Retaining wall contractor, Peninsula & South Bay

Our seven published wall scopes run from $4,500 for a wall and steps up to $97,500 for a tiered hillside program with steps and pillars, and larger programs go beyond that. Walls are built as part of an integrated landscape project at our $25,000 project minimum. We do not publish a per-square-foot wall rate, because on the projects we can actually measure it does not predict the cost: excavation, access, soil export, drainage and engineering move the number far more than the wall face does.

Wall-face square footage is generally wall length multiplied by visible wall height. It is useful for a first comparison and it is incomplete, because it counts nothing below or behind the face. On our Hillsborough project about 180 linear feet of tiered wall at three feet high is 540 square feet of face, and the wall, steps and pillars line was $85,500 to $97,500, or $158 to $181 per square foot of visible face. That line also carried a stair-wall run, two capped pillars and demolition of the previous wall and its footing.

Possibly. California Building Code Section 105.2 exempts from building permit retaining walls not over 4 feet in height, measured from the bottom of the footing to the top of the wall, unless supporting a surcharge or impounding Class I, II or IIIA liquids. That is a building-permit exemption, not a universal no-permit rule: planning, grading, drainage, property-line and local requirements can still apply. Cities also amend the code locally. The city or county with jurisdiction makes the final determination for your property.

A surcharge is an additional load on the soil the wall is retaining. A driveway, parked vehicles, a structure, a pool, a steep backslope or stored material near or above the wall can all be surcharges. It matters because a surcharge can change the wall system, the reinforcement and whether the wall is exempt from permit at all, even when the visible wall looks low.

There is no universal answer. It depends on the jurisdiction, the total height, the wall system, surcharge, soil, slope and nearby improvements. CMHA recommends an engineered design by a registered professional for segmental walls over four feet. Complex or higher-risk walls should be evaluated by the appropriate design professional, and we are not that professional: we name who is.

No. A conventional segmental wall is a gravity structure that resists the soil through the self-weight of the units, and it has no geogrid at all. Reinforced segmental systems use horizontal geosynthetic reinforcement extending into properly placed and compacted reinforced fill, where the approved wall design requires it. Anyone telling you every wall needs geogrid is describing one system and calling it all of them.

No. Water always has to be addressed, but the components vary by system and site. A design may use drainage aggregate, filter material, perforated pipe, a defined outlet, weep openings or a combination. Some segmental systems drain through aggregate and a toe drain with no face weep holes at all, and adding weep holes to a wall that was not designed for them is not an improvement.

There is no single cause. Inadequate design, poor foundation conditions, uncontrolled water, unsuitable backfill, insufficient reinforcement, poor compaction, erosion, a surcharge nobody accounted for, global slope movement, or construction that did not match the design can all do it, often in combination. Proper water management reduces the risk of damaging water pressure, erosion and saturated backfill. It does not eliminate it.

Sometimes, but rebuilding the visible face without correcting what caused the movement is unlikely to give a durable result. A leaning wall is usually reporting a problem behind it. Sequoia evaluates failing walls as part of qualifying replacement, terracing or integrated landscape projects. We do not provide small cosmetic patches or standalone minor wall repairs.

Not necessarily. When an upper and a lower wall are close enough together they can behave as one system, and the setback between them becomes a structural question rather than an aesthetic one. Tiered geometry should be evaluated as part of the complete design, not treated as a way to avoid engineering.

There is no best. Conventional segmental, reinforced segmental and reinforced CMU are different structural systems, not three finishes at one price, and the right one depends on height, soil, drainage, the space available behind the wall, access and how it needs to look. Stone on our walls is a veneer over a structural core, and the core is what holds the hill up.

Design, engineering and approvals can take several weeks or longer depending on the jurisdiction and the complexity. Active construction can range from several days for a qualifying low-wall scope to multiple weeks for engineered, tiered or access-constrained work. The project-specific schedule begins once the required approvals and material conditions are known, and we do not quote a build duration before that.

No. Sequoia focuses on qualifying replacement, terracing and integrated landscape projects, with a $25,000 project minimum. If you need a small patch or a standalone minor repair, we are not the right company and we will say so in the first conversation.

Yes, on every retaining-wall project. Foundation preparation, drainage and reinforcement are photographed before they are covered and the record goes in your project portal. It is the only way anyone can verify what is behind a finished wall once the face is on.

$25,000. A retaining wall is almost always built together with the terracing, steps, drainage, paving and planting around it rather than on its own.