Roof Coating vs. Replacement Content
One question decides this, and it is answered by survey rather than by opinion. Below is what makes a roof a candidate and what rules it out.
When Coating Works
The deck is sound. The assembly is dry. Existing damage is limited and repairable. Drainage functions. The surface will accept a compatible product with acceptable adhesion.
Under those conditions, coating or restoration is genuinely good value. You extend the assembly's service life at a fraction of replacement cost, and on a foam roof it's simply required maintenance.
When It Doesn't
Moisture trapped in the assembly. Damaged decking. Drainage that doesn't work and isn't being corrected. Deterioration extending through the system rather than sitting on its surface. A substrate that won't hold a coating reliably.
In those situations a coating conceals the problem. The moisture keeps working on insulation and deck while the roof looks renewed from above, and the eventual repair is larger and more expensive than it would have been.
How Candidacy Gets Determined
Moisture survey, whether by infrared, capacitance meter, or core samples, is the most important test and the one most often skipped. Adhesion testing on a small area. Assessment of existing damage. Drainage evaluation. Identification of any previous coating and its compatibility.
A coating proposal made without any moisture assessment is a proposal made without the key input.
The Economics
A coating on a genuine candidate typically extends service life meaningfully for a fraction of replacement cost, and it can often be repeated.
A coating on a roof that needed replacement buys a short deferral, and you then pay for replacement anyway plus the coating. That's the scenario worth avoiding, and it's common enough to be worth asking about directly.
What a Vague Answer Means
If a contractor can't say how they established the assembly is dry, assume they didn't check. A coating applied over trapped moisture looks identical to a good one for the first year or two, which is precisely why the question has to be asked before the work rather than after.
The Question to Ask
Ask any contractor proposing a coating: how did you determine the assembly is dry?
A specific answer referencing a survey method is what you want. A general assurance that it looked fine is not.
Frequently Asked Questions:
How long does a roof coating last?
Service life depends on the product, application thickness, surface preparation, sun exposure, foot traffic, and drainage. Coatings are a wear layer and are intended to be renewed periodically rather than being permanent. On a well-prepared candidate roof, a coating can often be reapplied when it wears, extending the assembly repeatedly.
Can a coating be applied over a wet roof?
No. Coating over trapped moisture seals it into the assembly, where it continues damaging insulation and decking while the surface looks renewed. Wet areas must be identified and removed before any coating is applied. This is why a moisture survey is the most important step in evaluating a roof for coating.
How do I know if my roof is a coating candidate?
Through a moisture survey, adhesion testing, assessment of existing damage, and evaluation of drainage and any previous coating. Visual inspection alone can't determine whether moisture is present in the assembly. Ask any contractor proposing a coating how they established the roof is dry.
Is coating a permanent alternative to replacement?
It extends service life rather than replacing the assembly, and on suitable roofs it can be renewed repeatedly over many years. Eventually the underlying system reaches a point where coating is no longer viable. On a foam roof, periodic recoating is how the system is designed to be maintained rather than an alternative to anything.
See what we can document, or send us the letter. Or call (480) 565-7663.
