Acton ADU
ADU specialist with Build Ready and Custom site-built paths
Model ADU Builders / ADU Companies +3
Cities Campbell, Cupertino, Los Altos, Los Gatos, Mountain View, Palo Alto, San Jose, Santa Clara, Saratoga, Sunnyvale
ADU builders directory
Bay Area ADU Builders Directory
Filter ADU specialists, prefab companies, design-build teams, garage conversion providers, and planning-first options by city, scope, permit support, and project fit.
Need a shortlist?
Send the city, ADU type, and stage. The useful answer is whether you need feasibility, drawings, permit help, builder fit, or a clear reason to pause.
No matching providers yet. That is a data problem, not a UI problem.
Adapt Dwellings
Feasibility-first ADU planning, legalization, and multifamily conversion analysis
Model ADU Builders / ADU Companies +3
Cities Burlingame, Fremont, Redwood City, San Jose, San Mateo
FabuHome
Budget-first ADU planning and design-build path
Model ADU Builders / ADU Companies +3
Cities Burlingame, Cupertino, Los Gatos, Mountain View, Palo Alto, Redwood City, San Jose, San Mateo, Santa Clara, Saratoga, Sunnyvale
H2 Prefab
Modern detached prefab ADU for difficult-access Bay Area sites
Model ADU Builders / ADU Companies +1
Cities Burlingame, Fremont, Mountain View, Palo Alto, Redwood City, San Jose, San Mateo, Santa Clara
HAUS+
Full-service hybrid prefab ADU for design-forward Bay Area yards
Model ADU Builders / ADU Companies +2
Cities Burlingame, Fremont, Mountain View, Palo Alto, Redwood City, San Jose, San Mateo, Santa Clara, Sunnyvale
Inspired ADUs
Architect-led ADU design, permitting, plan catalog, and builder-selection support
Model ADU Builders / ADU Companies +3
Cities Los Gatos, Palo Alto, Redwood City, San Jose, San Mateo
Red Shed Studio
Custom ADU design-build and garage conversion for San Jose/South Bay lots
Model ADU Builders / ADU Companies +3
Cities Los Gatos, Mountain View, Palo Alto, San Jose, Santa Clara, Saratoga, Sunnyvale
The ADU Dudes
ADU coordination with Signature plans and licensed-contractor construction path
Model ADU Builders / ADU Companies +2
Cities Burlingame, Fremont, Milpitas, Mountain View, Palo Alto, Redwood City, San Jose, San Mateo, Santa Clara, Sunnyvale
Villa
Prefab detached ADU with turnkey delivery and permit support
Model ADU Builders / ADU Companies +1
Cities Cupertino, Fremont, Mountain View, Palo Alto, Redwood City, San Jose, San Mateo, Santa Clara, Sunnyvale
VitalizeBuild Construction
Custom and predesigned ADU design-build for complex Bay Area lots
Model ADU Builders / ADU Companies +3
Cities Campbell, Cupertino, Fremont, Los Altos, Milpitas, Mountain View, Palo Alto, Redwood City, San Jose, San Mateo, Santa Clara, Saratoga, Sunnyvale
Narrow the list
Match the builder to the project before requesting bids.
A homeowner with no drawings should not compare the same companies as a homeowner with permit-ready plans. Use city, ADU type, stage, and scope ownership first; then compare names.
Where City first San Jose, Santa Clara, Sunnyvale, Palo Alto, Peninsula
Project ADU type Detached, prefab, garage conversion, JADU, attached ADU
Stage Readiness Researching, needs plans, has drawings, ready for bids
Scope Who owns what Feasibility, drawings, permits, site work, construction
Best fit shortlists
Pick the ADU path before picking a company.
These are not fake rankings. They are project-fit starting points based on source-backed provider positioning, city coverage, service model, and unresolved verification notes.
Planning-first
You need cost and feasibility before drawings
Best when budget, zoning, utility path, or permit-plan risk is still unclear.
