Should I use coal-tar or asphalt-based sealer in Ottawa?

Use asphalt-based emulsion sealer for your Ottawa driveway. Coal tar sealer, while offering superior chemical resistance, contains harmful PAHs (polycyclic aromatic hydrocarbons) and is increasingly restricted across Canada due to environmental and health concerns.

Asphalt emulsion sealers are the standard choice for Ottawa residential driveways and provide excellent protection against our extreme climate conditions. These water-based sealers restore the black appearance of weathered asphalt, fill minor surface voids, and create a protective barrier against water penetration, UV oxidation, and salt damage. In Ottawa's harsh freeze-thaw environment, the primary goal of sealing is preventing water from penetrating the asphalt surface where it can freeze, expand, and create cracks.

Ottawa's climate demands regular sealing every 2 to 3 years regardless of sealer type. Our 50+ annual freeze-thaw cycles, road salt exposure from November through April, and intense summer UV radiation break down any sealer over time. Asphalt emulsion sealers typically last 2 to 3 seasons in Ottawa before requiring reapplication. The key is consistency — a driveway sealed every 2 to 3 years with quality asphalt emulsion will last 20 to 25 years, while an unsealed driveway in Ottawa develops extensive cracking within 5 to 7 years.

Application timing is critical in Ottawa. Asphalt sealer must be applied when daytime temperatures are consistently above 15°C with no rain forecast for 24 to 48 hours. This typically means late May through early September in our climate. Never seal in cool, damp conditions — the sealer won't cure properly and will remain soft, tracking onto shoes and vehicles while providing minimal protection.

Prepare the surface thoroughly before sealing. Clean the driveway with a stiff brush or pressure washer, allow it to dry completely, and fill any cracks wider than 5mm with hot-pour rubberized crack filler before applying sealer. Two thin coats applied with a squeegee or roller provide better coverage and durability than one thick coat.

Cost considerations favor asphalt emulsion sealers at $0.15 to $0.35 per square foot for DIY application or $0.40 to $0.80 professionally applied. This represents the single best maintenance investment for Ottawa asphalt driveways — spending $200 to $500 every 2 to 3 years on sealing prevents thousands in premature replacement costs.

If you're unsure about the previous sealer type used on your driveway, test a small inconspicuous area first. Mixing different sealer chemistries can cause poor adhesion and peeling.

Need help finding a driveway contractor for professional sealing? Ottawa Driveways can match you with local paving professionals who understand our climate requirements.