Proposal Review Guide
A roof coating proposal is one of the most oversold documents that crosses an owner's desk. Done on the right roof, with the right system, at the right time, a restoration coating can extend service life meaningfully and defer a capital re-roof for a fraction of replacement cost. Done on the wrong roof, it is a coat of paint over a failing assembly that buys eighteen months and complicates the eventual tear-off. The proposal in front of you rarely makes that distinction for you, because the contractor's incentive is to sell the coating. This guide gives owners and asset managers a structured way to interrogate a coating proposal before signing, separating genuine restoration from cosmetic deferral.
First Question: Is This Roof a Candidate at All
Coatings restore roofs that are weathered but sound. They do not fix roofs that are wet. The single most important determination, and the one most proposals skip, is whether the existing assembly has trapped moisture. Coating over saturated insulation seals water inside the system, where it continues to degrade the deck and the membrane while looking fine from above. A credible proposal is preceded by a moisture survey, typically infrared, nuclear, or capacitance testing, with the wet areas mapped and a plan to remove and replace them before any coating is applied. If the proposal does not reference moisture testing, that is the first thing to demand.
Candidacy also depends on the substrate. Coatings behave differently over different systems. A weathered but intact EPDM, TPO, or PVC membrane, an aged modified bitumen or BUR surface, a metal roof with sound seams, or an existing SPF roof are each viable candidates under the correct coating chemistry. A membrane with widespread seam failure, brittle and cracking field membrane, or compromised flashings is not a coating candidate, because a coating cannot restore adhesion or bridge structural seam failures. Ask the proposer to state explicitly why this roof is a restoration candidate rather than a re-roof candidate, and weigh that against your own condition data.
Read the Coating Chemistry, Not Just the Price
"Roof coating" spans several chemistries with very different properties, and the proposal should name which one and justify it. The common families each have trade-offs that matter for your roof's exposure and substrate:
- Acrylic coatings are economical and reflective but generally not suited to ponding water, which makes them a poor choice for roofs with known drainage problems.
- Silicone coatings handle ponding well and weather slowly, but they attract dirt that reduces reflectivity over time and complicate future recoating because little adheres to cured silicone except more silicone.
- Polyurethane coatings offer impact and traffic resistance, useful on roofs with frequent foot traffic or rooftop equipment access.
- SPF-applied coatings are paired with spray foam systems and follow different specification and maintenance logic entirely.
A proposal that does not name the chemistry, the manufacturer, and the reason it suits your substrate and drainage is not specifying a system; it is quoting a commodity. Mismatched chemistry, such as acrylic on a ponding roof, is a predictable early failure that the owner pays for twice.
Scrutinize the Specification Details
The difference between a coating that lasts and one that fails is almost always in the details the cheap proposal omits. A defensible specification states the surface preparation, the application rate, and the reinforcement of vulnerable areas, because a coating's performance is governed by how much material goes down and how well the substrate was cleaned first.
When reviewing the spec, confirm it addresses each of the following in writing:
- Surface preparation: cleaning method, removal of loose material and contaminants, and any required priming for the specific substrate.
- Dry film thickness or coverage rate stated in gallons per square or mils, not left vague. Underapplication is the most common way contractors protect margin at the roof's expense, and it is invisible once the coating cures.
- Detail work: reinforcement of seams, penetrations, drains, and flashings with embedded fabric or detail-grade material before the field coat.
- Repair scope before coating: the moisture-damaged areas to be removed and replaced, and any membrane repairs to be completed first.
- Number of coats and cure conditions, including temperature and weather constraints for application.
Interrogate the Warranty Carefully
Coating warranties are where proposals most often mislead, because a long warranty term is presented as proof of quality when its actual coverage may be narrow. Read what the warranty covers, not just its length. A material-only warranty obligates the manufacturer to replace the coating material if it fails but covers none of the labor to reapply it, which is the majority of the cost. A labor-and-material or system warranty is worth far more. Confirm who stands behind it, the manufacturer or the contractor, and whether the manufacturer inspected and approved the application, because contractor-only warranties evaporate when the contractor does.
There is a second, frequently overlooked warranty consequence. If the existing roof is still under a manufacturer membrane warranty, applying a coating can void it. Many membrane manufacturers will not honor coverage on a roof that has been coated with a third-party product. Before accepting a coating proposal on a roof with remaining membrane warranty, weigh the value of the coverage you would surrender against the life extension the coating offers. A proposer focused on the sale will not raise this; the owner has to.
Compare It Honestly Against Replacement
The final test is economic and depends on time horizon. A coating's value is the cost of restoration divided by the years of service life it credibly adds, compared against the annualized cost of replacement. On a roof with five or more years of sound life remaining over a dry assembly, a quality coating can be the clearly superior capital decision. On a roof near the end of its life with trapped moisture and failing seams, coating is deferral that increases the eventual tear-off cost and risk. Insist that the proposal state the expected added service life in years and the assumptions behind it, then test that claim against your own condition data and capital timeline. A coating bought to defer a re-roof you will face in two years anyway is rarely worth what it costs. A coating that genuinely buys a decade on a sound roof is among the better dollars an owner can spend on a building envelope.