Room Additions & ADUs in San Diego
Expand your living space with a permitted addition or build a standalone ADU. We handle design, engineering, permits, and construction.
What It Costs and Why
Room Addition
$200 – $400/sq ft
ADU
$120K – $250K+
Timeline
2 – 4 Months
Top Cost Drivers
- •Size and type of addition
- •Foundation requirements
- •Whether plumbing/kitchen is included
- •Utility connections (especially ADUs)
- •Site access and grading
- •Structural engineering needs
Room Additions
A room addition extends your existing home, adding square footage for a new bedroom, expanded living area, home office, or master suite. The new space integrates with your existing structure and systems.
We handle the full scope: architectural design, structural engineering, foundation work, framing, roofline integration, and all interior finishes. The goal is a seamless addition that looks like it was always part of the home.
Common Addition Types
- •Master suite additions
- •Great room / living space expansion
- •Home office or studio
- •Second-story additions
- •Garage conversions
ADU Construction
An Accessory Dwelling Unit is a self-contained living space on your property, with its own kitchen, bathroom, entrance, and utilities. California law has streamlined ADU permitting, making it one of the most practical ways to add living space or rental income.
We build detached ADUs, attached ADUs, and garage conversions. Each project includes full design, engineering, permit handling, and construction.
ADU Considerations in San Diego
- •Most single-family lots qualify for at least one ADU
- •No owner-occupancy requirement (state law)
- •Utility connections can be a significant cost factor
- •Setback and height requirements vary by zone
- •Coastal overlay zones have additional review steps
Frequently Asked Questions
Room additions in San Diego typically cost $200 to $400 per square foot, depending on the type of space (bedroom, bathroom, living area), structural complexity, and finish level. A 400 sq ft addition might range from $80,000 to $160,000.
ADU construction in San Diego ranges from $120,000 to $250,000+ depending on size, site conditions, and finish level. Detached ADUs typically cost more than garage conversions. California law streamlines ADU permitting, but site-specific factors like utility connections and access can affect cost.
Yes. Room additions and ADUs require building permits from the City of San Diego. ADU permits follow California state guidelines (AB 68, SB 13) which streamline the process. We handle all permit applications, plan submissions, and inspector coordination.
Most room additions take 2 to 4 months of construction time. Design and permitting add 6 to 12 weeks before that. ADUs follow a similar timeline. Projects requiring foundation work on San Diego's common slab-on-grade homes may take longer.
In most cases, yes, but second-story additions require structural engineering analysis, may be subject to height restrictions in certain neighborhoods, and typically cost more than ground-level additions due to foundation reinforcement requirements. Coastal overlay zones (La Jolla, Del Mar) have additional review requirements.
A room addition expands your existing home. It shares walls, systems, and entry points. An ADU (Accessory Dwelling Unit) is a separate, self-contained living space with its own kitchen, bathroom, and entrance. ADUs can be attached or detached and have their own permitting pathway under California law.
Ready to Expand Your Home?
Schedule a free consultation. We'll assess your property, discuss what's possible, and give you realistic numbers.