The right ADU builder in Mountain View, CA is a licensed general contractor who handles feasibility, design, permitting, and construction under one contract — not a broker who subs out the work. Construction Remodeling in Bay Area (CRBA) is a CSLB-licensed ADU contractor Mountain View CA homeowners have called since 2015, building detached, attached, and garage-conversion accessory dwelling unit Mountain View projects with an in-house crew and a fixed-price contract.
By Ray Evgeny Khaikin, Owner & General Contractor · Last updated August 2026
A full-service ADU builder Mountain View CA homeowners can rely on handles six things under one roof: lot feasibility, architectural plans, structural engineering, city plan check, utility connections, and the final inspection that makes the unit a legal, rentable dwelling. Split those steps across an architect, a separate permit expediter, and a general contractor, and you inherit the finger-pointing when something doesn’t line up at inspection.
CRBA runs feasibility, design, permitting, and construction as one contract with one crew. That matters more in Mountain View than in most Bay Area cities, because Santa Clara County lots tend to be smaller and older Eichler and ranch-style homes often carry non-standard setbacks — the kind of detail that stalls a project when the plan-check reviewer and the framing crew have never talked to each other.
Mountain View lots generally support a detached backyard ADU up to roughly 1,200 square feet for a two-bedroom unit, an attached addition, a junior ADU (JADU) built inside the existing footprint, or a garage conversion. We’ve written a deeper cost breakdown specifically on garage conversion in Mountain View if that’s the path you’re weighing — this page covers the full range of ADU types.
A detached ADU in Mountain View typically runs $300,000–$500,000 for a full custom build, largely because Silicon Valley labor rates and utility-trenching costs run higher than the wider Bay Area average. A garage conversion is the least expensive path since the foundation, walls, and roof already exist; an attached addition or JADU lands in between.
Roughly six factors move that number: ADU type, finished square footage, how far utilities have to run to reach the structure, site conditions (slope, soil, tree protection), finish tier, and city plan-check fees. CRBA gives a phone-range estimate first, then a free on-site feasibility visit and a written, itemized quote before anything is signed — no allowance buried in a lump sum.
California law requires cities to approve compliant ADU applications ministerially — meaning no public hearing and no discretionary design review — under the state’s Accessory Dwelling Unit statutes, consolidated under Government Code sections 66310–66342. Local ordinances can’t be more restrictive than the state standard, and recent legislation has permanently removed owner-occupancy requirements for most ADUs. Understanding these rules early can also help answer how long it takes to build an ADU, since a compliant application can move through the approval process without discretionary review.
Mountain View applies these rules through its own ADU permitting program, which does not require a separate planning permit for a compliant project — only a standard building permit. If a previous owner built a garage conversion without permits, the city also runs a legalization program that lets a current owner correct the work without facing fines.
Homeowners searching for the best ADU builder near me Mountain View CA usually land on one of two options: a design-only firm that hands construction to a sub, or an in-house contractor who owns the whole build. CRBA is the second kind — one license, one crew, one accountable name (Ray’s) on every permit. One Bay Area client who compared five contractors before hiring CRBA said the estimate was straightforward and the crew, including framers Nino and Alex, stayed easy to work with through the entire project.
We build ADUs across Old Mountain View, Cuesta Park, Monta Loma, Rex Manor, and Waverly Park — the last two known for larger, ranch-style 1960s–80s lots that tend to have the backyard depth a detached ADU needs — plus nearby Palo Alto, Sunnyvale, Los Altos, Cupertino, and Santa Clara. Anyone searching for an accessory dwelling unit contractor Mountain View California can call and get a coverage answer in under a minute; if you’re searching for an ADU builder near me Mountain View, that’s this crew.
Every job carries a 10-year workmanship warranty — ten times the industry standard.
How much does an ADU cost in Mountain View, CA? A detached custom ADU typically costs $300,000–$500,000; garage conversions run lower since the structure already exists. Site conditions, utility distance, and finish tier are the biggest swing factors — CRBA confirms your real number at a free feasibility visit.
What are California’s ADU laws in 2026? State law requires ministerial approval (no hearings, no discretionary review) for compliant ADUs, bans owner-occupancy requirements on most units, and prevents cities from imposing standards stricter than the state baseline under Government Code §§66310–66342.
Do I need a permit for an ADU in Mountain View? Yes. Every ADU needs a building permit; compliant projects don’t require a separate planning permit. CRBA handles plan submittal, Title 24 calculations, and every required inspection.
How long does it take to build an ADU? Roughly 8–14 months total for a detached unit, including 1–2 months of feasibility and plans and 4–6 months of city permitting. Garage conversions and JADUs typically finish in 5–8 months.
Does an ADU add rental income and home value? Yes. A permitted ADU adds appraisable square footage and a steady rental income stream, and it can make a property more attractive to future buyers — though it also triggers a property tax reassessment limited to the new construction’s value.
CRBA handles feasibility, plans, permits, and construction under one fixed-price contract — no subs, no finger-pointing, and a 10-year warranty on the finished work. Contact us at (510) 990-9243, visit our ADU construction service page for the full range of ADU types, or browse the project portfolio to see real Bay Area builds.