Can a driveway be sealed without cleaning it first?

No sealing instruction cited here allows a sealer over an uncleaned surface. ICPI's sealing procedure opens with the requirement: “All dirt, oil stains and efflorescence must be removed prior to sealing.” SEK-Surebond's site preparation bulletin applies it to new work and old alike: “When it comes to applying sealer to a new or existing hardscape project, you must properly prepare and clean the surface first.”

ICPI also fixes the sealer's place in the sequence: “Like stabilizers, application of a sealer follows stain removal, efflorescence removal and overall surface cleaning.” The sealer is the step after the cleaning, never a stand-in for it.

Skip the cleaning, SEK-Surebond warns, and dirt, spots and residue are sealed in; how that looks, and whether a sealer can cover a stain, is answered at will sealing hide stains on pavers.

ICPI's cleaning order starts narrow: “Stains on specific areas should be removed first. A cleaner should be used next to remove any efflorescence and dirt from the entire pavement.” SEK-Surebond's numbered list does the same at its second step, “Pre-treat and spot clean any stains that require special attention,” naming oil and food stains, and it tells the reader to test the cleaner first so it will not harm the paver surface.

Which cleaner a stain gets, and whether it harms that paver, is the product label's answer and the test's. Oil is a case with its own page: can paver cleaning remove oil stains.

With the spot stains treated, the cleaning widens to the entire surface. SEK-Surebond's steps scrub it “with a natural fiber brush to agitate and break down stains,” then “use a pressure washer (hot water preferred) or flat surface cleaner to draw out and further break down stains plus any imbedded sediment.”

ICPI's professional sequence for concrete pavers has the same shape without the brush: the cleaner goes on and sits for an appropriate time, then a high pressure sprayer rinses it off, and ICPI says that pressure loosens dirt without the need for scrub brushes. The pressures each paver material tolerates are set out on the paver cleaning page, and why water on its own does not count as the cleaning is explained under how paver sealing works.

SEK-Surebond's rinse step sets its own finish line: “Rinse the treated area thoroughly making sure no cleaner residue remains on the surface.” ICPI adds that the final rinse is water only, and that a large amount of water matters more to rinsing than high pressure.

The rinse matters to the sealer for the same reason the scrub does. Cleaner left on the pavers is residue, and residue is on SEK-Surebond's list of what gets sealed in. ICPI puts the goal of the whole cleaning in two sentences: “Removal of accumulated dirt and efflorescence is the objective of cleaning. It is essential in preparing the pavers for sealing as well.”

A clean surface is not yet ready for a sealer. ICPI and SEK-Surebond both set a dry condition of at least 24 hours before most sealers go on, and why a paver can look dry before it meets that condition is answered at pavers that look dry but are too wet to seal.

Whether any sealer is made to go on damp pavers right after a cleaning is taken up at a sealer for damp pavers right after cleaning. Efflorescence is on ICPI's list of what must be removed before sealing, and whether pavers that show it can be sealed is covered at sealing pavers with efflorescence.