How can you tell if pavers were sealed before?

Techniseal's WL1-2 data sheet writes the screening test as a set of instructions, not a description: "Sprinkle a few drops of water on surface. If water is absorbed, move on to the next point. If water is repelled, do not apply this product."

The same maker's product guide reads the other result: "beading water on the surface is a good sign that the pavers are still sealed." A good sign, in its words, not proof. Neither line checks a brand; both check whether something on the surface still turns water away.

ICPI's description of what a sealer does is the reason the test works: "Sealers reduce the intrusion of water, stains, oils and dirt into the paver surfaces." A film, or a penetrating barrier, that still does that turns a drop of water into a bead sitting on top of the paver instead of letting it sink in.

A bare paver has no such barrier, so the same drop spreads and darkens the surface as it soaks in. The bead and the soak are the same mechanism read two ways: one surface has a repellent layer between the water and the paver, and one does not.

A bead points to a repellent film or barrier. It does not say which product made it, which family it belongs to, or how many coats went down; no source read here ties a water reading to a brand. Whether a new sealer may go over what is found is its own question, answered on sealing over an old sealer, and it is settled by the new product's label: Techniseal's WL1-2 sheet, for one, sends any unknown coating to the appropriate stripper first. How much life an old film has left is covered on how long paver sealer lasts.

A bead is not proof the surface is watertight either; whether sealing keeps water out altogether is answered on whether sealing makes pavers waterproof. What was actually applied, and when, lives only in the earlier applicator's or previous owner's paperwork.

The sheen left behind narrows the guess without settling it. ICPI says most sealers darken the paver surface and enhance its color, that acrylics create a gloss on the surface, and that silane and siloxane sealers produce a flat, no-gloss finish. A gloss, the finish sold as a wet look, fits a glossy chemistry such as an acrylic or a urethane. A flat finish settles less: natural look names a finish rather than a chemistry, sold on penetrating and film-forming products alike, and bare pavers are flat too.

The two families, and what each one is built to do once it is confirmed, are laid out in full on what a sealer does and the two families it comes in. A driveway and the walkway beside it do not have to share the same answer either, which is its own question on sealing a driveway but not a walkway.