PVC and EPDM Silicone

PVC and EPDM Silicone is a Kool Coats coating system that finishes a prepared PVC or EPDM roof with KoolFlex silicone. It is listed for the USA market under the PVC and EPDM family, and its coating chemistry is silicone. The finish is KF-600 KoolFlex high solids silicone, with membrane-specific primers and a KF-460 mastic for detail work.

The system is used on roofs where standing water and long sun exposure drive the choice of coating. It is one of the silicone roof coating systems offered for single-ply restoration.

PVC and EPDM are prepared with their own cleaner and primer schedules. Compatible repairs are completed, and the KF-600 silicone is applied to the required build.

• P-313 EPDM Bleed-Block Primer: an EPDM primer for acrylic or silicone coatings that reduces discoloration through the finish
• RP-105 Rinseable EPDM Cleaner: a cleaner made for EPDM
• P-301 Multipurpose Primer: a primer that bonds to PVC
• KF-460 KoolFlex Mastic: the silicone mastic for repairs and details
• KF-600 KoolFlex high solids silicone: the roof coating

KF-600 is a single-component, moisture-cure, elastomeric silicone roof coating with 95% volume solids. Its primary intended use is on low-slope roofs, and it is ASTM D6694 compliant. It comes in three standard colors: White, Tan and Gray.

The coating is listed for masonry, concrete, metal, vertical walls, sprayed-on urethane foam, smooth and granulated BUR, modified bitumen, and single-ply membranes including TPO, PVC, Hypalon and EPDM.

• Rain-safe in 1 hour
• Initial elongation: 279% at 73 degrees F and 248% at 0 degrees F
• Tear strength, Die C: 30 lbf/in
• Ponding water resistance: low permeance, 6.3 US perms at 73.4 degrees F and 50% relative humidity
• Initial SRI value: 109

The low permeance and the 30 lbf/in tear strength are the listed properties behind its use in standing water.

KF-460 is a high solids, moisture-cure, 100% silicone mastic. It seals and repairs roofs, flashings, walls, masonry and metal roof seams and fasteners, and it goes on by trowel or brush on vertical or horizontal surfaces. A single application builds up to 1/4 in.

Listed adhesion covers concrete, masonry, vinyl, fiber cement, polyurethane foam, EPDM, aged acrylic coatings, granular cap sheet, wood, metals and Kynar. A primer may be needed on some of them. The mastic may be applied to wet and underwater surfaces.

• Layer thickness for cracks, breaks, tears and holes: 1/8 to 1/4 in, spread 2 to 4 in beyond the damage
• Tack free in 1 to 3 hours, fully cured in 24 hours
• Hardness: 70 Shore A
• Tear resistance: 82 lbs/in

P-301 is a hybrid, high-solids multipurpose roof primer. It bonds to TPO, PVC and metal, and it is used under silicone or acrylic systems. It is not for use with EPDM.

The solids content is 51.4% by volume and 51.12% by weight, nominal. Weight is 8.36 lbs per gallon, VOC is 22 g/l, and the color is light gray. It blocks asphalt oils from bleeding through silicone systems. Dry to touch takes about 1 hour and the film is topcoat ready after 2 to 4 hours.

The cured silicone thickness is set for the chosen assembly, with primer and detail treatment allowed for separately. The KF-600 data lists a recommended rate of 1.5 gallons per 100 sq ft for most substrates and a dry coat thickness of 20 mils. KF-460 mastic has an application rate of 12 sq ft at 1/8 in and 24 sq ft at 1/16 in.

KF-600 is applied by standard airless spray or medium-nap roller, with a brush for touch-up. Because the material is viscous, the airless sprayer needs at least 3500 psi at the gun head and a pump output of at least 3 gallons per minute. Hoses are BUNA-N jacketed with a minimum inside diameter of 3/4 in, and the reverse-a-clean tip has a minimum orifice of .030 with a 50 degree fan.

The coating is not thinned. Application is avoided below 40 degrees F and when rain is expected within four hours. The coating can dry in 1 to 4 hours.

Surfaces for KF-460 are cleaned by power washing and wire brushing. EPDM roofs may need aggressive washing and a second cleaning.

Full System Limited Warranties for the KF-600 coating range from 5 to 20 years. The KF-460 mastic sheet carries the Kool Coats 10-20 year Material Warranty, with a Labor and Material option for a fee. Inspections are at least twice a year and after severe weather.

KF-600 is a single-component, moisture-curing silicone rubber roof coating with 95% solids, applied as a one-pass, high-build coat. It comes in 1 gallon, 5 gallon and 50 gallon sizes. Temperature stability runs from -67 to 350 degrees F. The spray equipment listed is a 3,500 psi minimum, a 3 gpm pump, a 3/4 in hose and a .030 tip with a 50 degree fan.