Commercial asphalt paving contractor

Asphalt paving means building new pavement from the ground up: prepared ground, a compacted aggregate base and hot-mix asphalt on top. That is different from resurfacing, which goes over existing pavement, and removal and replacement, which rebuilds pavement that has failed.

On a commercial site, the paving usually comes with grading, drainage, concrete curb and gutter, accessible parking and striping. We handle that work too, so the grades and transitions are planned together.

• Grading and excavation to subgrade
• Treating or replacing soft ground
• Aggregate base placed, graded and compacted to specified depth
• Hot-mix asphalt placed in lifts and compacted
• Grades set so water drains to the catch basins

Asphalt usually costs less to install, opens to traffic sooner and is easier to repair, which is why most parking lots and private roads are asphalt. Concrete fits where heavy loads sit in one spot, like trash enclosure aprons and truck loading areas. Many sites use both, we build the concrete sitework first then we take care of the paving.

Everything sits on the subgrade, the native ground underneath. If it is soft or wet, more asphalt won't fix it; the pavement will flex and crack from the bottom up. We treat soft ground with cement or lime, or dig it out and replace it, as we did at Longwood Elementary in Hayward.

On top of that goes the aggregate base, which spreads wheel loads and gives the asphalt a stable platform. Base rock that is poorly compacted or is under the recommended standard depth for the traffic load shows up a few years later as cracking and potholes. The base depth is written into our proposal.

Hot-mix asphalt is placed in layers called lifts and has to be rolled while it is still hot. Rolled too late, it won't get dense enough and lets water in, so we plan truck deliveries so the material arrives at the right temperature. We name the mix in the proposal instead of just writing "asphalt."

Grades are set so water flows to the catch basins without ponding, and new asphalt is matched flush where it meets concrete, existing pavement and utility covers.

A single per-square-foot price won't hold from one site to the next. The main factors:

• Area and pavement thickness
• Subgrade condition and any soft ground found
• Demolition, grading, drainage and haul-off
• Access and phasing on a property that stays open
• Concrete, striping and accessibility work in the same project
• Asphalt and fuel prices at the time of the work

The paving itself goes quickly; preparation takes the time. A small area on a ready base can be placed in a partial day, while a site that needs demolition, grading and new base can take several days. Most Bay Area paving happens between spring and early fall, because asphalt can't go down in the rain or on a wet base.

Most commercial paving happens on property that is in use. We phase the work so parking, deliveries and emergency access stay open, and occupants know which areas close and when. At Bay Ship Co. in Alameda, we planned around a working shipyard and finished in a week.

A well-built, maintained commercial lot commonly lasts fifteen to twenty years or more before it needs major work. Drainage, traffic and, above all, maintenance decide where in that range it lands. Seal cracks as they appear, plan a first seal coat within the first few years, then every three to five years after that.