Sealcoating in Portland, OR

Sealcoating is a thin protective coat applied over asphalt to shield it from water, sun and oil drips and to restore its dark finish. In Portland, the water part is what matters most. Asphalt that has gone grey and porous lets rain work into the surface, and cracks left open through November, December and January let it reach the base. A sealcoat over filled cracks, applied before the wet season, is one of the lowest-cost ways to stretch a driveway's life.

Why timing matters here

Sealcoat has to dry and cure, and it needs help from the weather to do it. HomeGuide says to apply it to dry pavement when temperatures are between about 50 and 95 degrees, with 12 to 72 hours before cars go back on it. Portland's dry season, roughly mid-June to early September, is the natural window, with July and August averaging about half an inch of rain each at the airport. We book sealcoating for that stretch and watch the forecast closely.

Prep comes first

Sealer will not stick to moss, dirt or oil. We blow off and scrape the surface, clear fir needles and moss from shaded areas, treat oil spots, and fill cracks with hot-applied crack sealant before the coat goes on. Shaded driveways under big firs and maples stay damp longer and grow moss, so they need extra cleaning and dry-time attention.

New driveways

New asphalt needs to cure before it is sealed. HomeGuide advises waiting 3 to 6 months, and its FAQ suggests a first seal after about a year. For a driveway paved in a Portland summer, that usually means sealing the following summer.

How often

HomeGuide's FAQ suggests every 2 to 3 years for driveways, while its broader guidance runs from 2 to 10 years depending on the sealer and climate. In practice, we look at the surface: when it has faded to grey, the texture is opening up or new cracks have formed, it is time.

Parking lots

Commercial lots are sealed in sections so the business can stay open, then restriped. HomeAdvisor puts professional parking lot sealcoating at about $0.15 to $0.30 per square foot.