Rejuvenation vs. Coating vs. Sealant

If you have an aging roof, sooner or later someone offers to spray something on it. The word they use might be coating, sealant, or rejuvenation. Those are three different products that do three different jobs, and the people selling them do not always keep them straight.

Here is the difference, from a company that sells only one of the three.

What does a roof coating do?

A coating is a new layer. It goes on as a liquid, usually acrylic or silicone, and cures into a continuous film over the top of the roof. It does not change the material underneath. It covers it.

Coatings are a real product with a real job. On a flat or low-slope commercial roof, a coating is often the standard answer, and a good one. If that is the roof you have, talk to a commercial roofer about it.

On a steep-slope asphalt shingle roof, it is a different conversation. A shingle roof is built from overlapping pieces that shed water downhill, and a film painted across it behaves differently from a film on a flat membrane. A coating also changes how the roof looks, often to a lighter color. When one fails, it tends to peel or flake, and a peeling coating on a shingle roof is a mess to deal with.

What does a roof sealant do?

A sealant fixes a point. It is roofing cement or caulk, applied to a specific spot: around flashing, over exposed nail heads, along a crack, at a pipe boot.

That is useful work and every roof needs some of it eventually. But a sealant does nothing for the shingles around the spot it covers. It closes a gap. It does not change the condition of the roof.

What does a rejuvenation treatment do?

A rejuvenation treatment soaks in. It does not form a layer and it does not patch a spot.

An asphalt shingle is held together by oils. Heat and UV drive those oils out over the years, and a shingle that has lost them goes stiff, cracks when the roof moves, and stops holding its granules. A rejuvenation treatment is sprayed across the roof, absorbs into the shingles, and replaces what the weather took out. The shingle flexes again.

Because nothing sits on top, a treated roof looks the same as it did before. That is the hardest part of selling it. A good result looks exactly like nothing happened.

The short comparison

• Coating: adds a layer over the whole roof. Changes the look. Best suited to flat and low-slope roofs.
• Sealant: closes one gap. Spot repair, not a whole-roof product.
• Rejuvenation: soaks into the shingles you already have and restores flexibility. Changes nothing you can see.

None of the three repairs storm damage, and none of them is a fix for a leak coming through the ceiling. A leak needs a roofer to find where water is getting in and close it.

How to tell what you are being sold

"Roof rejuvenation" gets used loosely, sometimes for products that are coatings with a better name. Four questions sort it out quickly:

1. Does it sit on top, or soak in? If it forms a film, it is a coating, whatever it is called.
2. Will my roof look different afterward? A color change means a layer.
3. Will it stop my leak? If the answer is yes, ask how. Nothing sprayed across a roof finds and closes the one place water is getting in.
4. Will you get on the roof before you quote it? Nobody can judge a shingle from the ground. A price over the phone is a guess.

Which one does your roof need?

Possibly none of them. If your shingles are worn through or storm damaged, the honest answer is a repair or a replacement, and we do neither.

If they are intact but have gone stiff and started shedding granules into your gutters, that is the roof rejuvenation is for. You can read how the treatment works, and the assessment is free. We photograph your shingles, show you the pictures, and tell you which kind of roof you have, including when the answer is that you do not need us.