A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Home Addition Contractor Across Burlingame
A home addition in Burlingame typically costs $180,000 to $450,000 depending on whether you’re converting a detached garage, adding a second story, or bumping out a kitchen. Most projects take 5 to 10 months from design review to final inspection, with garage conversions running faster than ground-up additions. That’s the honest range before anyone picks up a hammer. Call (424) 328-5746 and we’ll put a written price in front of you before any work starts.
We know Burlingame’s streets, its building department, and its older homes. Our crews work in Easton Addition, Lyon-Hoag, and the flats near Broadway on a regular basis. When you call, a live person answers. When we walk your lot, we’re already thinking about setbacks, seismic straps, and whether your detached garage can legally become an ADU under Burlingame’s current zoning. That local knowledge changes the estimate you get, and it changes how smoothly the job runs.
Why Benson ADU San Francisco Is Burlingame’s Preferred Home Addition Contractor Company
Benson ADU San Francisco operates as part of the Relay Home Co. family, founded in 2006. The brand is built on one thing: written transparency. Every Burlingame project gets a written price before work begins, a 365-Day Done Right Promise, and a written guarantee stamped on the contract. If something isn’t right within a year, we make it right. That’s not marketing language. It’s the deal.
Our technicians arrive in uniform, background-checked, and ready to explain what they’re doing in plain English. Burlingame homeowners tell us the biggest difference between us and the last contractor they called is that we name prices out loud and stick to them. No verbal estimate that drifts by forty grand after demo starts. No phone tag. Our Home Addition Contractor team handles everything from first site visit to final walkthrough.
We’re authorized to build with leading prefab brands including Abodu, Cover, and Tuff Shed, plus James Hardie cladding for site-built additions. That gives Burlingame homeowners options: a panelized ADU from Abodu, a Tuff Shed shell we finish out, or a fully custom site-built addition with Hardie siding. You can research every brand we offer before you ever sign anything.
Garage Addition Contractors in Burlingame
Garage Addition Contractors in Burlingame spend most of their time on conversions of pre-1940 detached garages, especially in the Easton Addition and Lyon-Hoag neighborhoods. These garages were built for Model T Fords, not living space. A typical conversion runs $120,000 to $220,000 and involves structural reinforcement, excavation for ceiling height, moisture management, and full electrical and plumbing rough-in, plus design review approval from the city. When a Burlingame homeowner wants rental income or space for an aging parent without building new from scratch, the detached garage is usually the smartest asset on the lot.
Seismic and Foundation Work Comes First
Most Burlingame garages from the 1920s and 1930s sit on unreinforced masonry or thin perimeter footings. Before any framing happens, those foundations need seismic retrofitting, which can add $25,000 to $45,000 to the total. We inspect this on the first site visit so the number we give you includes it. No surprises in week six.
Excavation and Water Table Management
Getting 7 feet 6 inches of ceiling height often means digging down, and Burlingame’s water table sits high. We install moisture barriers, perimeter drains, and crawlspace ventilation as standard on these jobs. Skip any of that and you’ll be chasing mold in two years.
Bathroom Addition Contractor in Burlingame
A Bathroom Addition Contractor in Burlingame typically adds a full bath for $55,000 to $110,000 depending on whether plumbing stacks are nearby, whether the home is on a crawlspace or slab, and whether the addition triggers design review. Older Burlingame homes often have one bathroom for three bedrooms, and adding a second bath inside an existing footprint or as a small bump-out is one of the highest-ROI projects a homeowner can do. It also changes how a family actually lives in the house: no more morning traffic jams at the single bathroom door.
Working With Old Plumbing and Tight Spaces
Burlingame’s early 20th-century homes have cast iron waste lines and galvanized supply pipes that are often at the end of their service life. We replace what’s needed, cap what isn’t, and route new PEX and ABS through existing walls whenever possible. A good bathroom addition is one that doesn’t require gutting the living room to get the pipes where they need to go.
Stealthy Bathroom Additions That Pass Design Review
In historic neighborhoods, the city wants additions that look like they’ve always been there. We match rooflines, stucco texture, and window proportions to the original structure. That matters in Burlingame, where design review can stall a project for months if the plans look out of character.
