Retaining Wall Contractor in Los Angeles and Across Southern California
Green Design and Build is a licensed residential general contractor (CSLB #1110975) that designs, engineers, permits and builds retaining walls for homeowners across Los Angeles County, the San Fernando Valley, Orange County, Ventura County, western Riverside County and western San Bernardino County. This page explains what we build, why the walls we are called to inspect failed, when you need a permit and an engineer, and what a wall costs installed.
A retaining wall holds back a wedge of soil that is trying to move downhill, every drop of water that soil absorbs, and whatever sits on top of it. Most failed walls were built as if only the first of those three existed.
Wall types we build
We match the wall to the height, the load behind it and the budget, and we will tell you when the cheaper type is the right one.
- CMU block with rebar and grout. The standard engineered wall in Southern California. Block on a poured footing, vertical rebar doweled into the footing, cells grouted solid, finished with stucco, precision block or veneer. What most 4 to 8 ft residential walls should be.
- Poured concrete. A formed, reinforced stem on a footing. Stronger per inch than block; the right choice for tall walls, heavy surcharge and curves. Costs more because forming is labor.
- Segmental (interlocking) block. Dry-stacked, battered blocks that rely on their weight and, above about 3 ft, on geogrid tied back into the compacted backfill. No footing pour, no grout, and the best value for garden and terrace walls under 4 ft.
- Timber. Pressure-treated timber for small garden walls only, usually under 3 ft. We will not build a timber wall that holds up a driveway or sits below a slope.
- Stone veneer over block. A CMU structural wall with natural or manufactured stone on the face. You are paying for the block wall plus a finish.
A wall is often part of a larger project; see the outdoor living hub for how walls, pavers, concrete and patio covers fit together.
What a retaining wall actually has to do
Three jobs, and the wall fails if any one is skipped.
Hold the soil. Soil pressure builds with the square of the height, so a 6 ft wall carries closer to four times the load of a 3 ft wall. That is why a 3 ft wall can be a stack of blocks and a 6 ft wall is a structure with a stamped drawing.
Drain the water. Saturated soil weighs more and pushes harder, and water pressing on the back of a wall adds a load it was never sized for. Every wall we build gets a perforated pipe at the footing, a column of clean gravel behind the stem, filter fabric between gravel and native soil, and either weep holes or a solid pipe run to daylight. Weep holes with no gravel behind them are decoration.
Resist the surcharge. Anything on top of the retained soil within a horizontal distance roughly equal to the wall height is a surcharge: a driveway, a pool, a shed, or a slope that keeps rising above the wall. A surcharge changes the engineering and triggers a permit at any height.
Why retaining walls fail
No drainage. The most common one. Built tight against native soil with no gravel and no pipe, the wall bows out from the bottom third up the first wet winter: a horizontal crack a course or two above grade and a stem out of plumb.
No footing, no engineering. Block stacked on a shallow strip, so the wall slides or rotates. Or a 5 ft wall built from a 3 ft wall’s details: 8-inch block, bar every 32 inches, half the cells empty. It looks fine for two or three years.
Hillside soil creep. On slopes in the Santa Monica Mountains, the Verdugos and the Puente Hills, the top few feet of soil move downhill a fraction of an inch a year, and a wall that ignores that eventually carries the whole slope. This is why hillside walls need a geotechnical engineer.
Expansive clay in the Valley. Much of the San Fernando Valley sits on clay that swells when wet and shrinks when dry. The swell pushes on the wall every winter; the shrink opens gaps that fill with water. The fix is drainage, non-expansive backfill and a wall designed for the higher pressure.
Backfilled too early. A crew that backfills a block wall the day after grouting has cracked it before you see it. Our rule is no backfill against a grouted wall for seven days, and then in compacted 8-inch lifts, not one dump.
Engineering and permits
The short version: retaining walls over 4 ft, or any wall carrying a surcharge, need a permit, and a permitted wall needs an engineer’s stamped drawing and calculations.
The detail that catches people: the 4 ft is measured from the bottom of the footing to the top of the wall, not from grade. That is the wording of the California Building Code exemption as applied in the City of Los Angeles and by Los Angeles County for unincorporated areas. A wall showing 3 ft 6 in above grade on an 18-inch footing is a 5 ft wall to the plan checker.
Hillside lots add a layer. In the City of Los Angeles, hillside grading work requires exploration by a soils engineer and an engineering geologist under the grading code, so a wall on a designated hillside lot usually means a geotechnical report before the structural engineer can size it. Cities differ, and we confirm the requirements for your address before we price the job.
We handle it under one roof: survey, geotechnical report where required, structural engineering, the LADBS or city submittal and inspections. The two inspections that matter on a block wall are the footing before the pour and the rebar before the grout pump arrives.
Grading, drainage and foundations
A retaining wall changes where water goes, so before we design one we look at where roof water discharges, where the yard ponds and where the neighbor’s slope drains. The wall’s drain line has to go somewhere, usually a yard drainage system run to the street or a dry well; see landscaping and irrigation for how we grade and drain the rest of the yard.
A wall within a few feet of the house, a wall holding up the pad the house sits on, or a cut into the slope below the house is foundation work with a retaining wall attached, and the engineer designs both together.
How we build a retaining wall
- Survey, geotechnical report and engineering. Heights, lengths, what sits above and below the wall, and stamped drawings where the height or surcharge requires them.
- Permit through LADBS or the city.
- Excavation. Cut back the slope, bench it, shore it where the cut is deep.
- Footing. Formed, rebar on chairs, dowels set for the stem, inspected, poured.
