Asphalt Paving in Union City, CA

Asphalt paving in Union City has to answer to three local conditions: expansive clay soil, a long dry summer followed by a short wet winter, and the Hayward Fault running along the eastern edge of town. The city averages about 15.19 inches of rain a year, with most of it in December, January and February and essentially none in July. A driveway or parking lot here spends half the year baking and the other half sitting on wet ground. Asphalt placed on a well-built base, sloped to shed water, and kept sealed handles that cycle. Asphalt placed on soft clay does not.

The ground under Union City

When Union City studied the soils around its BART station district for its general plan, it found Rincon clay loam under about half of the area, Clear Lake clay under more than a quarter, and Yolo silt loam under most of the rest. The study rates the clay and clay loam soils as moderately to highly expansive. Expansive clay swells when the winter rains soak it and shrinks as it dries out in summer. Pavement laid straight on it, or on a thin skim of rock, rides up and down with the soil until it cracks.

That is why we look at the subgrade before we talk about asphalt. Cost guides describe a typical residential driveway as 2 to 3 inches of compacted asphalt over 6 to 8 inches of compacted gravel base, with more of each for heavier vehicles and 4 inches or more of asphalt for commercial lots. On clay, the base is what separates the pavement from the movement below. Soft spots are dug out and replaced with compacted crushed rock, and the base is graded so water leaves the surface instead of soaking the clay underneath.

Living next to the Hayward Fault

The Hayward Fault runs about 74 miles through the East Bay, through Hayward, Union City and Fremont among other cities. Most of it creeps slowly, generally less than half a centimeter a year, and that slow movement shows up as offset curbs, bent sidewalks and lines of staggered cracks in asphalt. If your property sits near the fault, some cracking follows the ground and will return no matter how well the pavement is built. We tell you when we think that is what we are looking at, and we plan crack sealing as ongoing upkeep rather than selling a repair that cannot hold.

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Union City permits and the property line

In Union City, the public right-of-way begins at the private property line, and a building permit does not cover driveway, curb, gutter or sidewalk work there. That work needs an encroachment permit from Public Works. The city's March 2025 permit packet lists a $72 permit fee plus inspection time at $145 an hour, a faithful performance bond equal to the estimated cost of the work that stays in place for 60 days after the city accepts it, an inspector call at least 24 hours before work begins, and an Underground Service Alert call 48 hours before any digging. Most driveway and parking lot work stays on private property and needs none of this. When a job reaches the apron, curb or sidewalk, we point that out at the estimate so the schedule allows for it.

When paving happens here

Hot-mix asphalt needs warm, dry ground to compact properly, and new pavement needs time to cure before rain and before sealing. In Union City, that points to late spring through early fall for new driveways and lots. Repairs and crack sealing can be done in drier winter weeks, and sealcoating waits for warm, dry days. Planning your project around the season is part of the estimate.

What a typical job includes

• Measuring the area and checking slope, drainage and the curb line
• Removing the old surface and hauling it off
• Digging out soft clay and replacing it with compacted rock
• Grading and compacting the base
• Placing and rolling hot-mix asphalt to the thickness in your quote
• Finishing edges at the garage slab, walks and apron
• Telling you when to drive on it and when it can be sealed

Union City is home base. We also work in Fremont, Newark, Hayward, Castro Valley, San Leandro and the unincorporated Eden Area communities, and across the Tri-Valley in Pleasanton, Dublin and Livermore. Each city runs its own right-of-way permits, and the unincorporated areas go through Alameda County Public Works instead, so the paperwork changes when you cross a city line. Soil and terrain change too, from the bay-edge flats of Newark to the canyons of Castro Valley. The town pages explain the local details.