A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Garage Conversion Contractor Across San Lorenzo
If you own a mid-century ranch home in San Lorenzo, you’re probably sitting on more square footage than you realize. That attached garage with the roll-up door eating half your lot? It’s a one-bedroom ADU waiting to happen, and it’s likely the fastest path to rental income or a quiet guest suite you’ll ever build. Converting a garage in San Lorenzo comes with real complications though – post-tensioned slabs, 1940s-era wiring, strict setback rules – and getting them wrong means stop-work orders and blown budgets. We’ve worked through every one of these surprises in San Lorenzo homes, and we put the inspection findings, the allowances, and the full price in writing before the first cut. Call us at (707) 760-0502 for a free estimate, and we’ll walk your specific garage with you.
This page explains exactly how we handle the hidden code and structural surprises unique to converting a San Lorenzo mid-century garage – especially post-tensioned slab cutting and 1940s-era wiring – so the quote you approve is the budget you actually pay.
Why Lodgewick ADU San Francisco Is San Lorenzo’s Preferred Garage Conversion Contractor Company
We’ve spent a lot of time inside San Lorenzo’s original ranch homes, and that matters more here than in most East Bay cities. The homes on Via Nube, Via Manzanas, and Paseo Grande were largely built the same way between the 1940s and 1960s: single story, slab-on-grade, wood frame, and attached garages that were never meant to hold a bedroom. Garage Conversion Contractor work in San Lorenzo means knowing what’s behind those walls before you quote a number – and we do.
Lodgewick ADU Builders is the ADU company of the Kingswell family, established in 2010. Every San Lorenzo project runs under The Kingswell Guarantee: a written price before work begins, a defined arrival window, a clean job site, and a written guarantee on every job. If something isn’t right within 365 days, we come back and make it right – free. That’s not a marketing line; it’s printed on the contract you sign before we ever pull a permit.
Our owner, Russ Delmar, runs every San Lorenzo estimate personally. He’s walked enough of these slabs to know that a “simple” garage conversion on Bockman Road is rarely simple once you open the walls. That’s why our estimates include line-item allowances for the code upgrades Alameda County requires – not a vague “we’ll figure it out later” that turns into a $40,000 surprise. When you call, a live person answers. Not a voicemail, not a chatbot. That’s true at 2 p.m. and at 2 a.m.
We serve San Lorenzo locally, with dispatch and scheduling coordinated from the brand’s San Francisco Bay Area office. Our uniformed, background-checked technicians are familiar with the subdivision layouts, the county inspection schedule, and the specific soils and drainage patterns across the unincorporated community. That local knowledge means fewer surprises and a smoother permit process for you.
Garage Apartment Conversion in San Lorenzo
A Garage Apartment Conversion in San Lorenzo typically turns an attached or detached garage into a self-contained rental unit with its own kitchen, bath, and private entrance, and on the flat, small lots that define this community, it’s often the only way to add an ADU without sacrificing yard space. Most San Lorenzo ranch homes sit on lots between 5,000 and 6,500 square feet, so building out means losing usable outdoor space – converting the garage you already have means you keep the backyard and still add 350 to 500 square feet of living space.
In San Lorenzo, a garage apartment conversion generally runs $145,000 to $220,000 for a 400-square-foot attached garage, depending on whether you need foundation improvements, a new subpanel, or full seismic upgrades. Detached conversions run higher, usually $165,000 to $250,000, because they require running new utilities across the yard and often need a new roof structure. These are real numbers for this market, not national averages.
Attached Garage Conversion
Most San Lorenzo garages are attached, sharing one wall with the house. That’s actually helpful for cost – plumbing and electrical runs are shorter, and the roof framing is already tied in. The tradeoff is that the shared wall often hides the original cloth-wrapped wiring and undersized framing we’ve come to expect in 1940s and 1950s construction.
Detached Garage Conversion
Detached garages on San Lorenzo lots give you more design freedom and better sound separation from the main house, but they cost more because the slab wasn’t poured with living space in mind. Most need new floor insulation, a separate sewer lateral, and often a new roof. We handle every piece of that, including the trenching from the house to the structure.