Trusted Brands We Service in Burlingame
We build with brands Burlingame homeowners can verify independently. Abodu and Cover provide panelized ADUs engineered for California seismic zones. Tuff Shed gives us a weather-tight shell we finish into a conditioned space. James Hardie fiber cement siding handles Burlingame’s foggy mornings without rotting, warping, or attracting termites the way wood does near the bay. We stock materials locally and stage deliveries to Burlingame jobsites so crews aren’t waiting on supply-chain delays. When you pick a brand, we put it in writing and it shows up on schedule.
Common Home Addition Contractor Problems We See in Burlingame Homes
- Foundation surprises in pre-1940 garages. Unreinforced masonry and rotting sill plates are the rule, not the exception, in Easton Addition and Lyon-Hoag. Seismic retrofitting adds real money before framing starts, and any contractor who doesn’t flag it early is setting you up for a change order.
- Water table failures from “Burlingame basement” digs. Digging down for ceiling height without proper drainage and waterproofing leads to mold, damp drywall, and failed inspections. We see this on jobs where corners were cut elsewhere.
- Floor-area ratio overruns that stall design review. Burlingame’s strict FAR limits mean a plan that’s 100 square feet too big gets bounced back and redesigned. That costs months, not days. We run FAR calcs before we draw a single wall.
- Fog-driven moisture issues in poorly insulated additions. Burlingame’s marine layer keeps things cool, but it also keeps things damp. Vapor barriers, proper insulation, and exterior drainage matter more here than they do ten miles inland.
Pricing for Home Addition Contractor in Burlingame, CA
Here’s what we tell Burlingame homeowners before any drawings are made. A garage-to-ADU conversion runs $120,000 to $220,000. A bathroom addition runs $55,000 to $110,000. A room addition or bump-out runs $90,000 to $160,000. A second-story addition runs $250,000 to $450,000. Those numbers include permits, materials, labor, and our written price guarantee. What moves the price: seismic retrofitting, excavation depth, plumbing reroutes, and the finish level you choose. What doesn’t move it: our word. The price we put in writing is the price you pay. Call (424) 328-5746 for a free estimate and we’ll give you line items, not a vague ballpark.
We Also Serve Cities Near Burlingame
Our crews serve Burlingame and the surrounding peninsula communities, including El Granada, Half Moon Bay, San Francisco, and Castro Valley. Scheduling and dispatch run from our San Francisco Bay Area office, so you get the same written-price process whether your project is a detached garage in Lyon-Hoag or a sunroom two exits away. The drive time is short and the pricing stays honest.
Serving Burlingame, CA - Our Local Coverage Area
We’re based in the Burlingame 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 Home Addition Contractor in Burlingame
Yes, you need a licensed structural engineer for any Burlingame garage conversion involving foundation work, seismic retrofitting, or excavation. The city requires stamped drawings for those scopes, and honestly, you want an engineer involved. Burlingame’s pre-1940 garages have load-bearing quirks that a drafter won’t catch. We coordinate the engineer and include the cost in our written price. Call (424) 328-5746 to get started.
A “Burlingame basement” is the local practice of digging down beneath a detached garage to gain enough ceiling height for a legal ADU, rather than raising the roof. It affects cost significantly: excavation, waterproofing, and drainage typically add $30,000 to $70,000 depending on depth and soil conditions. Burlingame’s high water table means you cannot skip the moisture management. We budget for it on every single garage conversion.
For a historically sensitive ADU in Burlingame, plan on 3 to 6 months for design review before you get a building permit. The city looks closely at rooflines, materials, and massing in the Easton Addition and Lyon-Hoag historic districts. A well-prepared submittal with a design that matches the existing home will move faster than a modern box that fights the neighborhood character. We prepare those drawings correctly the first time. Call (424) 328-5746 for a free estimate and timeline.
Yes, you can. Burlingame’s climate is mild enough that air conditioning is rarely required by code for ADUs, and most of our garage conversions rely on cross-ventilation, ceiling fans, and good insulation. Proper moisture management is the real priority here, given the fog and high water table. We’ll design for comfort without selling you a system you don’t need.
The single biggest cost driver is the foundation and seismic retrofit required on pre-1940 detached garages. In Easton Addition and Lyon-Hoag, unreinforced masonry foundations routinely need $25,000 to $45,000 in structural upgrades before framing can begin. That is not optional, and it’s the line item most commonly left out of lowball estimates. We put it in writing from day one, and we don’t change it later.
Written by Troy Eastman, Owner at Benson ADU San Francisco, serving Burlingame and the surrounding peninsula.
