Coating can extend service from a suitable roof. It cannot make wet insulation or rotten decking sound. Establish the retained assembly and necessary repairs before comparing restoration with replacement.
The coating sample looked excellent. Under it, the roof's condition remained a question. Dave set the sample down while Pat opened the inspection photographs. "Let's price what we're keeping before we pick how shiny it gets."
A mostly dry, stable roof with repairable details is a different candidate from one with widespread wet layers or major drainage defects. Both can look much the same from an upstairs window after a fresh coat.
Begin Beneath the Surface
An inspection should identify the existing membrane, previous repairs and coatings, attachment condition and possible moisture. A dry-looking roof on a sunny afternoon does not establish that the insulation underneath is dry.
GAF's liquid-applied roofing manual requires suitable substrates and addresses moisture surveys, removal of wet insulation and compatibility checks. Its specific warranty criteria belong to its systems; they should not be treated as universal thresholds for every coating product.
Ask for the findings in a form you can use: a roof plan with investigated areas, photographs and the repair scope. If moisture is discovered, the proposal should explain its extent and the basis for removal rather than assuming a small patch around the visible leak is sufficient.
The Coating Should Not Be Asked to Find the Leak
Open seams and failed flashings need appropriate repair before coating. So do damaged areas that will not provide a suitable base. Cleaning, drying, compatible preparation and reinforcement at specified details are part of the work that makes restoration useful.
We read the preparation line twice. Plenty about litres and area, almost nothing about the open details in the photographs. Dave moved those repairs onto the comparison sheet. A useful restoration scope names the defects it corrects and the conditions it retains; the coating quantity cannot answer either question for you.
Persistent water deserves its own answer. A product's permitted exposure varies, but even a coating suitable for a particular wet condition cannot remove water weight or clear the drain. A shinier puddle is still a puddle.
A Coating Decision Has Prerequisites
A favourable surface appearance is only the beginning of the assessment.
Identify the roof
Confirm membrane, previous coatings and assembly.
Check dryness and soundness
Investigate moisture and repair unsuitable areas.
Confirm compatibility
Use the selected coating's required preparation and adhesion checks.
Compare the scope
Weigh restoration, drainage corrections and replacement with clear inclusions.
What the two prices actually include
A restoration price and a replacement price often include different work. Replacement may include removing wet materials, improving slope, rebuilding curbs and changing insulation. Restoration may retain those existing conditions.
Then the owner mentioned a future terrace or equipment installation. We put that into both proposals before comparing them. Extensive alteration soon after coating could make the sequence poor value even if the roof was a suitable restoration candidate today. The useful comparison had to include what was coming next, not just what the two surfaces would look like next week.
Do not accept a guaranteed service-life extension based only on age or a photograph. Condition, preparation, exposure and maintenance all matter. Ask what the written warranty covers and whether labour, leak investigation or only material defects are included.
Pay for the Problem You Need Solved
Consider two roofs. One has a sound, dry assembly and a handful of repairable details; restoration may preserve useful material and avoid unnecessary removal. The other needs widespread wet insulation removed, drainage changed and curbs rebuilt. Replacement or more extensive reconstruction may address those needs more directly.
The wet-insulation survey guide explains how evidence supports that distinction. A coating quote is attractive when its retained assembly is worth retaining. It is less attractive when it postpones the same removal work for a short-lived improvement in appearance.