Coating Or Cover-Up? How To Tell Which One You Are Being Sold

The difference in one sentence

A coating system starts with finding out what is wrong under the existing roof and fixing it. A cover-up starts with the sprayer.

The questions

"How did you check for moisture under the existing membrane?"
The answer should name a method - infrared scan, moisture meter, core samples - and should come with results: which areas were wet and what is being done about them. "It looked dry" is not a method. A coating over wet insulation seals the moisture in and hides the deterioration until the deck fails.

"What repairs happen before the coating goes on?"
Open seams, failed flashings, loose edges, cracked pitch pockets, damaged drain seals - each one should be listed as a repair, priced as a repair and done before any coating. If the proposal's answer to every defect is "the coating will take care of that", it is a cover-up.

"What is the specified dry film thickness, and how will it be verified?"
Coatings are sold by thickness. The manufacturer's warranty depends on the applicator hitting a number of mils, measured, and usually documented. A proposal without a thickness is a proposal for an unknown amount of product.

"What reinforcement goes at the details?"
Seams, penetrations, transitions and edges get fabric or mastic reinforcement before the field coat. A coating alone across a moving seam will crack at the seam.

"Whose warranty is it, and what does it cover?"
A manufacturer's system warranty means the manufacturer inspected or approved the installation. A contractor's warranty means the contractor stands behind the work. Read what is excluded - ponding water and pre-existing conditions are common exclusions, and on a roof that ponds, that matters.

"Is coating even the right answer for this roof?"
Sometimes the honest answer is no. A roof with widespread wet insulation, failed decking or a membrane that has reached the end is a replacement, and a coating is money spent on postponing that decision by a couple of years. A contractor who sells coatings and also says "not this one" is worth listening to.

What good looks like

A written scope with a moisture survey result, a repair list, a named product, a specified thickness, detail reinforcement, and a warranty you have read. That is a coating system, and it can add many years to the right roof. Anything shorter is a cover-up with a nice colour.

← All articles