A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable ADU Builders Across San Lorenzo
ADU construction in San Lorenzo typically runs $180,000 to $420,000 for a detached unit and $120,000 to $250,000 for a garage conversion, with permits taking four to seven months through Alameda County. Most of the work we do here hinges on one thing most homeowners never think about: what’s under the slab. San Lorenzo’s post-tensioned concrete foundations, poured everywhere from Via Arroyo to the streets off Bockman, can turn a routine plumbing trench into a five-figure repair if a cable gets severed. We scan before we cut. Every time. Call Russ Delmar and the Lodgewick team at (707) 760-0502 for a straight answer about your lot.
Why Lodgewick ADU San Francisco Is San Lorenzo’s Preferred ADU Builders Company
Homeowners across San Lorenzo keep our number saved for a reason: we write the price down before work starts, we show up when we say we will, and we put the 365-Day Done Right Promise in writing on every job. That means if something isn’t right, we come back and fix it within the year. No phone tag, no chasing a sub who vanished. Russ Delmar has steered every San Lorenzo project through Alameda County’s plan check and inspection process without a single stop-work order on a wind-load omission.
San Lorenzo’s housing stock is specific. Mid-century ranchers on flat, compact lots, many with original concrete slabs. That context changes how we frame, where we trench, and how we detail shear walls. A builder who mainly works Oakland infill or Hayward hillsides won’t have the same instincts. We coordinate from the San Francisco Bay Area office, but the crews who show up in San Lorenzo know precisely what a 1957 tract home off Paseo Grande needs.
We answer the phone with a live person, 24 hours a day. When a homeowner on Via Manzanas calls with a question about their permit status or an inspector’s note, they get Russ or a member of the crew who knows the project. Not a voicemail loop.
ADU Construction in San Lorenzo
ADU construction in San Lorenzo starts with what’s beneath the house. The majority of lots here sit on post-tensioned concrete slabs poured between the late 1940s and the mid-1960s. Those slabs contain high-tension steel cables under thousands of pounds of force. Cut one blind, and the slab can crack from edge to edge before framing even begins. That’s why a compliant San Lorenzo ADU quote includes X-ray or ground-penetrating radar scanning before any trenching for plumbing lines, a step that’s largely unnecessary in Oakland or Hayward where foundation types differ.
Permitting runs through Alameda County, which enforces wind-load calculations on all second-story ADUs. A detached unit behind a San Lorenzo rancher needs roof and wall ratings that hold under the county’s design wind speeds. We include those calculations in every permit package. A cheap quote often leaves them out, and the stop-work order arrives after trusses are already on order.
Foundation Scanning Before You Dig
Every garage conversion in San Lorenzo gets scanned before a saw touches concrete. We map cable locations, mark them, and route drain lines around them. If a cable sits exactly where the toilet flange needs to be, we use a side inlet or relocate the fixture rather than de-tension the slab.
Permit Packages That Pass the First Time
Alameda County plan check flags missing wind-load calcs, undersized shear wall nailing, and connector specs that don’t match the county’s details. We submit complete packages with the specific connectors named on the drawings. That’s how a San Lorenzo ADU gets approved without a second or third resubmittal cycle eating two months off your timeline.
Detached ADU in San Lorenzo
A detached ADU in San Lorenzo gives you a separate small house on your existing lot, and that’s exactly what a lodge is: a small house on a larger property. On the flat quarter-acre and fifth-acre parcels common here, a detached unit usually goes in the rear yard or takes the place of an aging detached garage. Budget $180,000 to $420,000 depending on whether you go site-built or prefab, with prefab units from companies like Abodu and Cover trimming two to four months off the construction schedule.
San Lorenzo’s setback requirements are strict on these small lots. A detached unit needs proper separation from the main house and side property lines, which pushes most designs toward a compact footprint with a second-story or loft configuration. That’s where wind-load detailing becomes non-negotiable. The county inspector will check every shear wall and connector on the final walkthrough.
Site-Built Versus Prefab on San Lorenzo Lots
Site-built detached ADUs work well when the lot has easy access for material deliveries and a foundation that’s already flat, which describes most of San Lorenzo. Prefab from Abodu or Cover makes sense when you want less time with a construction crew in your backyard. Either way, the same permit, the same wind-load calcs, and the same written guarantee apply.
Structural Connectors the Inspector Will Actually Check
Don’t let anyone tell you all hurricane ties are the same. Alameda County inspectors in San Lorenzo specifically look for Simpson H2.5A connectors on detached ADU roof-to-wall connections. Standard off-the-shelf H2 ties fail the structural inspection, and the fix means tearing out freshly installed shear wall nailing. We spec the right connector from day one and put it on the drawings.
Trusted Brands We Service in San Lorenzo
We install and finish ADUs from established prefab manufacturers and materials suppliers, and we stock the common parts San Lorenzo homes need: Simpson H2.5A connectors, James Hardie siding for the dry-summer stucco alternative, and Tuff Shed structures for detached studio conversions. When a Cover or Abodu unit arrives at a San Lorenzo lot, we handle the foundation, utility connections, and finish work under the same Kingswell Guarantee. You get one team accountable for the whole build, from the first scan of your slab to the final county sign-off.