Garage Conversion Permit in San Lorenzo
A Garage Conversion Permit in San Lorenzo goes through Alameda County’s building department, since San Lorenzo is an unincorporated community with no city hall to file at, and the permit process here triggers code upgrades that most homeowners don’t see coming when they first price the job. San Lorenzo sits in unincorporated Alameda County, which means your plans go to the county’s Community Development Agency in Hayward, not a local San Lorenzo office. The county enforces current California Residential Code, including Title 24 energy standards and the California Green Building Standards Code.
What does a permit actually cost? Plan check and permit fees for a typical 400-square-foot garage conversion in San Lorenzo run $6,000 to $11,000, depending on the review path and whether you need structural calculations. That’s on top of construction costs. We include permit management in our scope – we draw the plans, submit them, respond to plan-check comments, and pull the permit. You won’t shuttle paperwork between San Lorenzo and Hayward; that’s our job.
What the County Checks
Alameda County plan reviewers focus on structural loads, egress windows, smoke and carbon monoxide alarms, insulation values, and the connection between the existing house and the new ADU. If the garage was built with a shallow perimeter footing – common in San Lorenzo’s original construction – the reviewer often requires an engineered retrofit before you can load a bedroom wall onto it. We identify this during our pre-bid inspection so it’s in your written price from day one.
Inspection Sequence
Once excavation or slab work starts, expect inspections at rough-in for plumbing and electrical, then framing, insulation, and a final. San Lorenzo jobs often trigger a soils inspection if we’re adding any new footing or grade beam. We schedule and attend every inspection, and we don’t cover up any work until the county signs off. That’s the only way to keep a San Lorenzo conversion from turning into a rework nightmare.
Trusted Brands We Service in San Lorenzo
Lodgewick works hands-on with established ADU brands and materials matched to your San Lorenzo lot, budget, and timeline. We have direct experience with Abodu and Plant Prefab for prefabricated ADU shells that can reduce on-site framing time by weeks, plus James Hardie siding for exteriors that stand up to our wet winters and dry summers without warping or rot. If you want a Tuff Shed structure converted into a finished living space, we do that too. We maintain local parts accounts and material relationships that keep San Lorenzo jobs moving – not waiting on a shipment from out of state.
Common Garage Conversion Contractor Problems We See in San Lorenzo Homes
- Post-tensioned slab strikes: San Lorenzo homes built between 1950 and 1965 often have concrete slabs with steel cables running through them under tension. Cutting blindly into the slab to trench for plumbing can sever a cable, causing structural damage and an immediate county stop-work order. X-ray scanning before cutting is almost always required here.
- Cloth-wrapped wiring from the original build: Original 1940s and 1950s garages in San Lorenzo frequently still carry the original cloth-insulated wiring, which fails current code once the space becomes habitable. A new subpanel and dedicated circuits are a standard part of every conversion we quote.
- Undersized garage door framing: The opening where the roll-up door sat was never designed to hold a wall with a window and an exterior door. Most San Lorenzo garages need an engineered header and new king studs before we can close up that opening, and the county plan reviewer will ask for the calculations.
- Drainage around the slab edge: San Lorenzo’s heavy winter rains pool against slab edges on flat lots, especially in the neighborhoods west of Hesperian Boulevard. Converting a garage to living space means adding surface drainage, and often a French drain along the new entry, to keep water out of the finished floor.
We recently converted a 1950s attached garage on Via Nube into a one-bedroom ADU. When our tech opened up the wall shared with the house, we found original cloth-wrapped wiring that didn’t meet current code and undersized 2×4 framing around the garage door opening. We stopped work, walked the homeowner through the written change order for a new subpanel and engineered header, got sign-off, and completed the rough-in inspection the following week. That’s how it works on a San Lorenzo slab – you don’t guess, you scan, you document, and you get written approval before any change moves forward.
