ADUs & Room Additions
Accessory Dwelling Units and room additions are powerful ways to boost property value, accommodate growing families, or generate rental income. Our process starts with zoning and design feasibility, confirming setbacks, height limits, and utility connections, then crafting plans that integrate seamlessly with your existing structure and neighborhood character.
Once permits are secured, we construct new foundations or reinforce existing footings, frame walls, and tie into your home's electrical, plumbing, and HVAC systems. We manage insulation, drywall, roofing, and exterior siding to match your primary residence, ensuring the addition feels like a natural extension rather than an afterthought.
The interior build-out focuses on livability and style. Whether you need a self-contained studio with full kitchen and bath, or a spacious new master suite, we install durable floors, energy-efficient windows, custom millwork, and lighting solutions that maximize comfort and appeal. The result is extra square footage that enhances your daily life or adds a lucrative revenue stream.
Accessory dwelling units are one of the smartest investments a San Diego homeowner can make, and Construction Crafters builds them end to end: detached ADUs, garage and basement conversions, junior ADUs, and room additions. We design to California's ADU laws and San Diego's accessory dwelling unit program so your project qualifies for the streamlined approvals it is entitled to.
ADU, junior ADU, or addition?
They solve different problems. Rental income points one way, more room for your own household points another. We price two options side by side so you compare real numbers instead of guessing.
| Question | Junior ADU | Attached ADU | Detached ADU | Room addition |
|---|---|---|---|---|
| Sits inside the existing house | Yes | No | No | No |
| Adds a separate entrance | Yes | Yes | Yes | Usually no |
| Own kitchen and bathroom | Kitchenette | Yes | Yes | Optional |
| Can be rented separately | Yes | Yes | Yes | No |
| Uses garden space | No | Some | Yes | Some |
| Typical San Diego range | $110k to $180k | $200k to $320k | $250k to $450k+ | $350 to $600/sqft |
What our ADU & room addition service includes
- Detached ADUs, attached ADUs, and junior ADUs (JADUs)
- Room additions and second-story expansions
- Design that meets California and San Diego ADU regulations
- Utility connections, setbacks, and parking solutions
- Permitting through plan check to final occupancy
Our process, step by step
- 01
Feasibility check
We confirm what your lot allows: unit size, setbacks, utility routing, and whether you qualify for San Diego's streamlined ADU review or bonus programs.
- 02
Design for approval
Plans are drawn to California ADU law and San Diego's ADU regulations from the start, which is what keeps plan check short.
- 03
Permits
We submit, track plan check, and resolve corrections until the permit issues.
- 04
Construction
Foundation to finishes under one crew and one schedule, including utility connections and any required fire separation.
- 05
Final occupancy
We pass final inspections and hand over a legal, rentable unit with documentation that protects its appraised value.
Typical price ranges in San Diego
ADU costs in San Diego depend mostly on whether you are building new or converting existing space. Typical 2026 ranges:
Garage-conversion ADU
$110,000 - $180,000
Junior ADU (within the home)
$80,000 - $150,000
Attached ADU
$200,000 - $320,000
Detached new-build ADU
$250,000 - $450,000+
Room additions
$90,000 - $250,000
Free Utility upgrades, sloped lots, and high-end finishes move projects up within these ranges. We give you a fixed, itemized proposal after a feasibility visit.
Serving San Diego County
- Point Loma
- Ocean Beach
- Pacific Beach
- La Jolla
- Del Mar
- Solana Beach
- Encinitas
- Carlsbad
- Oceanside
- Coronado
- Imperial Beach
- North Park
- Hillcrest
- Clairemont
- University City
- Mission Valley
- Carmel Valley
- Scripps Ranch
- Rancho Bernardo
- Poway
- San Marcos
- Vista
- Escondido
- Santee
- Lakeside
- El Cajon
- La Mesa
- Spring Valley
- Lemon Grove
- National City
- Chula Vista
- Bonita
Frequently asked questions
How much does an ADU cost in San Diego?
Garage-conversion ADUs typically run $110,000 to $180,000, attached ADUs $200,000 to $320,000, and detached new builds $250,000 to $450,000 or more depending on size, finishes, and utility work. We price each project from your lot and goals after a site visit.
Do I need a permit to build an ADU?
Yes, ADUs require permits, but California and San Diego have streamlined the process and limited how cities can restrict them. We manage the full submittal and approval so you benefit from the faster ADU review path.
How long does it take to build an ADU?
Plan on roughly 3 to 5 months of construction after permits, plus design and plan-check time before that. Garage conversions are usually faster than ground-up detached units.
What size ADU can I build?
Detached ADUs of up to 1,200 square feet are allowed on most San Diego single-family lots, and state law protects your right to at least an 800 square foot unit on nearly any lot. We confirm your exact allowance during feasibility.
Can I have both an ADU and a junior ADU?
On most single-family lots in San Diego, yes: one ADU plus one JADU carved out of the main home. It is one of the most cost-effective ways to add two rental units to a single property.
Do I need my own architect for an ADU?
No. We coordinate the design and structural engineering in-house as part of the project, drawn to San Diego's ADU standards from the start so plan check stays short. If you already have plans, we can price and build from those instead.
Does an ADU need its own address and utilities?
ADUs receive their own address for mail and deliveries, and utilities can usually share the main house connections rather than requiring new meters. Separate metering is optional; we walk you through the cost trade-offs during feasibility.
Will an ADU add value to my property?
A permitted ADU adds livable square footage and rental potential, both of which appraisers and buyers recognize. Keeping the unit fully permitted is what protects that value at resale.
Tell us the goal.
Free, itemized, and based on a real visit to your property. We reply within 2 to 3 business days.