A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in San Marino, CA
Fielding ADU Builders handles ADU construction, garage conversions, and room additions in San Marino, CA. Most San Marino properties sit on larger lots than you’ll find in Pasadena or Alhambra, which changes setback math, drainage planning, and where a detached unit can realistically go. Homes here skew older, many built between the 1920s and 1950s, and that means foundation conditions, existing electrical service, and original framing all factor into the written price before work starts. If you’re planning an ADU, a garage conversion, or a room addition in San Marino, call (361) 315-4177 for a free estimate and a line-item price you can hold us to.
Why San Marino Homes Are Different
San Marino, CA is a city of established neighborhoods with mature trees, deep setbacks, and a housing stock that was largely built before modern building codes existed. That changes how we approach an ADU or addition from the first site visit. Older homes often have 100-amp electrical panels that need upgrading before a new unit can be tied in. Foundations from the 1920s and 1930s may have settled, which affects how a room addition ties into the existing structure. Large oak and sycamore trees common in San Marino trigger root-protection requirements during excavation, and the city reviews plans with an eye toward preserving the character of streets like Lorain Road, Winston Avenue, and Sierra Madre Boulevard.
Climate matters too. San Marino gets hot, dry summers and occasional heavy rain in winter, so we plan roof tie-ins, flashing details, and drainage for both extremes. The city’s permit process is rigorous and methodical. San Marino reviews ADU and addition plans against its own zoning rules, including setback requirements and lot-coverage limits. That is exactly why our pricing goes in writing before work starts. We account for the permit path, the site conditions, and the build method up front, so the number you approve on day one is the number on the final invoice.
Our Main San Marino Services
San Marino homeowners most often call us about adding square footage to an existing home and converting underused garage space into living quarters. Each service below has its own detailed San Marino page with pricing, timelines, and local permit notes.
Room Addition Contractor in San Marino
Room additions in San Marino typically mean extending a ranch-style home or adding a second-story suite to a traditional two-story. We work with the existing roofline, foundation, and stucco profiles so the addition looks like it was always there. San Marino’s older homes often need structural reinforcement at the tie-in point, and we price that work upfront rather than discovering it mid-project. Permits go through the city’s building department, and we pull them, schedule inspections, and close the permit when the job passes. Learn more on the Room Addition Contractor in San Marino page.
Garage Conversion Contractor in San Marino
Many San Marino homes have detached garages set back from the house, which makes them natural candidates for conversion into a studio, guest suite, or home office. We handle the structural conversion, insulation, drywall, electrical, plumbing, and finish work, plus the permit package the city requires. Older detached garages in San Marino sometimes sit on undersized slabs or have outdated electrical feeds, so we inspect those conditions before writing the price. See specifics on the Garage Conversion Contractor in San Marino page.
ADU Builders in San Marino
Backyard ADUs in San Marino work well on the city’s larger lots, whether you want a detached unit, a garage conversion with living space above, or an attached junior unit. We build conventional ADUs with James Hardie siding and also have fluency with prefab platforms like Abodu, Cover, and Dvele, which can shorten on-site construction time on a San Marino lot where access is tight. Every ADU we build gets the same written price before work starts and the same 365-day written guarantee. Details are on the ADU Builders in San Marino 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 Marino
We install and tie in work from the brands San Marino homeowners already research, and we keep local parts access for faster turnarounds. Abodu, Cover, and Dvele prefab units, James Hardie siding and trim, and conventional stick-built framing all fall under the same written-price and written-guarantee terms. See our brands for the full list of platforms we work with.
Pricing for ADU Company in San Marino, CA
These ranges reflect what we typically see on San Marino jobs before permit fees. Your written quote will be specific to your lot, your existing structure, and your build method.
| Service | Typical range in San Marino |
|---|---|
| Detached backyard ADU (prefab, standard finish) | $180,000 – $280,000 |
| Detached backyard ADU (conventional build) | $250,000 – $400,000 |
| Garage conversion to ADU | $120,000 – $190,000 |
| Garage conversion to living space (no kitchen) | $70,000 – $120,000 |
| Room addition (single story, simple tie-in) | $90,000 – $160,000 |
| Room addition (primary suite with bath) | $140,000 – $220,000 |
| Second-story addition | $200,000 – $350,000 |
| Electrical panel upgrade (100A to 200A) | $3,500 – $6,000 |
San Marino pricing pushes higher when a job requires foundation repair, extensive root protection, or a full re-roof at the tie-in point. Whatever the final scope, the price goes in writing before any work starts and does not move unless you approve a change order in writing.
Neighborhoods We Serve in San Marino
We work throughout San Marino, CA, from the streets around Huntington Drive up to the hillside lots near Lacy Park and the neighborhoods west of San Gabriel Boulevard. Response times for estimates in San Marino run one to three business days depending on our crew schedule, and we coordinate from our Los Angeles office with local crews serving the city directly.
- Lacy Park area
- Huntington Drive corridor
- San Gabriel Boulevard west side
- Winston Avenue and Lorain Road area
- Sierra Madre Boulevard corridor
Service Area – Cities Near San Marino
Beyond San Marino, we serve homeowners in San Gabriel, CA, Alhambra, CA, Pasadena, CA, and South Pasadena, CA. If you’re in a neighboring city and planning an ADU, garage conversion, or room addition, the same written-price policy and one-year guarantee apply. Call (361) 315-4177 and we’ll schedule a free estimate at your property.
Serving San Marino, CA - Our Local Coverage Area
We’re based in the San Marino 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 Marino
We typically schedule free estimates in San Marino within one to three business days. A live person answers every call, day or night, so you can call (361) 315-4177 any time and get a confirmed appointment window without leaving a voicemail.
We handle city permits directly: plan submittal, plan-check corrections, inspections, and permit closeout. If your property falls under an HOA with architectural review, we prepare the drawings and documentation they request. The permit path is factored into your written price before work begins. Call (361) 315-4177 with your address and we’ll tell you exactly what San Marino requires.
No. The price you approve in writing before work starts is the price on the final invoice, unless you request a change or the city mandates one during plan check. Every San Marino job is backed by the 365-Day Done Right Promise: if something fails within one year, we return and correct it at no charge. Call (361) 315-4177 for a free estimate.
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 Marino Customers Say
"Insulation, drywall, and finishes were all well done. Feels like part of the house."
- Pete O."Built a detached ADU behind our house. The builder is a veteran and runs the site like a platoon: schedule posted, crew on time, everything labeled. Finished within a few days of the date."
- Ken W."Room addition over the back patio. Framing is square, windows are tight, and the roofline matches."
- Danny L.
