Silicone and acrylic roof coatings in Vancouver, WA

A roof coating is a liquid membrane rolled or sprayed over an existing roof. It cures into a continuous rubbery layer that covers seams, fasteners and small cracks, and it adds a fresh weathering surface over worn material. Coatings are used mostly on low-slope roofs, such as commercial membranes, modified bitumen and older built-up roofs, and on metal roofs on shops, barns and commercial buildings.

A coating is not a cure for a failing roof. It only works when the roof underneath is sound, dry and well attached. Coating over wet insulation or rotted decking traps the moisture and hides the damage until it gets worse. That is why every coating job we take starts with a moisture check, and why we sometimes tell owners that a coating is the wrong choice for their roof.

Coating types and where each fits

Silicone is the coating we use most often around here. It stands up to ponding water without breaking down, which matters on low-slope roofs that hold a little water for days during the wet season. It also stays flexible in cold weather and resists UV. Its downside is that dirt sticks to it, and most other materials will not bond to silicone later, so future repairs have to be made with more silicone.

Acrylic coatings are water-based, cost less and come in bright white that reflects summer sun. They work well on metal roofs and on low-slope roofs with good drainage, but standing water softens them over time. Polyurethane and other specialty coatings are tougher and suit roofs with foot traffic or rooftop equipment, though they cost more. We match the coating to how the roof drains and how it is used, not just the price.

What a coating job includes

The coating is only as good as the prep under it. We clean the roof with a power washer, remove loose material, and repair problem spots before coating. On metal roofs, that means treating rust and sealing every fastener. On membrane roofs, it means reinforcing seams with fabric and coating, then rolling the full surface to the thickness the product calls for, measured with a gauge as we go. Thin spots get a second pass.

• Moisture check and core samples
• Power washing and surface cleaning
• Seam and fastener reinforcement with fabric
• Rust treatment and primer on metal roofs
• Base and top coats to full thickness
• Clear drains and scuppers after cleanup

When a coating is the wrong answer

If moisture readings show wet insulation or soft decking across a large part of the roof, a coating will not fix it. Water trapped under a coating keeps rotting the deck and can blister the new layer from below. The same goes for a roof with large sections of membrane pulling away from the deck, or a metal roof with widespread rust holes. Those roofs need sections replaced or a full new system, and we will tell you so plainly.

Coatings also are not a fit for steep-slope shingle roofs. Coating asphalt shingles can trap moisture, void manufacturer warranty terms and make the roof harder to repair later. If a seller offers to coat your shingle roof to extend its life, it is worth getting a second look. For shingles, moss treatment, spot repairs and eventually replacement are the right tools. We are happy to look at a shingle roof and explain the real options.

Weather windows for coating

Coatings need dry weather to cure. Most products need the roof to stay dry for a set number of hours after application, and some need temperatures above a minimum. In Vancouver that means most coating work happens from late spring through early fall. We watch the forecast closely, and we will move a start date rather than risk rain on fresh coating. Planning a coating project in winter so it is ready to go by May is a good approach.