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 Leandro
ADU construction in San Leandro usually costs between $180,000 and $420,000 for a detached unit, with prefab installations landing closer to $120,000 – $220,000. We’re Lodgewick ADU San Francisco, and we’ve spent years working with homeowners in Estudillo Estates, Bancroft Avenue, and the neighborhoods east of East 14th Street. If you’re weighing a detached ADU, a garage conversion, or a prefab install, call us at (707) 760-0502 and we’ll give you a written price before any work starts.
Why Lodgewick ADU San Francisco Is San Leandro’s Preferred ADU Builders Company
San Leandro homeowners call us because we show up when we say we will and we put every commitment in writing. Our crew knows this city’s housing stock: the 1940s – 70s ranch and split-level homes with wide lots north of Highway 238, the older sewer laterals east of East 14th Street, and the clay soil that behaves differently here than in neighboring Oakland or Moraga. That local knowledge means we don’t get surprised mid-build, and neither do you.
Every project runs under The Kingswell Guarantee. That means a written price before we start, a defined arrival window, a clean job site every day, and a written guarantee on the finished ADU. If something isn’t right within 365 days, we come back and fix it. No phone tag, no chasing a subcontractor. A live person answers our phone 24/7, which matters when you have a question about your permit or your foundation inspection at 8 p.m.
Russ Delmar leads our San Leandro work. He’s walked dozens of these lots, from Washington Manor to Broadmoor, and he’ll tell you straight what your property will support before you spend a dollar. That’s the way we’ve done it since 2010, and it’s why homeowners here trust us with projects their neighbors recommended us for.
ADU Construction in San Leandro
ADU construction in San Leandro means building a second, fully independent living unit on a lot you already own – a small house with its own kitchen, bathroom, entrance, and address. On the flat 1950s – 70s single-family lots common here, that usually means either converting an attached garage or building a new detached structure in the backyard. Homeowners pursue this when a parent needs to live close by, when adult children can’t afford Bay Area rents, or when rental income from a studio unit makes the mortgage work.
What a compliant quote includes
A real San Leandro ADU quote accounts for the city’s sewer lateral ordinance east of East 14th Street. Many of those laterals are original clay pipe from before 1970, and roots from mature liquidambar trees along the street have invaded them over decades. If a video inspection shows root intrusion, the City of San Leandro will require lateral replacement before you can get your foundation permit. A responsible quote includes that inspection up front, plus the $5,000 – $10,000 replacement if it’s needed. A cheap quote skips it and lets the city stop your build later.
Permits and inspections
San Leandro requires building permits, a soils report for detached structures, and compliance with California’s Title 24 energy code. Our team handles the permit application, coordinates the sewer lateral inspection, and schedules every city inspection through final sign-off. You’ll know the permit status from us, not from wondering.
Detached ADU in San Leandro
A detached ADU in San Leandro is a standalone structure in your backyard, typically 400 – 1,200 square feet, with running water, power, a kitchen, and a bath. It is the most common ADU type we build here because San Leandro’s lots are wide enough to hold one without sacrificing the whole yard. A typical detached ADU runs $180,000 – $420,000 depending on size, foundation work, and finishes.
Foundation work on clay soil
San Leandro’s native clay expands when wet and contracts when dry. A standard slab poured without accounting for that movement will crack during the first rainy season. We specify deep pier or post-tension foundations where the soils report calls for them, which most lots east of East 14th Street do. That foundation work adds cost up front and prevents structural problems later.
Drainage and moisture management
Cool, fog-influenced summers and rainy winters mean your ADU envelope has to handle moisture from both directions. We use James Hardie fiber-cement siding assemblies rated for wind and moisture exposure, with proper rainscreen details. Passive solar design – orienting the main glazing south and shading it properly – keeps the unit comfortable without air conditioning, which matters in a climate like ours.