Ask before hiring
What will I know before paying for full drawings?
Prefab detached
You want a detached prefab ADU
Compare the installed project scope, not just the unit price.
Ask before hiring
Are foundation, utilities, delivery access, plans, and permit corrections included?
Garage conversion feasibility
You are converting a garage
Start with existing-structure risk before pricing finishes.
Ask before hiring
Who checks fire separation, slab, ceiling height, moisture, windows, and utility upgrades?
Construction-ready bid review
You already have plans
Now the key is bid comparability: exclusions, allowances, schedule, and inspection ownership.
Ask before hiring
What is excluded, and who pays if the city asks for corrections?
Design and permit support
You want design help without committing to one builder
Useful when you need plans, code checks, or builder selection help before construction.
Ask before hiring
Does this team build, design only, or coordinate a separate contractor?
Comparison table
Make providers comparable before comparing bids.
Use this as the shortlist layer. Then open profiles for source notes, fit questions, city coverage, and verification limits.
| Provider | Best fit | Services | Priority cities | Verification |
|---|---|---|---|---|
| Acton ADU | ADU specialist with Build Ready and Custom site-built paths | ADU Builders, ADU Companies, ADU Contractors, Design-Build | Campbell, Cupertino, Los Altos, Los Gatos, Mountain View | Official service pages reviewed; license #638333 published; current license status, scope, and city fit still need verification |
| FabuHome | Budget-first ADU planning and design-build path | ADU Builders, ADU Companies, ADU Contractors, Design-Build | Burlingame, Cupertino, Los Gatos, Mountain View, Palo Alto | Official ADU page reviewed; license and role still need confirmation |
| Villa | Prefab detached ADU with turnkey delivery and permit support | ADU Builders, ADU Companies, Prefab ADUs | Cupertino, Fremont, Mountain View, Palo Alto, Redwood City | Official Bay Area and product pages reviewed; license and registration numbers noted; project-specific pricing and city fit still need verification |
| Red Shed Studio | Custom ADU design-build and garage conversion for San Jose/South Bay lots | ADU Builders, ADU Companies, ADU Contractors, Design-Build | Los Gatos, Mountain View, Palo Alto, San Jose, Santa Clara | Official ADU, San Jose, how-it-works, and guide pages reviewed; CA license #1137392 published; current license status, insurance, and project-specific scope still need verification |
| VitalizeBuild Construction | Custom and predesigned ADU design-build for complex Bay Area lots | ADU Builders, ADU Companies, ADU Contractors, Design-Build | Campbell, Cupertino, Fremont, Los Altos, Milpitas | Official ADU pages reviewed; CA license #1104475 published; current license status, insurance, and project-specific scope still need verification |
| HAUS+ | Full-service hybrid prefab ADU for design-forward Bay Area yards | ADU Builders, ADU Companies, Design-Build, Prefab ADUs | Burlingame, Fremont, Mountain View, Palo Alto, Redwood City | Official homepage, FAQ, about page, and Model 350/500/650/1200 pages reviewed; contractor/license structure, final installed price, city-specific permit path, and site condition assumptions still need verification |
| H2 Prefab | Modern detached prefab ADU for difficult-access Bay Area sites | ADU Builders, ADU Companies, Prefab ADUs | Burlingame, Fremont, Mountain View, Palo Alto, Redwood City | Official H2 homepage, pricing, model, ADU info, and MESH partner pages reviewed; model availability, HCD/local permit path, license/installer responsibility, and site-specific pricing still need verification |
| The ADU Dudes | ADU coordination with Signature plans and licensed-contractor construction path | ADU Builders, ADU Companies, ADU Contractors, Garage ADUs | Burlingame, Fremont, Milpitas, Mountain View, Palo Alto | Official pages reviewed; San Andres Construction license #1081083 and independent-contractor structure noted; contract, insurance, warranty, and exclusions still need verification |
| Inspired ADUs | Architect-led ADU design, permitting, plan catalog, and builder-selection support | ADU Builders, ADU Companies, Design-Build, Garage ADUs | Los Gatos, Palo Alto, Redwood City, San Jose, San Mateo | Official homepage, process, plans, panelized, prefab, builder-selection, and project pages reviewed; California Architect License No. C-29312 published; construction responsibility, engineering/survey/Title 24 scope, builder network, and project-specific pricing still need verification |
| Adapt Dwellings | Feasibility-first ADU planning, legalization, and multifamily conversion analysis | ADU Builders, ADU Companies, ADU Contractors, Design-Build | Burlingame, Fremont, Redwood City, San Jose, San Mateo | Official Edrington/Adapt ADU consulting page, Adapt case study, Oakland ADU article, and feasibility-study article reviewed; DRE #01129470 and CSLB #1098831 referenced publicly; current license status, contract party, construction scope, and city-specific responsibilities still need verification |
Bid checklist
The questions that prevent bad comparisons.
