Your ADU, Designed and Priced Before We Build
Add value and living space to your property, designed in 3D before we break ground.
From detached studios to full guest houses, Custom Home designs and builds ADUs that maximize your property's potential. Our design phase means you see every detail before construction begins.
Years in the Bay Area
Licensed since 2005. Hundreds of projects completed across the South Bay, Peninsula, and beyond.
BuildZoom Rated
Ranked in the top 1% of Bay Area contractors based on qualifications, performance, and reliability.
Design-First Process
See every detail in 3D before construction. Our two-phase approach separates design from build so you never commit blind.
Change Orders
When you follow our full two-phase process from A to Z, every decision is locked in during design. No mid-project surprises.
Itemized Pricing
Every material, every line item, visible before you sign. No allowances, no hidden fees.
Why Choose Custom Home for ADUs
Detached ADUs
Standalone units up to 1,200 sqft with full kitchens, bathrooms, and independent entrances.
Attached ADUs
Connected additions that share a wall with your main home. Efficient use of existing infrastructure.
Garage Conversions
Transform your existing garage into a functional living space. The most cost-effective ADU option.
Full Permit Management
We handle the complete ADU permitting process with your local jurisdiction, from initial plans through final inspection.
What to Expect
Every project is unique. Varies significantly by ADU type: garage conversions from $120K, detached units up to $500K+.
Key Cost Factors
- ADU type (detached, attached, conversion)
- Square footage
- Kitchen and bathroom fixtures
- Utility connections
- City permit requirements
All pricing is approximate and subject to change. Every project is unique, and final costs are determined on a project-by-project basis during our design phase.
Ready to discuss your adus project? Call (888) 306-1688 or schedule a consultation.
Frequently Asked Questions
How much does an ADU cost in the Bay Area?
ADU costs in the Bay Area range from $120,000 for a garage conversion to $500,000+ for a large detached unit. The biggest factors are size, type, and finishes. Our design phase gives you exact costs before you commit.
Do I need a permit for an ADU?
Yes. All ADUs require building permits. California state law (AB 68, SB 13) has streamlined the process, and many cities like San Jose offer pre-approved ADU plans. We handle the complete permitting process.
Can I rent out my ADU?
Yes. California law allows homeowners to rent ADUs. Many Bay Area homeowners use ADUs for rental income, helping offset mortgage costs. Check your local zoning for any restrictions.
How long does it take to build an ADU?
Typical ADU projects take 6-12 months from design to move-in. Garage conversions are fastest (4-6 months), while detached units take 8-12 months including permits.