Sealcoating in Union City, CA

Sealcoating is a thin coat of liquid sealer spread over asphalt to protect it. Sun oxidizes the binder in asphalt and turns it gray and brittle; water gets into the surface and works its way down. A good sealcoat slows both, restores the dark color and makes the surface easier to clean. It does not fill potholes, fix a failing base or level a sunken area, so we repair those first.

Timing in the East Bay

Sealer needs dry weather to cure. HomeGuide recommends applying it between 50 and 95 degrees in dry conditions, and keeping traffic off for 12 to 72 hours. With Union City's rain concentrated from November through March, sealcoating is a late spring through fall job. New asphalt should cure for several months before its first coat; HomeGuide suggests three to six months.

How often to seal

Published guidance ranges from every two to ten years depending on the sealer and the climate. In practice, we look at the surface: when the color has faded to gray, small surface cracks are opening and fine aggregate is showing, it is time. Sealing too often can build up a layer that cracks and peels, so more is not always better.

Sealer types

Coal tar and asphalt emulsion sealers are the two common families. HomeGuide notes that many areas have banned coal tar sealers because of health and environmental concerns. We use asphalt-based emulsion sealers and can discuss additives for sand and traffic resistance on lots.

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Prep is most of the job

The surface is swept and blown clean, oil spots are treated so the sealer sticks, grass and weeds are cut back from edges, and cracks are filled before sealing. On lots, we plan the order so traffic can be routed around wet areas.

Keeping it out of storm drains

Union City's encroachment rules state plainly that non-storm water must not reach storm drains. Sealcoat is applied with inlets and gutters protected, and equipment is cleaned where rinse water stays contained.

Driveways versus lots

On a driveway, sealcoat is mostly about protection and appearance. On a parking lot, it also restores contrast so new striping stands out, and it gives a lot a consistent surface after patches. Lots usually get a sand-additive sealer for traction and are sealed in sections so part of the lot stays open.