Common ADU Builders Problems We See in San Lorenzo Homes
- Severed post-tensioned cables. A contractor cuts into a garage slab without X-ray scanning, hits a tensioned cable, and the slab cracks across the entire floor. The repair runs tens of thousands before any framing can start.
- Stop-work orders for missing wind-load calcs. Alameda County receives a permit package for a second-story ADU with no wind-load calculations. The roof trusses are already ordered. The county stops the job cold, and the homeowner waits months.
- Wrong shear wall connectors. Standard hurricane ties go in where Simpson H2.5A connectors are required. The structural inspection fails, the newly installed shear wall nailing gets torn out, and the budget blows past the original written quote.
- Drainage failures in wet winters. San Lorenzo gets real rain from November through March. An ADU sited without proper drainage and moisture management in the foundation detail will show water intrusion within the first season.
Pricing for ADU Builders in San Lorenzo, CA
A garage conversion in San Lorenzo runs $120,000 to $250,000. A detached ADU runs $180,000 to $420,000. Prefab units from Abodu or Cover typically land in the $180,000 to $300,000 range including site work, permits, and utility connections. What moves the number: whether your slab needs scanning and rerouting around post-tensioned cables, whether your lot triggers wind-load upgrades on a second story, and how much trenching the drainage plan requires. Every quote we give is written down before work starts. If the number changes, we tell you before the change happens. Call (707) 760-0502 to schedule a free estimate on your San Lorenzo property.
On a converted garage ADU off Via Arroyo, our crew hit a post-tensioned cable with a saw-cut before scanning. We called in ground-penetrating radar, mapped the cable grid, and rerouted the drain line with a side inlet to avoid de-tensioning the slab. The final inspection passed with the original foundation intact and the homeowner’s structural warranty preserved. That’s the difference between a builder who scans and one who guesses.
We Also Serve Cities Near San Lorenzo
Our ADU Builders team works throughout the East Bay. Beyond San Lorenzo, we regularly take on ADU projects in San Leandro, Oakland, Hayward, and Moraga. Each city has its own planning department quirks, and we know them all. If you’re just over the San Lorenzo line, call (707) 760-0502 and ask for Russ. If we can’t cross the boundary for a specific town, Russ will tell you straight and point you to someone who can. We serve San Lorenzo and its neighbors with the same written guarantee.
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 ADU Builders in San Lorenzo
San Lorenzo does not mandate X-ray scanning by ordinance, but cutting a post-tensioned slab without scanning is the single costliest mistake you can make on a garage conversion here. The concrete slabs under most 1940s to 1960s tract homes contain tensioned steel cables. Sever one, and the slab can crack across its full span, requiring a structural repair before any plumbing or framing work proceeds. We scan every slab with ground-penetrating radar before a saw blade touches concrete, and that scan is included in our written quote. Call (707) 760-0502 to have your slab checked before work begins.
Detached ADU roofs in San Lorenzo must meet Alameda County’s design wind speed requirements, which for this area typically correspond to approximately 85 mph exposure category C or D depending on the exact site conditions and roof height. The specific rating your structure needs depends on your lot’s exposure and the ADU’s roof geometry. What matters most is that the calculations appear in your permit package and the specified connectors, Simpson H2.5A among them, match what’s installed. Call (707) 760-0502 for a written quote that includes the correct wind-load package for your lot.
Documented wind-load compliance gives your insurer proof that your ADU was built to withstand the storm forces it already agreed to cover. If a winter storm damages your ADU roof, the adjuster can verify from your permit file that the structural design met code. That documentation supports your claim and can influence your premium at renewal, since a verified structure presents lower risk than one with unknown construction details. We keep every wind-load calculation, inspection record, and connector spec on file for the projects we build in San Lorenzo. Call (707) 760-0502 to build a unit with a paperwork trail that’s complete.
Over-garage ADUs are generally allowed on San Lorenzo lots, but whether yours will pencil out depends on the existing garage foundation and roof truss conditions. Many mid-century garages in San Lorenzo were built as lightly framed structures never intended to carry a second-story living space. That means the existing slab and walls may need significant structural upgrades before a JADU or full second-story ADU goes on top. We assess the foundation, run the truss calculations, and give you a written number before work starts. Call Russ at (707) 760-0502 for an honest evaluation of your garage’s potential.
San Lorenzo’s Title 24 energy requirements for ADUs are standard for the California coastal climate zone: insulated walls and ceiling assemblies, low-e windows, a high-efficiency heat pump or mini-split system, and water heating that meets current efficiency standards. The mild Mediterranean climate means you don’t need extreme insulation packages or heavy HVAC sizing, but you do need proper drainage and moisture management for the wet winter months. We include all required Title 24 documentation in your permit package and verify compliance during the final inspection. Call (707) 760-0502 for a quote that covers every energy item the county will check.
Ready to Build Your ADU in San Lorenzo?
You want a real number, in writing, before anyone swings a hammer on your San Lorenzo property. You want a builder who knows post-tensioned slabs, Alameda County wind-load details, and the specific connectors the inspector will check by name. Russ Delmar and the ADU Builders team at Lodgewick ADU San Francisco deliver all of it under the 365-Day Done Right Promise, written on every job. Call (707) 760-0502 for your free estimate, and we’ll walk your lot, scan your slab, and give you a written price before you commit to anything.
Written by Russ Delmar, Owner at Lodgewick ADU San Francisco, serving San Lorenzo and the surrounding East Bay.
