How to Clean Pavers Before Sealing

Sealer protects pavers, but it also locks in whatever is on the surface. Dirt, mold or a white haze under fresh sealer stays there until the sealer wears off. Good cleaning is the most important step of any sealing job.

What you need

• A pressure washer, ideally with a surface cleaner attachment for even results
• A paver cleaner suited to the stains you have
• A stiff brush, a broom and a leaf blower
• Joint sand or polymeric sand to refill the joints
• Gloves and safety glasses

Step 1: Clear and sweep

Move furniture and planters, then sweep or blow off leaves and loose dirt. Pull weeds from the joints.

Step 2: Treat stains first

• Oil and grease: a degreaser made for pavers, scrubbed in and left to work before rinsing.
• Rust: a rust remover for masonry. Rust often comes from well water sprinklers or metal furniture.
• Mold, mildew and algae: a cleaner made for organic growth, common on shaded pavers in Florida.
• White haze (efflorescence): salts rising out of the pavers. Use an efflorescence remover and rinse well.

Always follow the product label and test a small hidden area first.

Step 3: Pressure wash

Wash at a pressure that cleans without damaging the surface. Keep the nozzle moving and hold it at a low angle, or use a surface cleaner to avoid stripes. Too much pressure can etch pavers and blast out the joint sand.

Step 4: Let everything dry

This is where many jobs go wrong. Pavers need to be fully dry before sealing, usually at least 24 hours of dry weather, longer in shade or after heavy rain. Sealing damp pavers is a common cause of cloudy, white patches.

Step 5: Refill the joints

Washing removes some joint sand. Sweep new sand into the joints. If you use polymeric sand, follow its directions for compacting and wetting, and make sure no residue is left on the paver surface before sealing.

Step 6: Seal

Once clean, dry and re-sanded, the pavers are ready. Apply thin, even coats in the right weather.

Want it done for you? Post your job and local pressure washing and sealing pros send bids. Cleaners, sealers and surface cleaners are in the CSI Store.