How soon after cleaning do pavers look their best?

The sealers whose data sheets were read do not go on looking like the finish they become. Techniseal's Natural Look (NS) Protector is “milky white in its container and will become clear once dry.” SEK-Surebond's SB-1300 “has the consistency of water, is milky white when applied and dries clear with matte finish.” Seal 'n Lock's Super-Wet “appears white when initially applied, but dries crystal clear.” Three makers, three products, the same sequence.

A rinsed surface tells the same story from the cleaning side: wet pavers read darker than dry ones, for the ordinary reason that a wet surface reflects light differently than a dry one, and a driveway photographed while it is still shedding rinse water is not showing the color it will settle into.

ICPI's instruction for checking the result of an efflorescence cleaning, the whitish deposit a proprietary remover is used on, is to wait: “Results can be verified after letting the area dry for at least 24 hours.”

A sealer follows the same pattern one step later. The makers place the clear finish after drying, and ICPI describes most sealers darkening the paver surface and enhancing its color, so a fair look at either step, the clean or the seal, is a dry look. What a cleaning takes off the surface, and how ICPI tests a cleaner on a small area first, is covered at what a paver cleaning removes.

Two faults show once the sealer has dried. The Decorative Concrete Council's guide, written for concrete, says a sealer “allowed to puddle, or is overlapped, will dry with a darker color, resulting in a blotchy appearance,” and Seal 'n Lock's guide says to “always back roll, broom, or blow the sealer for consistency to prevent blotching”. What a blotchy result looks like, and what causes it beyond puddling, is answered at why a patio looks blotchy after sealing.

Cleaning shortcuts show up the same way. Techniseal's Natural Look (NS) sheet warns that “Inadequate surface cleaning can result in uneven finish,” and SEK-Surebond's site preparation bulletin says that if the step is skipped, “any dirt, spots and residue on the substrate will be sealed in”. How much darker a sealed, dried surface reads than the same pavers bare is its own question, at how much darker sealer makes pavers, and the gloss a film-forming product leaves once it has cured is what the trade calls the wet look.