Why is my paver sealer peeling?

Euclid Chemical, writing about concrete sealers, describes the sequence as one event running into the next: “Heavy coats of sealer, or a buildup of sealer applied numerous times over the years, will cause moisture to become entrapped under the sealer”. The sealer then loses its adhesion to the surface below it. That trapped moisture and air reads to the eye as a milky white, and in time the sealer peels or flakes off the surface.

Techniseal publishes a version of the same sequence for its own paver Protectors. It writes that they are microporous and let moisture out; too much Protector applied too often builds up, the film loses that microporosity, and Techniseal states that loss “could lead to the whitening and peeling of the film”. What a surface with too much product on it looks like is a related but different question, covered under what over-sealing looks like on pavers.

A peeling film is not always about what went on top of the pavers; sometimes it is about what was already on them. SEK-Surebond's site preparation bulletin puts the consequence in one sentence: skip the cleaning step and any dirt, spots and residue on the surface get sealed in underneath the film, which SEK-Surebond says makes for an unsightly look and could affect the sealer's own performance.

ASCC's Decorative Concrete Council, writing about decorative concrete, adds a specific case: sealing over oil-soaked spots “may result in poor adhesion or inadequate penetration of the product,” and poor adhesion is the same lost grip this page is about.

Heat changes how a solvent-based sealer behaves on the day it goes on. The Decorative Concrete Council's sealer guide, written for decorative concrete, puts it in one sentence: “Using a solvent based sealer in hot weather or in direct sunlight can result in bubbling, which in turn leads to peeling or flaking.” What forms a bubble in the first place is its own question, answered under what causes bubbles in a paver sealer.

A new coat over an old one carries its own risk. Techniseal instructs installers to wait until a previously applied sealer of another brand has worn away before its own Protector goes on, and when a water-based Protector goes over a solvent-based sealer, there must be no sealer left on the surface at all; beading water instead of soaking in is Techniseal's own sign that pavers are still sealed.

The Decorative Concrete Council lists incompatible sealers layered over one another, “causing trapped solvents between sealer layers,” among the causes of a sealer turning white, and adds: “Re-sealing always poses a risk because the original sealer used is typically unknown, not only the manufacturer, but the type (water or solvent).” Its advice before any recoat is a thoroughly clean, dry surface, because moisture caught between layers, the guide says, causes adhesion failures.

Two glossary words sit close to this failure: delamination, a coating separating from what is under it or from another layer of itself, and peeling, the word for the film coming away. A film that turns milky before anything lifts is a separate question, answered under why sealed pavers turn milky or white.

None of these causes says who applied the sealer, and no page can tell which one is at work on a particular driveway. The fix belongs to the sealer's maker and its published instructions; ICPI, writing about a sealer that has clouded, says “Consult your sealer supplier for advice on treating this situation.” What stripping means, and who publishes how it is done, is defined on its own page.