Backyard before ADU construction in Brentwood
Completed backyard project in Brentwood
Before
After
adu builder brentwood

ADU builder
Brentwood.

ADU construction in Brentwood runs through LADBS — hillside engineering, retaining walls, and tight haul routes. We handle garage conversions, detached units, structural plans, permits, and certificate of occupancy.

$115k–$185kgarage conversion
16–24 weekstypical build
8–12 weekspermit review
Bonded & Insured$2M Liability
Transparent PricingLine-item quotes
Licensed TechsPool, equipment, and startup care
5 / 5 Stars187 Google reviews
Local Conditions

ADU work in
Brentwood.

Brentwood ADUs often involve larger budgets, hillside constraints, and careful neighbor coordination. Foundations, garage slab reinforcement, and utility trenching have to account for hillside transitions, canyon drainage, and estate lots north of Sunset. Plan check runs through LADBS with Title 24 energy compliance and structural review on every permitted unit. Garage conversions often move faster than detached new-builds because the shell exists; hillside lots, tight side yards, and long utility runs can still add foundation and MEP cost. Most ADU construction in Brentwood lands in the $125,000-$360,000 range — garage conversions from $115k–$185k, detached units from $250k–$390k. Permit fees, utility connections, soils reports, and design are quoted separately by line item. Finish level, fire sprinklers, and separate utility meters are the usual cost drivers after site conditions. Mandeville Canyon and Kenter Canyon require access and slope planning. We coordinate HOA/ARC packets — exterior materials, parking replacement, access plans — in parallel with city submittals when they apply. We already build in your backyard. Here's what we handle for Brentwood homeowners.

01

Permits and inspections

LADBS handles ADU plan check, structural review, and certificate of occupancy. Typical plan check: 8–12 weeks.

02

HOA and access

Mandeville Canyon and Kenter Canyon require access and slope planning. That drives how we stage garage conversions, utility trenching, and detached ADU placement.

03

Soil and foundation

hillside transitions, canyon drainage, and estate lots north of Sunset affects foundation depth, garage slab reinforcement, and utility routing for detached units.

04

Pricing in Brentwood

Most ADU projects here land $125,000-$360,000 — garage conversions from $115k–$185k, detached units from $250k–$390k.

Pool + ADU

Also a pool builder in
Brentwood.

We build pools and ADUs on the same lots across Southern California. When both are planned together, shared excavation, grading, and utility trenching often saves 10–15% versus separate projects.

Pool builder in Brentwood ADU construction overview

Nearby Cities

Also serving
nearby areas.

View nearby cities
Brentwood ADU service area
Common Questions

Brentwood
ADU FAQ.

How much does an ADU cost in Brentwood?
Most ADU construction in Brentwood runs $125,000-$360,000 depending on type and finish level. Garage conversions typically start $115k–$185k; detached new-build units $250k–$390k. Permit fees, utility connections, and soils work are quoted separately.
Who handles ADU permits in Brentwood?
ADU permits in Brentwood run through LADBS. Plan check typically takes 8–12 weeks. We prepare structural plans, Title 24 energy calcs, and submittals; you sign what the city requires.
Can I build an ADU and a pool on the same lot in Brentwood?
Usually yes. Pools and ADUs have separate setback and lot-coverage rules. When both are planned together, shared excavation, grading, and utility trenching often saves 10–15% versus separate projects.
Do Brentwood ADU projects need HOA approval?
Mandeville Canyon and Kenter Canyon require access and slope planning Most Brentwood ADU projects still need careful staging and neighbor-sensitive access planning even without formal HOA review. We price that on the first site walk.
Free ADU consult

Let's scope your ADU in Brentwood.

Share the address, ADU type, and rough budget. We reply within one business day with a time for a free phone consult — feasibility, setbacks, and a real project range, not a teaser price.

By submitting, you agree to our privacy policy. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
  • Free phone consult — lot feasibility in 1 business day
  • Floor plan direction & project range in 5 days
  • No deposit until contract signed
  • Honest "no" if the lot doesn't pencil
Call us directly
(747) 293-9482
Call Get a quote