Room additions & ADUs in San Diego, CA
Room additions, second stories, ADUs, garage conversions, and whole-home remodels. We handle design, structural engineering, permits, and the full build.
Best home additions in San Diego, CA
We build room additions, ADUs, and whole-home remodels across San Diego and San Diego County. From a single-room bump-out to a detached ADU or a full second story, we handle the design, structural engineering, permitting, and construction with our in-house crew. Most additions run 3 to 6 months from permit to final inspection.
What's included in home additions in San Diego
Room additions & bump-outs in San Diego
Adding square footage for a bedroom, family room, or larger kitchen. We handle the foundation, framing, roof tie-in, and finishes.
ADUs & granny flats in San Diego
Detached and attached accessory dwelling units under California's ADU laws, from studio casitas to two-bedroom units, permitted and built to code.
Garage conversions in San Diego
Turning an attached garage into a bedroom, office, gym, or ADU with proper insulation, egress, and HVAC.
Second-story additions in San Diego
Building up when you cannot build out. Structural engineering, a new staircase, and a roof line that matches the existing home.
Basement & attic conversions in San Diego
Finishing usable square footage you already have, with insulation, egress, and code-compliant ceiling heights.
Whole-home remodels in San Diego
Taking a dated home down to the studs and rebuilding kitchens, baths, flooring, and layout in one coordinated project.
See related serviceHow to start your San Diego home additions
- 1
Free in-home estimate
We come to your home, walk the space, and listen to what you want out of the home addition. No high-pressure sales, no surprise fees later.
- 2
Honest, written quote
You get a clear line-item quote in plain English. Materials, labor, timeline. If something changes mid-project, you sign off before any extra cost.
- 3
Design and material selection
We help you pick finishes that fit your budget and the existing home. We have trade pricing with local suppliers, which we pass through.
- 4
Build with our in-house crew
The Carrasco family runs the job site every day. No revolving subcontractors. Clean work, daily progress, and someone you can talk to face-to-face.
- 5
Final walkthrough and warranty
We do a punch-list walk with you before final payment. If anything isn't right, we fix it. Our workmanship is backed for a full year after completion.
How much does a room addition or ADU cost in San Diego?
A room addition in San Diego runs $40,000 to $100,000 depending on size and whether it includes a bathroom. Garage conversions run $60,000 to $120,000. Detached ADUs run $150,000 to $300,000 depending on size and finishes. Whole-home gut remodels run $100,000 to $250,000. Every project gets a written, line-item quote after the design phase.
Why San Diego homeowners choose 5 IN 1 for home additions
Home Additions in 10 San Diego neighborhoods
San Diego City is the densest, most varied building landscape we work in. 1920s Craftsman bungalows in Mission Hills, mid-century homes in Clairemont and Linda Vista, modernist Eichlers in San Carlos, and 1970s-90s tract homes in Mira Mesa and Bay Park. Permits go through the City of San Diego, which adds time but is straightforward once you know the inspectors.
We have remodeled San Diego homes since 1987. The Carrasco family runs every job site, the same in-house crew handles your project from rough-in to final walk, and we pull every permit in your name.
San Diego neighborhoods we serve
- • Mission Hills
- • Hillcrest
- • North Park
- • South Park
- • Pacific Beach
- • Clairemont
- • Mira Mesa
- • Bay Park
- • Linda Vista
- • Point Loma
ZIP codes: 92101, 92102, 92103, 92104, 92105, 92107, 92108, 92109, 92110, 92111, 92113, 92114, 92116, 92117, 92118, 92119, 92120, 92122, 92123, 92124
Recent home additions projects in San Diego
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Home Additions in San Diego: frequently asked questions
How much does a room addition or ADU cost in San Diego?+
In San Diego, room additions run $40,000 to $100,000, garage conversions $60,000 to $120,000, and detached ADUs $150,000 to $300,000. Whole-home gut remodels run $100,000 to $250,000. You get a written line-item quote after the design phase.
How long does a room addition or ADU take?+
Plan for 3 to 6 months from permit to final inspection for most additions and ADUs. Design and permitting adds 2 to 4 months before construction starts, and City of San Diego review runs longer than the smaller cities.
Do I need a permit for an addition or ADU in San Diego?+
Yes. Every addition and ADU in San Diego needs a permit and plan check. We handle the drawings, structural engineering, and the submittal in your name, and we meet inspectors at each stage.
Can I build an ADU on my San Diego lot?+
Most single-family and multi-family lots in San Diego qualify for at least one ADU under current California law, and many also allow a junior ADU. We check your lot, setbacks, and utilities up front and tell you what will actually fit.
What additions add the most value in San Diego?+
In San Diego, ADUs top the list because of the rental income and the region's housing demand. Primary-suite additions and garage conversions to living space also return well. We can talk through the numbers for your specific block.
Other remodeling services in San Diego
Kitchen Remodeling in San Diego
Full kitchen remodels with cabinets, countertops, flooring, and layout changes. We handle the whole job in-house, from rough-in to final walkthrough.
Bathroom Remodeling in San Diego
Walk-in showers, tubs, vanities, and tile. We handle plumbing, electrical, framing, and finish work in-house.
Flooring in San Diego
Luxury vinyl plank, tile, hardwood, and laminate. Single rooms or whole-home installs.
Home Additions near you in San Diego County
Ready to start your San Diego home additions project?
Free in-home estimate. Honest pricing. Written quote within 48 hours.