If two builders are pricing different scopes, the cheaper bid is not cheaper; it is just missing work.
Which city submittal, plan check, and correction work is included?
Are survey, engineering, Title 24, utility trenching, panel upgrades, and fees included or excluded?
Is the number a planning range, a design contract, or a construction bid?
Who owns permit corrections, inspection coordination, and change orders?
What exact ADU type is this builder strongest at: prefab, custom detached, garage conversion, or design-build?
What proof exists: official pages, license hooks, city examples, portfolio, references, or owner-supplied data?
Project types
Do not compare every ADU company as if they solve the same problem.
Detached custom ADUs, prefab units, garage conversions, JADUs, and design-only plans create different risks. The shortlist should follow the risk.
Planning-first
Best when the homeowner needs feasibility, budget range, zoning review, or drawings before construction bids make sense.
Prefab vs custom
Prefab can reduce design ambiguity, but site work, foundation, access, utilities, local plan changes, and inspections still decide the real number.
Construction-ready
Best when drawings, site assumptions, permit status, and specifications are clear enough for builders to price the same scope.
City fit
Start with the city that will review the permit.
ADU builder fit changes by local review pattern, utility constraints, lot condition, and city process. These city pages are the local depth layer.
Buying notes
How to choose an ADU builder in the Bay Area.
Ask whether the team can price from a real scope, not a napkin sketch and optimism.
Separate drawings, permit support, utility/site work, and construction management in every proposal.
Verify city experience for your property. San Jose, Sunnyvale, Cupertino, Palo Alto, and San Mateo do not behave like one generic Bay Area blob.
For garage conversions, ask about fire separation, ceiling height, slab, drainage, parking, and utility constraints early.
For prefab ADUs, confirm what is included after delivery: foundation, utility trenching, crane access, site-specific plans, and permit coordination.
Methodology
How this directory stays useful.
This page compares project fit, not fake five-star certainty. Profiles separate source-backed signals from unresolved verification so homeowners know what to confirm before hiring.
Source-backed signals
Provider fit is based on public source notes, owner-supplied information, service categories, city coverage, and visible ADU positioning.
Verification is separate
Verification status is not a quality rating. License, insurance, current scope, and permit responsibility should be confirmed before hiring.
No fake ranking glitter
“Best fit” means a practical starting point for a project type. It is not a review score, guarantee, or substitute for due diligence.
FAQ
Quick homeowner answers.
How should I compare ADU builders in the Bay Area?
Compare ADU builders by city experience, drawings and permit support, ADU type fit, utility/site work assumptions, budget clarity, and whether the proposal clearly separates design, permits, construction, and exclusions.
Should I talk to builders before I have ADU plans?
Yes, but do not treat early numbers as final bids. Without feasibility and drawings, a builder is usually pricing assumptions.
Can one company handle drawings, permits, and construction?
Some design-build ADU providers can coordinate the full path. Verify which parts are in-house, which are outsourced, and who is responsible for corrections during city review.