Someone Coated This Roof Three Years Ago and It’s Peeling: Can a Failed Silicone Job Be Saved?

When a silicone roof coating is peeling, sheeting off in the wind, or lifting along the seams three years after it went down, the product almost never failed — the preparation did. Silicone is a proven 20-year restoration chemistry, but it has to bond to something clean. Oil, residual solvent, dust, loose granules and an incompatible old coating underneath are the causes that show up again and again in manufacturer failure analyses. That distinction matters to you financially, because a coating that failed on prep can very often be rescued: silicone bonds to cured silicone without a primer, so a roof that passes an adhesion test can usually be washed and topcoated for roughly $1–2 per square foot rather than stripped and redone at $3–6, or torn off at $10–16. Here is how a competent contractor decides which one you are looking at.

First: is it peeling, or is it just ugly?

These get confused on the phone constantly, and they have completely different price tags.

• Delamination — the coating separates from the membrane below and comes away in sheets or strips, often large enough to grab by hand. The underside is usually clean and glossy, which is the tell: the silicone never bonded at all. This is an adhesion failure.
• Cohesive failure — the coating tears within itself, leaving silicone on the roof on both sides of the break. Rarer, and usually a mil-thickness problem.
• Surface defects — pinholes, fish eyes, craters, dirt pickup, chalking. Cosmetic, cheap to correct, and not a reason to redo a roof.

Only the first one is a true failure. If a contractor tells you a roof with pinholes needs a full tear-off, get a second opinion.

The adhesion test that decides the whole job

You cannot tell by looking whether the remaining coating is sound. The industry answer is a field adhesion test, and it is the single most important thing to insist on before anyone quotes you a rescue.

The procedure is standardized and cheap. The contractor brush-applies a patch of the proposed coating over a small area, embeds a strip of polyester reinforcing fabric into it while wet — commonly a 2″ × 6″ strip, though manufacturers like Gaco and Polyglass publish their own dimensions — and leaves roughly two inches uncoated as a pull tab. That patch cures for a minimum of 24 hours, then someone pulls the tab back at as near a 180-degree angle as possible and reads the force required, along with what the failure looks like. The formal version of this is ASTM D903 peel adhesion, which sits inside the ASTM D6694 umbrella that governs silicone roof coatings.

Two things make this test meaningful rather than theatrical:

• Multiple patches, in the worst places. One patch in the middle of a clean field tells you nothing. Patches belong in ponding areas, near HVAC units where oil mist lands, at seams, and on each distinct-looking section of the old coating.
• The right prep in the patch. Solvent choice genuinely changes the result — wipe testing on galvanized metal has shown xylene or acetone restoring adhesion where isopropyl alcohol produced almost none. A patch prepped differently than the real job would be prepped is not a valid test.

What a rescue actually costs, and when it isn’t one

If the patches hold, the repair is straightforward and the savings are real: pressure wash the roof, mechanically abrade or condition any glazed areas, cut out and re-detail the delaminated sections with silicone mastic and reinforcing fabric, then apply a full topcoat to restore total mil thickness to warranty spec. That is a one-to-three day job on most buildings and lands in the $1–2 per square foot range — a fraction of the original restoration, and an order of magnitude under replacement. The same logic that makes coating beat tear-off in the first place, explained on our no tear-off roofing page, applies twice over here.

If the patches pull off clean, be skeptical of anyone who still wants to coat over it. The honest answer in that case is removal of the failed material — which is real labor and should appear as its own line item on the quote, never buried in a square-foot price. And there is a third case that has nothing to do with the coating at all: if a moisture survey finds wet insulation under the membrane, no topcoat fixes that, and roughly a quarter of the roof holding moisture is where the conversation turns to replacement. Our breakdown of what silicone roof coating costs per square foot covers how each of those scopes gets priced.

Who holds the warranty after a rescue

This is the part building owners get wrong, and it is worth being blunt about. When a second contractor coats over a first contractor’s work, the original warranty is gone — and the new manufacturer warranty is not automatic either. Coating manufacturers inspect before they issue one, take core cuts, and will refuse to warrant a system until the contractor brings it to spec. They also require the applicator to be certified on their system, which is exactly why who applies your coating determines whether the warranty is worth anything.

Expect the warranty fee itself to be a line item, roughly $0.06–0.10 per square foot for a 10-year term and $0.17–0.30 for a 20-year term. Pay it. A rescue coat without a manufacturer warranty behind it is just the last contractor’s mistake with a fresh coat of white on top. Getting the system back to a genuine 20-year term is the entire point — see how long a properly applied silicone roof coating actually lasts. If your existing coating is acrylic rather than silicone, the compatibility questions are different and we cover them separately in recoating an acrylic roof with silicone.

Get a second opinion before you pay for the same roof twice

If a coating you already paid for is failing, you are owed a real diagnosis before you are sold anything else. NoTearOff Roofing will walk the roof, set adhesion test patches, check for trapped moisture, and tell you plainly whether your existing coating can be saved — including when the answer is that it can’t. We restore commercial flat and low-slope roofs across Pennsylvania, New Jersey, Delaware, Maryland, Ohio and West Virginia; owners in our home market can start with our Pennsylvania silicone roof coating page.

Request a free commercial roof assessment and ask specifically for the adhesion test. It is the difference between a $1–2 per square foot fix and a $10–16 per square foot tear-off, and it takes 24 hours to find out which one you need.