Concrete retaining walls in Sunnyvale CA - built to drain and hold back your soil

Most people call us when a bank is slumping onto a patio or path, when an old timber or block wall has started to lean, or when they'd like a level yard where there's a slope, often with concrete steps to get between the two levels. The price moves mainly with the wall's height and length, how much soil has to come out, how easily we can get a concrete truck or pump to the spot and whether a driveway or building sits above the slope, because each of those adds digging, steel or forms. The schedule depends on whether the wall needs an engineer's design and a permit before we start. It also depends on curing, the time the concrete needs to gain strength before we fill soil in behind it. Your estimate puts the scope and the price for your wall in writing.

We start by looking at the slope, what sits above it and where the rainwater comes from, because that tells us how the wall has to drain. Our crew then digs out for the footing, the wide base the wall stands on, down to firm ground. We set the forms and tie in rebar, the steel bars that let the wall and footing resist the push of the soil together. We pour the footing and wall, leave weep holes, which are small openings near the bottom that let water out, and give the concrete time to cure before anything leans on it. Then we lay a perforated drain pipe along the base behind the wall and backfill with clean gravel, so water drops to that pipe instead of building up against the concrete. After that we pack the soil above it in layers and clean up. Most of our attention goes to that drain, because trapped water is what makes walls lean and fail. If a budget needs trimming, I'd rather keep the face of the wall plain than skimp on the footing or the drainage, since those can't be reached later without taking the wall out.

A wall usually changes what you can do with the ground beside it. Once a slope is held back, there may be room for a concrete pool deck around a new pool, or for concrete floor installation under a shed or studio. Planning those with the wall lets us send all the water to one place.

Whether a retaining wall needs a permit is up to the City of Sunnyvale, which reviews building plans through its One-Stop Permit Center. The answer depends on the project, so we don't assume either way. Every permit step with the city runs online, from the application and uploaded documents to inspections and payment. When your wall needs a permit, we handle the application and the inspections with the city and keep you informed. When it isn't clear, we check with the city's permit office before we start.

If your lot sits inside a state Seismic Hazard Zone, the state has found that weak soil or rock may lie beneath it. That ground can fail in an earthquake unless proper precautions are taken during grading and construction, so we raise it early on any taller wall. On Sunnyvale's flatter lots, most walls we're asked to build are lower ones for raised beds, sunken patios or driveway cuts. Jobs in Cupertino and Saratoga more often climb into the hills and call for taller walls.