- Stem. Block laid and grouted in lifts, or concrete formed and poured. Inspected before grout.
- Waterproofing and drainage. Damp-proofing on the soil side, pipe at the footing, gravel column, filter fabric.
- Cure, backfill in compacted lifts, then finish. Stucco, veneer, cap, and the fencing or guardrail on top where the drop requires one.
Where we build retaining walls
We build across our service area, and the walls differ by region. In the San Fernando Valley and the hillside neighborhoods of Los Angeles County, most calls are for slope walls on cut lots in Encino, Sherman Oaks and Woodland Hills, where clay soil and hillside review shape the design. In Orange County, the typical job is a terrace or slope wall on a graded tract lot in Irvine, Mission Viejo or Yorba Linda, where the HOA reviews height, finish and color before the city does. In Ventura County, foothill lots in Thousand Oaks, Moorpark and Simi Valley sit on slopes graded decades ago and need walls to reclaim usable flat yard. In western Riverside County and western San Bernardino County, in Corona, Murrieta, Rancho Cucamonga and Ontario, lots are larger and walls run longer and lower: property-line walls, planter walls and walls that separate a pool level from a lawn.
Timeline
A garden wall under 4 ft with no permit: one to two weeks once we start. An engineered wall: two to four weeks for engineering, two to eight weeks for plan check depending on the city and the geotechnical report, then two to four weeks of construction. Hillside walls run longer at every step.
What a retaining wall costs in Southern California
Walls are priced by the square foot of face, including the buried footing, because height decides the footing, the rebar and the block thickness. Worked examples are on our retaining wall cost page.
| Wall type | Installed cost per sq ft of face | Notes |
|---|---|---|
| Segmental (interlocking) block | $30–$60 | Best value under 4 ft. Geogrid above that. |
| CMU block, rebar and grout | $35–$75 | The standard engineered wall. Stucco or precision finish. |
| Poured concrete | $45–$95 | Tall walls, heavy surcharge, curves. |
| Stone veneer over CMU | $70–$140 | Block wall plus a finish. |
| Timber (garden walls under 3 ft) | $20–$40 | Not for driveways or slopes. |
| Structural engineering | $1,500–$8,000 per project | Stamped plans and calculations. |
| Geotechnical report | $3,000–$8,000, more on steep hillside lots | Borings, lab work, recommendations. |
| Permit and plan check | $500–$2,500 | Varies by city and valuation. |
| Demolition of a failed wall | $25–$60 per linear foot | Includes haul-off. |
| Drainage tie-in to yard system | About $90 per linear foot | Solid pipe to street or dry well. |
| Difficult access | Adds $500–$1,500+ | Wheelbarrow and pump instead of Bobcat. |
These are typical Los Angeles budgeting estimates, not a price list or a quote. Your project can come in lower or higher depending on the house, the scope and the finishes; the only real number is a written proposal after a site visit.
Access and what is already there move these numbers more than material. If an excavator cannot reach the wall line, spoil comes out by wheelbarrow and concrete goes in by pump. A failed wall has to come out, and the slope behind it usually has to be cut back further than the first builder did.
Frequently asked questions
Do I need a permit for a retaining wall in Los Angeles?
Any wall over 4 ft measured from the bottom of the footing to the top, or any wall of any height that supports a surcharge such as a driveway, a slope above or a structure, needs a permit and engineering. That is the City of Los Angeles rule and the Los Angeles County rule for unincorporated areas; other cities have their own thresholds, and hillside lots add geotechnical review. We confirm the requirement for your address before we price the wall.
Can you fix my leaning retaining wall instead of replacing it?
Sometimes. A wall out of plumb by an inch or two with no cracking can occasionally be saved by adding drainage behind it and relieving the load. A wall with a horizontal crack, a rotated stem, or block sheared at the footing cannot; the reinforcing has already yielded. We will tell you which one you have after a site visit, and if the honest answer is replacement, we will say so.
What is the best type of retaining wall for a hillside in Southern California?
For most residential hillside walls over 4 ft, a CMU block wall with grouted cells on an engineered footing, or poured concrete where the load is heavy. Segmental block works below 4 ft and with geogrid above it, but the geogrid needs room behind the wall that a tight cut lot may not have. The geotechnical report decides more than the material does; it sets the soil pressure the wall is designed for.
How long does a retaining wall last?
A properly engineered and drained block or concrete wall should outlast the house. The walls we replace are usually 15 to 30 years old and failed because of water, not age. Timber walls last 10 to 20 years depending on drainage and contact with wet soil. Segmental block lasts as long as its base and geogrid do, which, done correctly, is decades.
Does a retaining wall need drainage if my yard is dry?
Yes. Southern California gets almost all its rain in a few winter storms, and that is when the soil behind a wall saturates. A wall that has been fine through five dry years can fail in one wet one. Every wall we build gets a drain pipe at the footing, gravel behind the stem and a route for the water to leave, regardless of how dry the yard looks in September.
Can a fence go on top of a retaining wall?
Yes, and it changes the engineering. A fence adds wind load at the top of the wall, and a guardrail is required where the drop is more than 30 inches. The engineer designs the wall for the fence, and we set the post sleeves or pilasters as part of the block work rather than drilling into a finished wall. Combined fence and wall height limits vary by city and by HOA.
If you have a slope to hold back, a wall that is leaning, or a yard that needs a terrace to be usable, ask for a free site visit. We will measure the wall, look at where the water goes, tell you whether it needs an engineer, and send a written proposal within 48 hours.