
Get a steel-reinforced concrete block foundation wall sized for your lot, built for Marin County's wet winters and seismic zone - with permits handled for you from start to finish.

Foundation block wall installation in Larkspur means building a structural wall from reinforced concrete masonry units - used to create residential foundations, support additions and ADUs, and retain hillside soil below a structure, most residential projects taking three days to two weeks once permits are approved and footings are set.
Most Larkspur homeowners reach us because they are adding living space - an ADU, a garage, a basement room - and the project needs a new structural foundation wall to match. Others come to us because an older wall is cracking or bowing and a repair is no longer enough. Concrete block is the standard material for this work because it handles the hillside terrain and wet winters that define Marin County properties better than most alternatives.
If you already know you also need a full foundation repair on an existing structure, that assessment happens at the same site visit - so you will leave with a clear picture of what needs to be built new and what can be fixed.
If you see cracks running at an angle - especially ones wider than a pencil line - the wall is moving or settling unevenly. In Larkspur's hillside neighborhoods, soil movement after heavy winter rains is a common trigger for this kind of cracking. A crack that was small last year and is noticeably wider this year needs professional attention right away.
Stand back and look at your foundation or retaining wall from a distance. If any section curves or leans toward the house rather than standing straight, soil pressure is winning. This is especially common in Larkspur homes where clay soils have been saturated by several wet winters in a row. A bowing wall is a structural problem, not a cosmetic one.
Damp spots, white chalky deposits, or actual water coming through your foundation wall after a storm means the waterproofing has failed. Larkspur's heavy winter rainfall makes this problem show up fast and worsen quickly. Left unaddressed, water intrusion damages everything in your crawl space or basement and eventually compromises the wall itself.
If you are planning any addition to your home - including an accessory dwelling unit, which is increasingly common in Marin County - you will almost certainly need new foundation block wall work to support it. This is a planned project rather than an emergency repair, but it still requires a licensed masonry contractor and a building permit before any work begins.
We build and replace foundation block walls for residential additions, ADUs, garage foundations, and hillside retaining structures. Every project starts with a proper footing - the concrete base the wall sits on - and includes steel reinforcement inside each block core, filled with concrete to meet California's earthquake requirements. For any wall that holds back soil or sits below grade, we install a drainage layer and waterproofing membrane before backfilling, which is the step that protects the wall from Marin County's heavy seasonal rain.
If you also want an outdoor kitchen or another permanent masonry structure added to the property at the same time, we can assess and plan both during the same site visit to keep your project on one schedule. For existing foundation issues on an older Larkspur home, our foundation repair service covers crack repair, wall stabilization, and seismic reinforcement of walls that do not need full replacement.
Best for homeowners building an addition, ADU, or detached garage that needs a full perimeter foundation wall built to current code.
Suits homeowners with an older block wall that is beyond repair - bowing, heavily cracked, or lacking seismic reinforcement - where a full rebuild is the safer long-term choice.
Ideal for hillside Larkspur lots where a structural wall needs to hold back soil at the base of a home and tie into the existing foundation system.
Right for homeowners whose older block walls lack the steel and filled-concrete cores now required in the Bay Area seismic zone - where the upgrade improves safety without a full wall replacement.
Larkspur sits in one of the most seismically active parts of the country, and the building code here reflects that. Every masonry foundation wall in this area must include steel reinforcing rods through the hollow block cores, filled with concrete - far more reinforcement than most other states require. On top of that, much of Larkspur is on hillside terrain with clay-heavy soils that hold rainwater rather than drain it. During wet winters, that saturated clay puts enormous lateral pressure against any below-grade wall. Getting the drainage design right is not optional - it is what separates a wall that stands for 50 years from one that starts to bow after the first five. We serve homeowners throughout San Rafael and Mill Valley who face the same hillside terrain and soil conditions.
Larkspur also has a substantial share of homes built between the 1940s and 1970s. Many of those original foundations were built to standards that predate modern earthquake safety requirements - which means a fair number of homeowners here are looking at walls that need reinforcement or replacement, not just patching. The Town of Larkspur Building Division requires a permit and inspection for this work, and turnaround times can run from a few weeks to longer depending on project complexity. If you want foundation work completed before the November rainy season, the permit process should start no later than August. We handle that paperwork as part of every project, so you are not navigating the process alone.
We respond within one business day. We will ask a few basic questions about the wall size, location, and any visible problems so we can prepare for the site visit. No price quotes over the phone - foundation work varies too much from property to property.
We visit your property to assess the slope, soil, and any existing structures. We apply for the building permit on your behalf - this is standard for legitimate contractors in Larkspur. Permit approval typically takes two to four weeks, so factor that into your timeline.
Once permits are approved, the crew excavates the area and pours the concrete footing - the base the wall sits on. Expect some disruption to your yard during this phase. Clear the work area of furniture, plants, and stored items before the crew arrives.
The crew lays blocks row by row with steel rods inside the cores, fills the cores with concrete, then applies waterproofing and installs drainage before backfilling. The Town of Larkspur inspects the work at key stages. Once the inspector signs off, we clean up and walk you through the finished wall.
We visit every site in person before giving a price - no remote estimates, no surprises once work begins. Reach out today and we will respond within one business day.
(415) 390-3464Every block wall we build in the Bay Area includes the steel reinforcement and filled concrete cores that California requires for seismic zone construction. We do not offer a cheaper option without the reinforcement - it is not legal here, and it would not protect your home.
We have worked on hillside Larkspur lots with the sloped terrain, limited equipment access, and clay soils that make this area different from flat-ground construction. That experience shapes how we design footings, manage drainage, and plan excavation on every project.
We handle the building permit application and manage the Town of Larkspur inspection process on every foundation project we take on. Unpermitted foundation work creates problems when you sell or refinance - we make sure that never becomes your issue. You can verify our California contractor license on the CSLB website before you call.
We give you a detailed written estimate before we touch anything, and we walk you through every line item in plain language. The price we quote after a site visit is the price you pay - foundation work has too many variables for a phone number to mean anything.
These are the things that matter most when you are trusting someone to work on your home's foundation. We take each one seriously because we work in the same community and our reputation is built one project at a time. The National Concrete Masonry Association sets the technical standards we follow for block wall construction across every project.
Permanent masonry outdoor kitchen structures built on a proper concrete footing - grill surrounds, countertops, and pizza oven bases designed for Larkspur's climate.
Learn MoreCrack repair, wall stabilization, and seismic reinforcement for existing Larkspur foundations that need work without a full block wall replacement.
Learn MoreMarin County's rainy season starts in November - contact us now to get permitted and scheduled before the first storm hits your property.