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
Sutton ADU Builders is the ADU company San Marino homeowners call when they want a written price before any work begins and proof of who’s coming to the property before the door opens. San Marino jobs run on older lots with mature tree canopies, strict design-review standards, and homes where a detached ADU or addition has to look like it belonged there from the start. That’s the work we do best. Call (472) 248-8213 and we’ll walk you through what’s possible on your lot.
Why San Marino Homes Are Different
San Marino is not a tear-down town. The housing stock skews older – a meaningful share of the homes were built between the 1920s and 1950s – and the city’s design review process treats architectural character as something to protect, not negotiate around. That changes how an ADU or addition gets designed and permitted here. A detached ADU in San Marino often needs to respect existing rooflines, setback requirements (the required gap between your new structure and the property line), and the sightlines your neighbors have lived with for decades.
Lot sizes help. San Marino parcels are generally larger than what you’d find in Pasadena or Alhambra, which means a detached ADU is a realistic option for many homeowners rather than a squeeze. But mature landscaping complicates things: protected oak trees, deep root systems, and established hedgerows can shift where a foundation can go. We work through those constraints at the estimate stage so the written price you approve reflects the actual site, not a best-case drawing.
Our Main San Marino Services
Most San Marino homeowners call us for one of three things: a detached ADU, a room addition, or a larger home addition that expands the main house. Each has its own San Marino page with pricing and local details.
Home Addition Contractor in San Marino
A home addition in San Marino usually means adding square footage to an older home while keeping the original footprint’s character intact. That matters here because the city reviews additions for how they relate to the existing structure – a jarring, modern box bolted onto a 1930s Spanish Revival is a fast way to get a design-review rejection. We plan additions around matching rooflines, window proportions, and exterior materials so the new work reads as part of the original house. See pricing and process details on our Home Addition Contractor in San Marino page.
ADU Builders in San Marino
San Marino’s larger lots make detached ADUs a strong option, and California’s statewide ADU rules mean a single ADU up to 800 square feet is generally allowed regardless of local zoning mood. The real constraint here is design review and site fit – trees, setbacks, utility routing. We build both site-built ADUs and prefab/modular units from brands like Abodu and Dvele, which can shorten on-site construction time significantly. Full pricing ranges and specific San Marino considerations are on our ADU Builders in San Marino page.
Room Addition Contractor in San Marino
A room addition is the smallest scale of work we do in San Marino – a single bedroom, a home office, an expanded kitchen – but it still goes through the same design-review and permitting process as a larger project. That’s why we price room additions with the same written, line-item detail as a full ADU. You’ll know what the permit drawings cost, what the foundation work costs, and what the finish work costs before any commitment. The Room Addition Contractor in San Marino page breaks down typical ranges for this scale of work.
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 work with prefab and modular ADU product lines including Abodu, Cover, and Dvele, and we install James Hardie exterior systems on both new and addition work. Parts for these systems are routed through our regional suppliers, which keeps lead times short for San Marino builds. See our brands for the full list of product lines we service.
Pricing for ADU Company in San Marino, CA
| Service | Typical range in San Marino |
|---|---|
| Detached ADU (600 – 800 sq ft, site-built) | $180,000 – $320,000 |
| Detached ADU (prefab/modular, e.g., Abodu or Dvele) | $150,000 – $280,000 |
| Garage conversion to ADU | $90,000 – $160,000 |
| Home addition (400 – 600 sq ft) | $120,000 – $220,000 |
| Home addition (600 – 1,000 sq ft) | $180,000 – $320,000 |
| Room addition (single room, 150 – 300 sq ft) | $60,000 – $130,000 |
| Kitchen addition | $90,000 – $180,000 |
| Primary suite addition | $110,000 – $230,000 |
| Tuff Shed conversion to livable space | $35,000 – $70,000 |
| Foundation-only work (new ADU slab or raised) | $18,000 – $42,000 |
What pushes pricing up in San Marino specifically is site prep – tree root mitigation, slope correction, and the extra design-review documentation the city asks for. Every project gets a written price before any work starts, and that price holds unless the scope of work changes in writing.
Neighborhoods We Serve in San Marino
We work across the full city of San Marino, from the streets north of Huntington Drive down through the neighborhoods around Lacy Park. If you’re inside the San Marino city limits, you’re in our service area.
- Lacy Park area
- North San Marino (north of Huntington Drive)
- South San Marino (near the San Marino/San Gabriel boundary)
- Huntington Drive corridor
- Valentine School district area
For estimate appointments in San Marino we typically schedule within one to two weeks, depending on how full the project calendar is at the time you call.
Service Area – Cities Near San Marino
While this page covers San Marino specifically, we also work in the neighboring communities of San Gabriel, CA, Alhambra, CA, Pasadena, CA, and South Pasadena, CA. Each city has its own page with local pricing and permit details.
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
Yes. San Marino requires design review for most ADU and addition work, and we prepare the drawings and documentation the city asks for before submitting anything. You don’t need to know the permitting process – that’s our job. Call (472) 248-8213 and we’ll tell you what your specific project will need.
Most ADU and addition projects in San Marino run four to nine months from first drawings to final inspection, with design review adding time at the front end. Prefab or modular units can shorten on-site construction to a few weeks once the foundation and utilities are in. We’ll give you a written timeline with your estimate.
Every person who arrives at your San Marino property works under the Threshold Standard: background-checked, identity-verified, uniformed, and photo-badged. We send you their name and photo before the visit so you know exactly who’s at the door. Call (472) 248-8213 for a free estimate and we’ll walk you through the whole process.
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
"Itemized estimate with allowances laid out. Final cost was within a hair of the quote."
- Naomi R."Backyard ADU for my mother. The project manager showed ID and walked me through the permit steps, the foundation plan, and the schedule. Moved her in on time."
- Margaret C."Insulated the walls and ceiling properly. It stays comfortable even in July."
- Tamika W.
