Retaining wall construction in Brentwood CA - a wall that holds your yard in place

Building a retaining wall in the Bay Area usually costs about $25 to $65 per square foot of wall face, the part you see from the low side, and that's the going rate around here, not our price. Where your wall lands in that range depends mostly on the material, since boulders, stone, wood, poured concrete, interlocking block and railroad ties all price differently, and on whether it needs engineering. I'll give you a number for your own wall once I've seen it.

Plan on an engineer for a wall over 4 feet tall, because one block maker's installation guide says those walls, or any wall local code calls for, should be designed by a licensed professional engineer. Height isn't the only trigger, since industry guidance also calls for an engineer when a wall carries extra load like a sloping bank above it or sits on poor ground. For those engineered walls, the same guidance says the owner or site engineer should hire a geotechnical engineer, a soils specialist, separately for a report, so if yours is headed that way I'll tell you early enough to budget for it.

For most backyard walls I'd pick segmental block, the stacked concrete units, because a rigid poured wall can crack when the ground moves while block flexes and its units shift a little without showing it. The block itself is high-strength concrete that soaks up little water, so it stands up to wear, rot and insects, which is why I'd take it over timber or railroad ties.

Usually yes, since block walls can often reuse the soil already on site instead of trucking in fill. The exception is heavy clay and organic soil, which one block maker's guide doesn't allow as backfill, so if that's what comes out of the hole, we haul it off and bring in fill, and that shows up in the price.

Free-draining gravel behind the face is the main defense, because it carries groundwater off and keeps pressure from building up behind the wall. The surface matters too, and one block maker's specification requires runoff to drain away instead of ponding above the wall or sitting at its base, so whoever you hire should be able to show you where your rain will go.

On a home improvement job in California, a contractor can ask for a down payment of no more than $1,000 or 10 percent of the total contract price, whichever is less. The state licensing board also says every other payment has to be listed clearly in the contract and tied to work already done or materials already delivered to your home.