What detergent works for a DIY pre-seal clean on Ottawa asphalt?

For DIY pre-seal cleaning of Ottawa asphalt driveways, use a strong degreasing dish detergent like Dawn or a commercial driveway cleaner mixed with hot water — avoid harsh chemicals that can damage the asphalt binder.

The most effective approach is mixing 1/2 cup of Dawn dish detergent (or similar grease-cutting formula) with 5 gallons of hot water. Dawn's degreasing agents break down oil stains, tire marks, and the film of road salt residue that accumulates on Ottawa driveways over winter. Apply the solution with a stiff-bristled brush and scrub in sections, working from the top of the driveway downward.

Commercial driveway cleaners like Simple Green Pro HD or Krud Kutter are formulated specifically for asphalt and work well for heavier staining. Mix according to package directions — typically 1 part cleaner to 4 parts water. These products are more expensive than dish detergent but handle stubborn oil stains and salt residue more effectively.

Ottawa-specific cleaning considerations make this step critical. Road salt and de-icing chemicals used from November through April leave a white, chalky residue that prevents sealer adhesion. This salt film must be completely removed or the sealer will peel within months. Additionally, Ottawa's clay soil tends to stick to asphalt surfaces during spring thaw, creating a muddy film that also interferes with sealer bonding.

Avoid using harsh chemicals like muriatic acid, bleach, or petroleum-based solvents on asphalt. These can soften or dissolve the asphalt binder, creating weak spots that will fail after sealing. Similarly, avoid pressure washing at high pressure (above 1500 PSI) as it can damage the asphalt surface and create texture that shows through the sealer.

Proper cleaning sequence is essential: sweep loose debris, apply detergent solution, scrub with a stiff brush, rinse thoroughly with garden hose, and allow 24-48 hours of dry weather before sealing. The surface must be completely dry — any trapped moisture will cause the sealer to bubble and peel during Ottawa's next freeze-thaw cycle.

For oil stains that resist detergent cleaning, sprinkle cat litter (clay-based) on fresh spills to absorb oil, then sweep and clean with detergent. Older, set-in oil stains may require a commercial oil stain remover before the general cleaning.

Need help finding a driveway contractor for professional sealing? Ottawa Driveways can match you for free with local paving professionals who handle the entire cleaning and sealing process.