Elastomeric Roof Coating Cost: $0.50 to $3.00 per Sq Ft

Roof coating cost per square foot

National figures. Where two guides price the same coating, both are shown.

Angi's whole-job figure is the useful one for a house: $543 to $2,528, with most homeowners paying about $1,475. The per-square-foot price moves with the coating, the number of coats, and how much cleaning and repair the roof needs before anything goes on.

Do this now: a leak on a roof you plan to coat

Fix the leak first: Angi says a coating will not stop a leak that is already coming through, so the cause has to be repaired before any of the $0.50 to $4.50 per square foot of coating goes on.

1. Fire, smoke or sparks: get everyone out and call 911. Water near wiring or fixtures: turn off power to that area at the breaker only if you can reach it from a dry spot.
2. Catch the water and move what you can out from under it.
3. Stay off the roof. OSHA warns that roof surfaces can be steep and slippery and says a damp roof should dry before anyone walks on it. Put up a tarp only from the ground, or have a roofer do it; never climb onto a wet or icy roof.
4. Call the roof line and say the roof leaks now; ask for the repair first and the coating quote second.

Is it urgent? Coating can wait, a leak cannot

A coating is planned maintenance that can wait for dry, warm weather, since acrylic needs temperatures above 50°F to cure; water coming inside is urgent, and Angi says emergency roof service adds $100 to $300 or more. If water is in the attic or the rooms below, see emergency roof repair; if the roof only looks worn, book the coating for spring or fall.

Silicone roof coating vs acrylic

• Silicone roof coating. $1.50 to $4.50 per square foot installed in HomeGuide's figures, lasting 10 to 15 years. HomeGuide says silicone resists ponding water better than acrylic.
• Acrylic (elastomeric). The cheaper option at $0.50 to $3.00 installed (HomeGuide) or $0.65 to $1.75 (Angi), with a reseal about every 10 years per Angi. It needs temperatures above 50°F to cure and does poorly on flat roofs with ponding.
• Polyurethane. $1.50 to $4.00 installed (HomeGuide) or $2 to $5 (Angi). It also handles ponding better than acrylic.

Ponding means water still standing more than 48 hours after rain, by the National Roofing Contractors Association's definition. If your roof does that, fix the drainage first or choose a coating rated for it; the flat roof repair guide covers drains and low spots.

When a roof coating will not work

• An active leak. Angi says a coating will "not stop" a leak that is already coming through. Fix the cause first; see roof leak repair.
• Asphalt shingles. Angi says coating an entire shingle roof "is not recommended because it can impact drainage," and HomeGuide reports that the NRCA advises against it. A worn shingle roof needs repair or replacement; see the roof replacement cost guide.
• Wood shingles and shakes. HomeGuide says not to coat them. See cedar shake roof repair.
• A dirty or failing surface. Coatings will not bond to a dirty roof, and both guides limit coating to roofs with a sound surface.
• Cold weather, for acrylic. It needs temperatures above 50°F to cure.

Where coating fits: flat, metal and foam roofs

Angi and HomeGuide agree on where coatings work: low-slope and flat roofs with a sound surface, including metal, spray foam, built-up and modified bitumen. On a metal roof, an elastomeric coating can seal worn seams and fastener heads across the whole roof at $0.50 to $4.00 per square foot (HomeGuide), once any active leaks are fixed. On a flat roof that is sound but aging, a coating can add years before replacement.

Foam roof recoat schedule

Spray foam must stay coated. HomeGuide says foam needs an elastomeric or silicone topcoat for UV protection, and Fixr notes that sun breaks down exposed foam. Rosie on the House, the Arizona home-improvement radio show, estimates that about 90 percent of Arizona's flat roofs are spray foam, so this schedule matters there more than anywhere; the Phoenix service page covers local work. Sources disagree on timing:

Recoat intervals vary from 5 to 15 years across sources. Ask the roofer what your coating's maker specifies.

Recoat prices on foam: silicone $1.50 to $4.50 and polyurea $1.50 to $4.00 per square foot (HomeGuide); Angi lists silicone topcoat material at $1.40 to $2.50 and acrylic at $0.15 to $0.75 per square foot. Fixr says damaged foam can be patched and recoated locally, so a small blister does not mean recoating the whole roof.

Roof coating contractors: questions to ask before you pay

• Will you find and fix the leaks and wet areas before coating?
• How will you clean and prepare the surface?
• Which coating, how many coats, and is it suited to water that ponds on my roof?
• What is the written warranty, and when will it need a recoat?

Walk away from a company that offers to coat an asphalt shingle roof or to coat over a leak instead of repairing it. If solar panels sit on the roof, ask how the company will coat around or under the racks; the solar on a flat roof page covers the tradeoffs.