Concrete retaining walls in Monrovia CA - a wall that drains and holds your slope

Most calls start with something you can see, like dirt washing across the walk after a storm, a cut bank that keeps sloughing off, or an old block or timber wall that's started to lean. If that slope sits above a concrete patio or a driveway, the soil and water end up on the slab, so the wall usually has to come first. The price moves mostly with the wall's height and length, then with how much digging, drain work and hauling it takes and whether we can get equipment to the spot. The schedule turns on whether the city wants to review the wall and on curing, the wait while the concrete gains strength before soil goes back against it. When I come out, I measure it and write down what's included, like removal and hauling, so you know what your price covers. We also check with the city before we set a date.

Drainage behind the wall gets most of our attention, because that's what makes a wall fail. I start at the top of the slope and look at where the rain comes from and where it can safely go. Then our crew digs out for the footing, the wide concrete base the wall stands on, and sets rebar, the steel bars that let the wall take the soil's push without cracking apart. We form and pour the footing and the wall, let the concrete cure, and then lay drain rock and a perforated pipe behind it so water runs out to a planned spot instead of soaking in and pushing. The soil goes back in layers, packed as we go, and we haul off what's left.

A wall often turns a slope into flat ground you can finally use, and that's when the next project comes up. We pour concrete pool decks and slabs through our concrete floor installation work on that new ground, and we plan their drainage together with the wall's so the slab doesn't send water back toward it.

Monrovia's grading code calls for retaining walls, built to the Building Code, wherever they're needed to keep a dug or filled slope within its allowed limits, so on a lot that's been cut into, the wall is part of the grading and not just a yard feature. On one hillside home here, the city's Hillside Development Permit named a wall more than six feet high along with grading of five feet or more of cut and fill, which is the soil dug out and brought in to shape the lot. That was one project, not a height rule for every wall, but it shows the kind of wall the city looks at closely. The city's permit page also says it's best to check with the Planning Division about zoning before you apply, which is why, on taller walls or hillside lots, we get the city involved before the design is set.

Many of the walls we're called about here hold back foothill yards, where winter rain runs down the slope and collects behind whatever stands in its way, so I trace that water from the top before we plan the drain. We're based in Monrovia and work across the San Gabriel Valley, and we see the same steep yards and storm runoff on jobs in Sierra Madre and Pasadena.