A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in San Carlos, CA
An ADU, or accessory dwelling unit, is a second, smaller home built on the same lot as your main house. In San Carlos, that usually means a detached backyard unit, a garage conversion, or a home addition with its own entrance. This page is the starting point: what makes San Carlos jobs different, what they cost here, and which neighborhoods we serve. Each service has its own detailed San Carlos page linked below. For a free estimate on any ADU, garage conversion, or home addition project in San Carlos, call (707) 760-0502.
Why San Carlos Homes Are Different
San Carlos has earned its “City of Good Living” reputation through decades of careful, family-first development, and the housing stock reflects that. You’ll find mid-century ranch homes, 1920s through 1950s bungalows, and plenty of newer two-story builds, often on flat, rectangular lots. That lot shape is good news for detached ADUs. A single-story home with a generous backyard leaves room to build without crowding the main house. What slows things down is what’s underneath. Many original 1940s cottages in White Oaks sit on unreinforced brick foundations. Before any ADU construction can start on those properties, the foundation needs seismic retrofitting. We see this regularly and build it into the written estimate from day one rather than surprising you mid-project.
Climate matters too. San Carlos has warm, dry summers and cool, wet winters. A properly built San Carlos ADU needs real insulation for August heat and thoughtful moisture management for the rainy season. Indoor-outdoor living is part of how people live here, so door placement, window orientation, and covered patios become design decisions, not afterthoughts. Where a garage conversion might be simpler in other cities, in San Carlos the goal is usually to make the new space feel like it was always part of the property.
Our Main San Carlos Services
Most San Carlos homeowners we talk to are deciding between three paths: adding square footage to the main house, converting an existing garage, or building a detached ADU in the backyard. Each has its own page with full pricing and San Carlos specifics.
Home Addition Contractor in San Carlos
A home addition in San Carlos means extending the footprint of your existing house, often to add a bedroom, family room, or in-law suite. On the flat lots common here, ground-floor additions make more sense than second-story work in many cases, though both are possible. Older San Carlos homes often need electrical panel upgrades when adding heated square footage, and we include that in the written price before work begins. If you’re weighing an addition against a separate ADU, the right answer depends on your lot, your budget, and how you want to use the space. Learn more on our Home Addition Contractor in San Carlos page.
Garage Conversion Contractor in San Carlos
Converting a garage into living space is often the fastest, most cost-effective way to add a rental unit or guest suite in San Carlos. The garage is already there, already permitted as a structure, and usually already has a roof and foundation. What many San Carlos garages don’t have is insulation, proper drainage, or an electrical service rated for a dwelling. Older single-car garages from the 1940s and 1950s often need foundation work before the conversion can pass inspection. Our crew handles the full scope, from seismic and foundation corrections to finished interiors. See Garage Conversion Contractor in San Carlos for detailed pricing.
ADU Builders in San Carlos
A detached ADU is a standalone small house, and San Carlos is one of the few mid-Peninsula cities where many lots genuinely have room for one. That’s why so many homeowners here choose this route: a lodge, small and self-contained, on the same property as the main home. Prefab ADUs from manufacturers like Abodu and Plant Prefab can shorten the timeline considerably, and we match the right system to your lot, budget, and style. San Carlos planning rules, lot coverage limits, and setback requirements all shape what’s possible, and we walk every project through from first sketch to final inspection. Details are on our ADU Builders in San Carlos page.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Brands We Service in San Carlos
We work hands-on with leading ADU and materials brands, including Plant Prefab, Abodu, Tuff Shed, and James Hardie. Parts and panels are ordered to the job site, and we coordinate delivery windows so your San Carlos project doesn’t stall waiting on materials. See our brands for the full list and what each one does best.
Pricing for ADU Company in San Carlos, CA
Here are the price ranges we quote most often for San Carlos projects. These are planning numbers, not a substitute for a written estimate on your property, but they’ll give you a real place to start.
| Service | Typical Range in San Carlos |
|---|---|
| Detached ADU (prefab, 400 – 600 sq ft) | $180,000 – $320,000 |
| Detached ADU (site-built, 600 – 800 sq ft) | $250,000 – $420,000 |
| Garage conversion (attached, 400 sq ft) | $120,000 – $210,000 |
| Garage conversion (detached) | $140,000 – $240,000 |
| Home addition (ground-floor, 400 – 600 sq ft) | $180,000 – $360,000 |
| Home addition (second-story, 400 – 600 sq ft) | $260,000 – $460,000 |
| Foundation retrofit (unreinforced brick or masonry) | $15,000 – $45,000 |
| Electrical panel upgrade (100A to 200A) | $3,500 – $7,500 |
What pushes a San Carlos price up is usually the foundation, the electrical service, or site access on a tight lot. A White Oaks cottage on a brick foundation will cost more than a 1990s home on a poured slab before a single wall goes up. Whatever the number is, you get it in writing before work starts. No price changes at the door.
Neighborhoods We Serve in San Carlos
We work across San Carlos, from the hillside streets to the flatlands. Most projects in these neighborhoods fall within the same scheduling window, and we’re typically on-site for the first walkthrough within a week of your call.
- White Oaks
- Howard Park
- Beverly Terrace
- Clearfield Park
- Alder Manor
Service Area – Cities Near San Carlos
Our San Carlos crews also cover nearby Peninsula cities when schedules allow. If you live just north of San Carlos, we serve Millbrae, CA, San Bruno, CA, San Lorenzo, CA, and Daly City, CA. Scheduling and dispatch are coordinated from our San Francisco Bay Area office, and every project carries the same written guarantee.
Serving San Carlos, CA - Our Local Coverage Area
We’re based in the San Carlos 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 Company in San Carlos
Most San Carlos ADUs finish in five to nine months from first walkthrough to final inspection. Prefab builds from manufacturers like Abodu and Plant Prefab are faster, usually on the five-to-seven-month end, while site-built units take longer. Permitting, foundation work, and weather can shift the timeline, and your written estimate includes a schedule before work begins. Call us for a free estimate and a real timeline for your lot.
Yes. Every ADU, garage conversion, and home addition in San Carlos requires city permits, and many projects also trigger foundation or electrical reviews. We pull all permits, manage inspections, and stay current with San Carlos building and zoning requirements. You won’t chase paperwork. Call (707) 760-0502 to get started.
No. The written price you receive before work begins is the price. If we find something unexpected, like the unreinforced brick foundations we often see in White Oaks, we stop and bring you a written change order before proceeding. Nothing is added at the door, and nothing is billed without your signed approval.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What San Carlos Customers Say
"The ADU came out beautiful and the permitting, which terrified me, was handled start to finish. They kept me updated every week so I was never wondering what was happening."
- Shauna Mills"Turned our detached garage into a little guest house. Clean crew, respectful of the neighbors, and no mystery charges at the end. Love how it turned out."
- Carmela Fontes"I was nervous about adding on but they walked me through every step and every cost before we started. No surprise change orders halfway through like I'd heard horror stories about."
- Eleanor Pratt