Pricing for Garage Conversion Contractor in San Lorenzo, CA
Here are real San Lorenzo numbers for 2026. A standard attached one-car garage conversion (roughly 250 to 320 square feet) runs $120,000 to $175,000. A two-car attached garage converted into a one-bedroom ADU runs $175,000 to $240,000. Detached garage conversions start around $165,000 and can reach $280,000 for a fully detached unit with a new roof, separate utilities, and site work. These figures include permit fees, engineering, and the code upgrades San Lorenzo’s housing stock almost always triggers.
What moves the price: whether your slab needs X-ray scanning and trenching (most do), whether the original footing carries the new wall load, whether you need a panel upgrade, and how far the county makes you push setbacks based on your specific lot lines. We put every known variable into the written estimate. If we open a wall and find something we couldn’t have seen, we price the change in writing and you approve it before we proceed – never the other way around. Call (707) 760-0502 for a free estimate on your San Lorenzo garage.
We Also Serve Cities Near San Lorenzo
Our Garage Conversion Contractor in San Lorenzo service area extends to the surrounding East Bay communities. We regularly work in San Leandro, Oakland, Hayward, and Moraga. Each city has its own code path and housing stock quirks, but the same written-pricing rule applies everywhere: you see the number before we start, and it doesn’t change without your signature.
Serving San Lorenzo, CA - Our Local Coverage Area
We’re based in the San Lorenzo area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About Garage Conversion Contractor in San Lorenzo
No, but most do. If your San Lorenzo home was built between 1950 and the mid-1960s and the original garage slab is still in place, there’s a strong chance it contains post-tensioned cables that can’t be cut safely without scanning. We bring in a concrete scanning contractor before any trenching starts on every slab we can’t verify through original plans. The scan costs $800 to $1,500 and tells us exactly where we can and can’t cut. Skipping it risks a snapped cable, structural damage, and a county stop-work order that will cost far more than the scan. Call (707) 760-0502 and we’ll tell you whether your particular slab is a scanning candidate.
Opening the walls means the county can require you to bring everything we expose up to current code – electrical, insulation, and framing. In most San Lorenzo garages, that means replacing cloth-wrapped wiring with modern Romex, adding a new subpanel if the existing one is undersized, and reinforcing the garage door opening with an engineered header. You may also need a hardwired smoke and carbon monoxide system tied to the main house. We write these upgrades into the original estimate as allowances so they don’t ambush you mid-project.
Often, yes. Many original San Lorenzo garage slabs have a thickened edge meant to hold a garage door, not a fully loaded exterior wall with a bed and occupants inside. The county plan reviewer will ask for engineering that confirms the existing footing can carry the new loads, and in many cases we add an interior grade beam or pier supports to satisfy that requirement. We include the structural evaluation in our estimate, so if your footing needs work, you’ll know it before permits are pulled. Call us for a free site walk and we’ll be specific about your garage.
Because San Lorenzo lots are small and homes were built close to property lines, the existing garage often already sits at or near the setback limit. For an attached conversion, the county typically allows you to keep the existing footprint, but any new exterior stair, entry landing, or utility pad may need to stay within the established building envelope. We check your lot’s exact setbacks against county records before designing the conversion, so you don’t get a plan rejection after paying for drawings.
Sometimes, yes. If the design allows us to run plumbing along the exterior wall or through an existing plumbing wall shared with the house, we can often avoid cutting the post-tensioned slab entirely. We may route water and drain lines through the existing bathroom wall or build a raised platform for the new wet area. Where trenching can’t be avoided, we X-ray first and cut only in the clear zones between cables. This is the correct and safe approach for San Lorenzo’s slab homes, and it’s the only approach we use.
Written by Russ Delmar, Owner at Lodgewick ADU San Francisco, serving San Lorenzo with written pricing and the 365-Day Done Right Promise on every garage conversion.
Ready to see what your San Lorenzo garage can become? Call (707) 760-0502 now for a free, no-pressure estimate. A live person answers, and we’ll schedule a walk-through of your garage and lot at a time that works for you. The price goes in writing before anything else happens.
