and other foreign contaminants.
• Seams and details. All seams and flashing details are coated with Urethane Brush-Grade 522.
• Base coat. Aromatic Urethane 520 acts as a primer and base coat. Aromatic Urethane 508 is also named as the base coat developed for the Ure-A-Sil system.
• Top coat. Silicone 410 or High-Solids Silicone 412 forms the top coat.

The modified bitumen, smooth and gravel BUR and single-ply guidelines list both Aromatic Urethane 508 and 520, while the EPDM and concrete guidelines list Aromatic Urethane 520. A spunbound polyester fabric with a tensile strength of 35 psi and EcoCleaner 925 appear in every guideline. On built-up roofs a non-fibered asphalt emulsion roof surface leveler is added. It is black, has a viscosity of 8,000 to 15,000 cps and contains 51% ± 2% solids by volume.

Aromatic Urethane 520 is a high-solids, single-component, moisture-cure polyurethane elastomeric coating. It was developed to protect sprayed-in-place polyurethane foam roofing and is also used on EPDM, modified bitumen, single-ply membranes, wood, concrete, masonry and most metals. Once cured, it resists lateral movement and shear and allows normal expansion and contraction.

• Solids by volume: 70% ± 2%
• Elongation: 475% ± 50%
• Tensile strength: 715 psi ± 25 psi
• Viscosity: 2,000 cps
• Weight: 9.2 lbs. per gallon; flash point 80°F
• Hardness: 65 Shore A
• Permeability: 0.02 perms; water absorption 2.4%
• Dry-to-touch: 6 hours; tack-free: 8 to 12 hours; recoat: 12 to 16 hours
• Service temperature range: -50°F to 200°F
• Shelf life: 18 months
• Color: silver
• Packaging: 5 gallons and 55 gallons
• Clean up: xylene

It is applied with medium nap rollers, soft brushes or conventional airless spray equipment to clean, dry, sound surfaces. Minimum application temperature is 40°F, and it is stored dry between 40°F and 100°F. An adhesion test of the Aromatic Urethane 520 base coat on the existing substrate is recommended.

Aromatic Urethane 508 is a high-solids, single-component, moisture-cure polyurethane base coat for commercial roof restoration over EPDM, TPO, PVC, modified bitumen, BUR and concrete. It must be top coated with an approved finish coat, including Silicone 410, High Solids Silicone 412 or Aliphatic Urethane 510. It can also serve as a base coat beneath Aliphatic Urethane 510 in the Ure-A-Max and Max-Ply Urethane systems.

• Solids by volume: 70% ± 2%
• Elongation: 475% ± 50%
• Tensile strength: 725 ± 50 psi
• Viscosity: 6,000 ± 2,000 cps
• Weight: 8.90 ± 0.1 lbs. per gallon; flash point 80°F
• Hardness: 65 Shore A
• Permeability: 0.02 perms; water absorption 2.4%
• Dry-to-touch: 6 hours; tack-free: 8 to 12 hours; recoat: 12 to 16 hours
• Shelf life: 1 year
• Color: dark gray
• Packaging: 5 gallons and 55 gallons
• Clean up: xylene and/or acetone

Successive coats and top coats go on within 48 hours to give intercoat adhesion.

Urethane Brush-Grade 522 is the seam and flashing material of the system. It is a high-solids, single-component, moisture-cure polyurethane elastomeric coating with a thick consistency, developed from Aromatic Urethane 520 as a mastic for bridging gaps. It is used on EPDM, single-ply membranes, concrete, masonry, metal, modified bitumen and polyurethane foam, and in repairs.

• Solids by volume: 69% ± 2%
• Elongation: 350% ± 50%
• Tensile strength: 975 ± 25 psi
• Viscosity: 30,000 to 40,000 cps
• Weight: 9.2 lbs. per gallon; flash point 80°F
• Hardness: 65 Shore A
• Permeability: 0.02 perms; water absorption 2.4%
• Dry-to-touch: 6 hours; tack-free: 8 to 12 hours; recoat: 12 to 16 hours
• Service temperature range: -50°F to 200°F
• Shelf life: 18 months; 3 to 6 months under properly controlled conditions
• Color: silver
• Packaging: 5 gallon, 1 gallon and 20 oz tubes
• Clean up: xylene

It is applied by heavy brush as received, and thinning up to 6% by volume with xylene is permitted if viscosity increases. Material is stored above 65°F for cold-weather application. The product reacts with water and water vapor, and applied coatings cure in approximately 24 hours at 60°F and 40% relative humidity.

Silicone 410 is a ready-to-use, high-solids, single-component, solvent-borne, moisture-cure, fluid-applied silicone coating. It is used on vertical walls, masonry, concrete, metal, modified bitumen, single-ply roof membranes and sprayed-in-place urethane foam systems.

• Solids by volume: 69% ± 2 (ASTM D-2697)
• Initial elongation: 318% (ASTM D-412)
• Tensile strength: 500 psi (ASTM D-412)
• Viscosity: 6,000 ± 1000 cps
• Weight: 9.2 lbs. per gallon; flash point 106°F (ASTM D-93)
• Hardness: 50 ± 5 Shore A
• Reflectivity: 84% (C-1549); emissivity 0.85 (C-1371); SRI 105
• VOC: less than 250 g/L (ASTM D-3960, EPA Method 24)
• Water absorption: 2%
• Service temperature range: -40°F to 350°F
• Drying time: 1 to 4 hours; shelf life 24 months
• Colors: white, gray and tan as standard, with custom colors available
• Packaging: 5 gallon and 50 gallon; clean up with mineral spirits

The product contains combustible solvents, so it is mixed without an electric mixer. It is applied by spray, brush or roller with no thinning, polyurethane foam is coated within 24 hours of its application, and subsequent coats go on within 24 hours.

High-Solids Silicone 412 is the alternative top coat. It is a single-component, moisture-cure silicone with 92% ± 2% solids by volume, 250% ± 25% elongation and 330 psi ± 50 psi tensile strength. Initial reflectivity is 0.87 (C-1549) and initial emissivity is 0.89 (C-1371). VOC is less than 50 g/L, service temperature range is -40°F to 350°F, and standard colors are white, gray and tan.

The polyester fabric is a 100% polyester textile of hydraulically entangled staple fibers. It has 100% elongation, 35 psi tensile strength, a weight of 11 lbs per square, 22 mils of bulk, and is made in widths of 36, 20, 12, 6, 4 and 2 inches. It is installed by laying the fabric into a wet layer of base coat and applying another layer of coating over its top side.

EcoCleaner 925 is diluted 5:1, applied at 1 gallon per 150 sq. ft. and followed by power washing at a minimum of 3,000 psi. Pressure washing at 3000 to 4000 psi is the range given for the system. The pre-inspection covers HVAC flashing, drainage, drains, seams, terminations, reglets, penetrations, water leakage, sign or display anchorage, parapet detail, wet or damp insulation, and coping and flashing.

Long-term StarGard warranty plans with no dollar limit are offered for eligible systems, and each job is approved by American WeatherStar before it begins.