Acrylic Roof Restoration Coating System Tile Roof

The Acrylic Roof Restoration Coating System Tile Roof is a Metacrylics system for coating an existing tile roof. It belongs to the Metacrylics family of commercial roof coating systems and is published as sheet A-09, titled Tile Roof Restoration Coating System, dated 09-25-17.

The system is water-based and acrylic throughout. It is one of the tile roof assemblies in the Metacrylics range, alongside separate systems for metal, EPDM, TPO, concrete, foam, built-up and torch-down roofs. Metacrylics is based at 365 Obata Court, Gilroy, California.

The assembly is built up over the existing tile roof in four stages, from the tile surface upward.

• Acrylic Roof and Tile Primer, applied to the existing tile.
• Acrylic Clear Sealer.
• First Tile Sealer color coat.
• Second Tile Sealer color coat.

A note on the sheet requires all rooftop penetrations, drains, scuppers, flashings, skylights and perimeter edge metal to be sealed and reinforced by 3-coursing with Metacrylics Acrylic Gel and polyester fabric.

Metacrylics Roof and Tile Primer is a clear, water-based acrylic primer with penetrating characteristics. It is white as a liquid and dries clear and not tacky. It is applied to improve adhesion of elastomeric coatings to existing roof or walking surfaces. It is commonly applied over wood, asphalt-based surfaces, concrete, stone, slate, metal, tiles, fiberglass, stucco and acrylic coated surfaces, and it binds fine surface dust on composite substrates.

• Solids: 16-20.
• pH: 7-8.
• Viscosity at 23 degrees C (Brookfield RV, spindle 5, 50 rpm): 1500-6000 cps.
• Density at 23 degrees C: 1.03 g/cm.
• Dispersion type: anionic. Freeze/thaw stability: not resistant.
• Film: white, not tacky, elongation at break 700 percent, glass transition temperature 17 degrees C, water absorption 5 percent.

The primer contains no zinc oxide, which independent testing by ICC-ES and UL Laboratories confirmed. Spray or roller application is at 0.25 to 1 gallon per 100 sq. ft., with a .031 spray tip for spray work, and drying takes 1 to 4 hours. Thinning with water is permitted if necessary. Concrete must be fully cured for 30 to 60 days, and new glazed asphalt and torch-down single-ply assemblies must wait 6 months or more before coating.

Metacrylics Acrylic Roof and Tile Sealer is a water-based coating that combines the gloss, clarity and weathering of acrylics with the toughness of epoxies. It is an all-acrylic latex dispersion that can serve as a seal or topcoat on indoor and outdoor roof and tile surfaces, including other acrylic coatings, natural stone, terrazzo, metal, concrete, slate, clay and tile roofing. It is available clear or in 36 colors. The clear sealer exceeds the coefficient of friction standard ASTM D-2047 and complies with VOC anti-smog ordinances.

• Appearance: white stable emulsion that dries clear.
• pH 7.9 (plus or minus 0.2); specific gravity 1.03; 8.3 lbs per gallon.
• VOC content: less than 3 percent.
• Refractometer solids: 22.5 percent (plus or minus 0.2 percent).
• Flash point: none (C.O.C. method).
• Gloss: 90 (ASTM D-523, 60 degrees).
• Leveling: excellent (ASTM D-2801). Re-coatability: excellent (ASTM D-3153-78).
• Packages: 1 gallon, 5 gallon and 55 gallon drum.

The sealer is applied by spray or roll and is also supplied in a 275-gallon tote. The tile system itself runs in two steps on the manufacturer's product page, Roof and Tile Primer followed by Roof and Tile Sealer, and the primer penetrates porous tile. The sealer is for approved tile roofs, decks and walkways, and the manufacturer's tile page gives its colors as clear plus more than 30. Walking-deck areas take Extreme Weather as the topcoat rather than the sealer.

Two applications are used. The first coat is a penetrating sealer at 1/4 gallon per 100 sq. ft. and the second is a protective barrier against UV, water, dirt, fungus, mildew and staining at 1/8 gallon per 100 sq. ft. The sealer can also serve as a stain-blocking primer. Surfaces are cleaned and rinsed, with TSP used to remove dirt and oils, and old roofs are pressure washed first. Non-Metacrylics surfaces are tested in an inconspicuous area.

At 68 degrees F and 50 percent relative humidity the sealer sets to touch in 30 minutes, can be re-coated in 1 to 2 hours, takes light traffic in 4 to 8 hours and vehicle or heavy traffic 12 to 24 hours after the final coat. It is not applied if rain or moisture is forecast within 24 hours. Application is by pump-up high-volume low-pressure sprayer, lambswool pad, paint roller or airless sprayer. Wet maintenance is avoided for 48 hours after the first application; afterward the surface is maintained by sweeping and periodic TSP use. Shelf life is 2 years from the manufacture date.

Acrylic Gel is the water-based acrylic elastomeric mastic used for flashing and fabric reinforcement at the details of this system. It is available in white, gray and clear and contains no zinc oxide.

• Cool Roof Rating Council: solar reflectance 0.87 and thermal emittance 0.90 (C-1371), seller ID 0660. Title 24 compliant.
• ICC-ES Report No. 4785.
• Fire rating Class A and wind uplift 105 PSF.
• Low temperature flexibility: pass at 1 inch and -40 degrees F (ASTM C836).
• Tensile strength 156 psi and elongation 149 percent average at 81 mils including 10 mil stitchbonded polyester fabric.
• Hardness: Shore A 41. Peel adhesion on concrete: 6.3 lbs per linear inch.
• Weathering: 2,000 hours weatherometer with no cracking, crazing or erosion and slight chalking.

Applied by 3-coursing, a smooth layer of gel goes over the area, fabric is pressed into it, and a second layer of gel covers the fabric, with the field area overlapped at least 2 inches and 2 inches up the penetration, curb or wall. Drying takes 12 to 24 hours.

Metacrylics Extreme Performance Acrylic White is the white reflective elastomeric coating in the Metacrylics range. It carries about 50 percent more TiO2 and 50 percent more copolymer resin than the standard acrylic white. Initial elongation is 592.63 percent (ASTM D6083-05e1) and 521.12 percent at break (ASTM D412, Die C). Its Cool Roof Rating Council figures are solar reflectance 0.90, thermal emittance 0.88 and SRI 114. It weighs 11.3 lbs per gallon with a VOC content of 27.5 grams per liter.

Spray application is two coats at 1.5 gallons per 100 sq. ft. each, 3 gallons in total, with a .035 to .039 spray tip and 12 to 24 hours between coats. A rolled application uses between 2 and 3 coats, each 1.33 to 1.5 gallons per 100 sq. ft. Wet acrylic is extremely slippery underfoot.