ADU builder in San Diego, from first sketch to move-in
Detached ADUs, garage conversions, attached units and JADUs. We draw the plans, get the City of San Diego permit and build it, so you deal with one licensed team the whole way.
What does an ADU cost in San Diego?
These are realistic 2026 ranges for San Diego. Size, site work, utility runs and finishes decide where your project lands. New construction generally runs about $250–$450 per square foot.
Junior ADU (JADU)
A unit of up to 500 sq ft carved out of your existing home, with its own entrance and efficiency kitchen.
Garage conversion
Your existing garage becomes a legal living unit. The slab, walls and roof are already there, which keeps cost down.
Attached ADU / addition
New living space joined to the main house, sharing a wall and often the utilities.
Detached ADU
A stand-alone backyard home. Example: a 600 sq ft unit typically lands between $150k and $270k.
Typical 2026 San Diego ranges, not a quote. You get an itemized, fixed price after a free site visit. Read the full San Diego ADU cost guide
ADU constructionEverything an ADU needs, under one contract
Most ADU delays come from the hand-off between a designer, a permit runner and a builder. We keep all three in one team, so the plans we submit are the plans we build.
Feasibility & site review
We check setbacks, utilities, sewer lateral and fire access on your lot before anything is drawn.
Design & permit set
Floor plans, elevations, structural and Title 24 drawings prepared for the City of San Diego or County review.
Construction & inspections
Foundation to final: framing, MEP, finishes and every city inspection, run by one project manager.
Rental-ready finishes
Durable kitchens, baths and flooring chosen for tenants or family, plus mini-split HVAC and separate metering where needed.
How your project runs
One project manager from the first visit to the final walkthrough.
Free site visit
1 weekWe walk the lot, talk goals and budget, and tell you which ADU type fits.
Design & permits
2–4 monthsPlans drawn, submitted and taken through city review.
Construction
3–6 monthsBuild, inspections and weekly updates from your project manager.
Final & move-in
1–2 weeksFinal inspection, certificate and a walkthrough before handover.
Projects from our San Diego portfolio
What San Diego clients say
Before finding XLNC Builder, another company left me with headaches and plans the city rejected. From day one XLNC was professional and knowledgeable, walked me through the entire process, and their pricing was very reasonable.
They fit every feature we wanted into the footprint while keeping us within San Diego's strict zoning limits, and turned our rough ideas into a technically perfect permit set.
XLNC Builder, with Nancy and her dedicated, professional team, has been a reliable guide across my construction projects. I'm fortunate to count on them.
Licensed, bonded and insured. Verify CSLB license #1153455
ADU Construction: frequently asked questions
Areas we serve
Based in Mira Mesa (9400 Activity Rd), we work across San Diego County, including:
- Mira Mesa
- Scripps Ranch
- Rancho Bernardo
- 4S Ranch
- Poway
- Carmel Valley
- La Jolla
- Del Mar
- Clairemont
- North Park
- Point Loma
- Tierrasanta
- Encinitas
- Carlsbad
- Escondido
- Coronado
- Chula Vista
Tell us about your project
We reply within one business day to set up a free site visit. No pressure, no hidden fees.
Itemized, fixed quote
Every line priced before work starts.
Plans, permits and build in one team
One project manager, start to finish.
Licensed, bonded & insured
CSLB #1153455, Class B General Building.
Get your free ADU quote
Takes 30 seconds. Fields marked * are required.