Trusted Brands We Service in San Leandro
We install and finish ADUs from Abodu, Cover, Tuff Shed, and James Hardie, and we stock common components locally so San Leandro projects don’t stall waiting on parts from Southern California. Russ Delmar has hands-on familiarity with each system’s foundation requirements and shear-wall details, which matters when your lot’s soils report calls for pier support instead of a standard slab. If you’re comparing a prefab Abodu unit against a site-built structure, we’ll walk you through the real cost differences for your specific lot – including the sewer lateral and clay soil work that applies here, not in a generic brochure.
Common ADU Builders Problems We See in San Leandro Homes
- Root intrusion in pre-1970s sewer laterals. East of East 14th Street, most original laterals are clay pipe that mature street trees have invaded. We video-inspect every lateral before foundation work. If roots are present, the city requires replacement before the build continues.
- Clay soil cracking standard slabs. San Leandro’s expansive native clay moves seasonally, unlike the sandy loam found in parts of Oakland. Homeowners who skip a proper soils report end up with a cracked foundation after the first winter. We spec deep piers where the report calls for them.
- Wind-shear failures on prefab wall panels. Some off-the-shelf prefab systems don’t meet local wind-load requirements without re-engineering. We verify every panel system against San Leandro’s specific shear-wall code before it ever reaches your lot.
- Electrical and plumbing upgrades on 1940s – 70s homes. Original panels and waste lines in San Leandro’s ranch and split-level stock often can’t handle a second dwelling’s load. We include panel and line upgrades in the written quote, so the number you see covers the whole job.
Pricing for ADU Builders in San Leandro, CA
Here are real numbers for San Leandro’s market. A prefab studio ADU from Abodu or Tuff Shed typically runs $120,000 – $220,000 including site work and utility connections. A site-built detached ADU of 600 – 800 square feet usually costs $220,000 – $340,000. A larger two-bedroom detached unit with a full kitchen runs $340,000 – $420,000, not counting sewer lateral replacement if your lot east of East 14th Street requires it. What moves the price: foundation type, lateral condition, panel upgrades, finishes, and whether you choose prefab or site-built. We write the price down before any work begins, and that number does not change at the door. Call (707) 760-0502 for your exact quote.
We Also Serve Cities Near San Leandro
While this page is for San Leandro homeowners, our ADU Builders team also serves San Lorenzo, Oakland, Moraga, and Emeryville. Each city has its own permit office and soil conditions, but the same written-price guarantee applies in every one of them. If you’re just over the border, ADU Builders in San Leandro can tell you whether your property falls in our service area.
Serving San Leandro, CA - Our Local Coverage Area
We’re based in the San Leandro 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 Leandro
The old sewer lateral can stop your foundation permit cold. East of East 14th Street, many San Leandro homes have original clay laterals from before 1970 that have been infiltrated by roots from mature liquidambar street trees. The City of San Leandro requires a video inspection before foundation work; if roots are found, you must replace the lateral, typically $5,000 – $10,000, before the build can continue. Call (707) 760-0502 and we’ll schedule the inspection as part of your written quote.
San Leandro’s wind exposure near the Bay and winter rain require a weather-resistant barrier and siding rated for moisture, plus shear-wall engineering that meets current code. We specify James Hardie fiber-cement assemblies with proper rainscreen details on every detached ADU. The city inspector verifies the shear-wall nailing pattern and the weather barrier before insulation goes in.
San Leandro’s native clay expands when wet and contracts when dry, which cracks a standard slab within a season or two. A soils report determines whether your lot needs deep piers or post-tension design. Most lots east of East 14th Street do. It adds cost up front and prevents structural problems that would cost far more later.
Yes, but only after a local engineer verifies the panel system meets San Leandro’s wind-load and shear-wall requirements. Not every off-the-shelf system does without re-engineering. We work with Abodu, Cover, and Tuff Shed and handle that verification for you. Call (707) 760-0502 to find out which systems pass locally and what your all-in cost would be.
Documented compliance from your permit records and final inspections proves the structure met code when the ADU was built. That matters in a claim. If wind or water damage occurs later, the insurer will check whether the structure was built to the standard in effect at the time. Our written guarantee includes the full permit and inspection record for your file.
Written by Russ Delmar, Owner at Lodgewick ADU San Francisco, serving San Leandro since 2010.
