Concrete parking lot building in Orinda CA - a lot that drains where it should

Most folks who call about a lot have outgrown their gravel or an old surface, and they want parking that holds up to the cars and trucks it sees every day. What moves the price is mostly how much dirt has to move and how much drainage the lot needs. What moves the schedule is usually permits, since a bigger lot or a lot of digging can bring in grading and drainage review before anyone breaks ground. If your job needs a permit, we can pull it as your contractor and handle the paperwork and inspection calls for our part, and the on-site estimate is where you get your own figure in writing.

Most of the work on a lot is the dirt and the water, so we plan how much earth moves and where the runoff goes before we ever talk about the concrete. We dig out the soft stuff down to firm subgrade, the ground the slab rests on, then bring in base rock and pack it in layers instead of raking it smooth, because a raked base settles under the first heavy truck. We set the forms so the whole lot falls away from buildings and toward wherever the water's meant to go. We pour early in the day when we can, since midday heat dries the top too fast and leaves it weak and dusty later, and we give it a broom finish, a lightly brushed texture so tires and shoes grip when it's wet. Concrete cracks a little, so we cut control joints, shallow grooves that give the slab a place to crack in a straight line instead of wherever it pleases. Then it cures, the wait while it hardens enough to carry cars, and we keep traffic off until it's ready. If the budget gets tight, I'd rather trim the finish than the base, because nobody sees the base on pour day, but like we said on the farm, a barn's only as good as what it sits on.

A lot rarely stands by itself. Anything that has to stand up at its edge, like light poles, a carport or a gate, sits on concrete footings that we pour before the slab goes in. And if a building next to the lot has settled, often because water off the old surface soaked the ground beside it, we'd look at foundation raising before we pave up against it.

Size is what changes a parking lot job here. Contra Costa County's stormwater permit generally requires roads, sidewalks and other facilities that create or replace 5,000 square feet of hard surface, the kind water can't soak into, to add stormwater facilities sized to the county's set criteria, so a larger lot can carry real drainage work in its design. In Orinda, work that needs a building permit also goes through the city's Planning Department, which checks zoning, unless the project is on the city's exempt list. Anything built in the public right-of-way, like where your entrance meets the street, needs an encroachment permit from the City of Orinda Public Works Department. We sort out which of these touches your lot early on and check with the right office before we start, rather than guess.

Lots around here are often cut into a hillside or sit below a road, so water is already headed somewhere before we show up, and our job is to give it a better route than across the slab or toward a building. We see the same slopes and runoff on jobs in Moraga and Lafayette, and we plan for them the same way.