Can new sealer go over an old sealer of a different kind?

The labels read here put three questions to an old coat before anything goes over it: what it is, whether it wore evenly, and whether it is peeling. The answers decide whether a new coat is allowed on at all.

Techniseal's WL1-2 data sheet puts the first question in its own application line: apply the Protector only to bare material, or to material previously sealed with that product or its named predecessors. Seal 'n Lock's guide asks the second and third together, permitting its Super-Wet-Look over an existing sealer only "as long as there is no delaminating (peeling) of existing sealer and is worn evenly."

Where there are shiny patches, or areas gone white from another sealer, the same guide recommends stripping the existing sealer first rather than coating over it.

Within its own line, Techniseal's rule is narrow. Its WL1-2 data sheet allows the Protector only on bare material or on a surface already sealed with that product or its named predecessors.

A different brand gets a conditional yes. Techniseal's guide says pavers sealed with another maker's product can take its Protector once that sealer is worn, normally about two years, or maybe less for an economical one. Whether that earlier film is even still there is answered by the water test used to tell whether pavers were sealed before.

Techniseal draws a separate line at the carrier. Its product guide says that where pavers carry a solvent based sealer and a water based Protector is going on, it is important to make sure no sealer is left on the pavers. The guide gives the condition, not a reason for it.

SEK-Surebond handles the question for its own SB-1300 with a product rather than a wait: "Use Efflo Off for efflorescence cleaning and SureStrip to remove previously applied sealer, other than SB-1300." That line covers any earlier sealer that is not SB-1300, whatever it was carried in.

Delamination is the word Seal 'n Lock's guide pairs with peeling: an old film lifting away from the paver rather than wearing down evenly on it. A peeling coat, or one with shiny patches beside dull ones, is not what that guide calls worn evenly, and why a coat gets to that state is its own question, covered on why paver sealer peels.

Acrylics and urethanes do not age the same way either, and a driveway with an old urethane film is a different question from one with an old acrylic film; ICPI's end-of-life difference between the two is set out on how paver sealing works.

When nobody can say what the old sealer is, Techniseal's instruction skips the wait entirely: "With the appropriate Techniseal® stripper, remove any unknown coating that was previously applied." The same sheet says not to apply a Protector over a blotchy or hazed surface. Stripping is the trade's word for that step. What the old coat actually was is on the previous applicator's paperwork, if anyone kept it; a water test only shows whether a repellent film is still there.