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Get your free estimateADU Company in San Marino, CA
Fielding ADU Builders handles accessory dwelling units, garage conversions, and room additions across San Marino, where the homes are large, architecturally distinct, and almost always on lots of half an acre or more. Most of the housing stock dates from the 1920s through the 1950s, and the Spanish Colonial, Mediterranean, and Tudor Revival styles that define those neighborhoods don’t take kindly to generic bolt-on structures. What makes San Marino work different is the same thing that makes it worth doing right: the city reviews accessory structures closely, the houses have real architectural character, and the finished project needs to look like it belongs. Call (626) 657-5541 to talk through your project and get a written price before any work starts.
Why San Marino Homes Are Different
San Marino is not a typical suburban grid. The lots in the estate districts west of San Marino Avenue routinely exceed half an acre, and the primary residences often top 4,000 square feet. Many were custom-built in the Period Revival styles between the 1920s and 1950s, which means an ADU or addition here gets measured against detailing that predates modern construction methods: clay tile roofing, hand-troweled stucco, wood windows with true divided lites, and mature oak and camphor trees that the city takes seriously.
That context changes the work in three ways. First, San Marino’s design review process requires accessory structures to be clearly subordinate to the main house, and the city’s guidelines push many homeowners toward attached ADUs, basement conversions, or garage conversions rather than a detached unit that reads as a second house on the lot. Second, the setback rules on older estate lots are rarely forgiving; a setback variance (the city’s written permission to build closer to the property line than the standard rule allows) becomes part of the conversation more often here than in neighboring cities. Third, the climate shapes the build itself. Mild, wet winters and hot, dry summers mean the envelope has to handle both, with insulation and ventilation specified properly so the new space doesn’t cook in August or stay damp in February. Drought-tolerant landscaping around the new footprint is standard practice, not an afterthought.
None of this is a reason to avoid building in San Marino. It’s a reason to price the job honestly up front, pull the permits, and design to the street rather than to the catalog. That’s how we work.
Our Main San Marino Services
San Marino homeowners most often call us about three things: adding square footage to the main house, converting an existing garage into living space, and building a new ADU in the rear yard or over a detached garage. Each job pulls different permits and faces different design review hurdles here, and each has its own page with local pricing detail.
Room Addition Contractor in San Marino
A room addition on a 1920s Mediterranean in San Marino is a different job than a room addition on a 1990s tract house. The roofline has to tie in convincingly, the stucco texture and color have to be matched to the existing walls, and the foundation work often means digging next to mature tree roots the city may protect. We build additions that pass design review because they’re drawn to match the primary residence, not fight it. Written price first, permit pulled, one-year written guarantee on the work. Room Addition Contractor in San Marino
Garage Conversion Contractor in San Marino
Garage conversions are the most common ADU path in San Marino because they work with the city’s “clearly subordinate” requirement by definition: the structure already exists, already sits behind or beside the main house, and already reads as accessory. The work is in the conversion itself – raising the floor to living-space standards, insulating the walls and slab, replacing the garage door with a wall that matches the house, and running new electrical, plumbing, and HVAC. On Tudor and Spanish Colonial homes, the replacement wall and any new windows have to match period detailing, which is where a lot of generic bids go wrong. Garage Conversion Contractor in San Marino
ADU Builders in San Marino
Detached ADUs in San Marino require the most design sensitivity of any project we take on. Setbacks on older estate lots, mature landscaping, and the city’s requirement that new accessory structures stay visually subordinate to the main house mean the ADU has to be designed for the specific lot, not picked from a standard plan set and dropped in the rear yard. We work with prefab platforms like Abodu, Cover, and Dvele, and we also build conventional stick-frame ADUs with James Hardie siding when the design calls for a more traditional match to the primary residence. ADU Builders in San Marino
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 build with the platforms San Marino homeowners are already researching: Abodu, Cover, and Dvele for prefab and modular ADUs, and James Hardie siding on conventional builds where the finish needs to match an existing Period Revival exterior. Our brands page covers the full list and what each platform does well.
Pricing for ADU Company in San Marino, CA
| Service | Typical range in San Marino |
|---|---|
| Garage conversion to studio ADU | $95,000 – $145,000 before permit fees |
| Garage conversion to one-bedroom ADU | $120,000 – $185,000 before permit fees |
| Garage conversion to two-bedroom ADU | $165,000 – $240,000 before permit fees |
| Prefab/modular studio ADU | $140,000 – $210,000 before permit fees and site work |
| Prefab/modular one-bedroom ADU | $170,000 – $260,000 before permit fees and site work |
| Prefab/modular two-bedroom ADU | $210,000 – $320,000 before permit fees and site work |
| Conventional (stick-built) studio ADU | $180,000 – $260,000 before permit fees |
| Conventional one-bedroom ADU | $210,000 – $310,000 before permit fees |
| Conventional two-bedroom ADU | $250,000 – $375,000 before permit fees |
| Room addition (300-500 sq ft) | $110,000 – $190,000 before permit fees |
| Primary suite addition | $130,000 – $220,000 before permit fees |
| Second-story addition | $180,000 – $300,000 before permit fees |
San Marino pricing runs toward the upper end of these ranges when the lot requires a setback variance, the design review process triggers discretionary review, or the primary residence demands high-end material matching on the new structure. Whatever the project, the price goes in writing before any work starts, and the number you approve is the number on the final invoice.
Neighborhoods We Serve in San Marino
We work across all of San Marino, from the estate districts west of San Marino Avenue to the more modest (by San Marino standards) homes near the eastern edge of the city. Crews are dispatched from our Los Angeles office and serve San Marino locally, so scheduling follows the same pattern as the rest of the San Gabriel Valley.
- West of San Marino Avenue (estate district)
- Huntington Drive corridor
- Lacy Park area
- Valentine School district
- South San Marino / Oak Grove area
Service Area – Cities Near San Marino
San Marino sits in the western San Gabriel Valley, surrounded by cities with their own housing stock and permit quirks. We also serve Pasadena, CA, Temple City, CA, Arcadia, CA, and South El Monte, CA, each with a dedicated page covering local pricing and conditions. If you’re on the border between San Marino and one of these cities, call and we’ll confirm which municipality governs your address and which permits apply.
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
Most San Marino ADU and addition projects spend four to eight weeks in city review, and estate district projects that trigger discretionary review can run longer. The single biggest schedule variable is whether your plans read as subordinate to the main house on the first submittal. We draw them that way up front. Call (626) 657-5541 to talk through your specific lot and timeline.
Many detached ADUs on older estate lots do require a setback variance, which the city grants in writing when the project meets its design standards. Attached ADUs and garage conversions often avoid the variance entirely, which is one reason they’re the more common path in San Marino. We’ll tell you which applies to your lot before you commit to a design.
Yes. Every San Marino project is permitted through the city, and we handle the plans, submittals, corrections, and inspections from start to finish. No work starts without the permit in hand. Call (626) 657-5541 for a free estimate and a written price before any work begins.
For a written price on an ADU, garage conversion, or room addition in San Marino, call Fielding ADU Builders at (626) 657-5541. Someone answers the phone 24/7, and the estimate is free.
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
"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."Garage conversion with a new bath and kitchenette. Permit was handled by them. Inspection passed first time."
- Sheila B."Insulation, drywall, and finishes were all well done. Feels like part of the house."
- Pete O.
