Home Additions
More room, built right.
Room additions and second stories expand your home without the cost and hassle of moving. We engineer the structure, produce the plans, pull the permits, and build — one accountable team start to finish.
What's included
- —Room & second-story additions
- —Structural engineering in-house
- —Foundation & soils assessment
- —Architectural plans & permitting
- —Seamless tie-in to existing home
The details
What to expect, what it costs, and how the permits and structure get handled.
Adding on instead of moving out
When a home stops fitting your life, an addition is often cheaper and far less disruptive than buying and moving in San Diego's market. A room addition, a primary suite, or a second story buys you the space you actually need while keeping the location, the schools, and the equity you already have.
We engineer the structure, produce the architectural plans, pull the permits, and build — one accountable team from the first sketch to the final tie-in. New foundations, framing, and connections to the existing house all get designed in-house, which keeps the project moving and the details consistent.
What it costs and how long it takes
Ground-floor additions in San Diego commonly run somewhere around $200–$400 per square foot depending on finishes and complexity, so a modest room addition often lands in the $60,000–$150,000 range. Building up — a second-story addition — typically costs more per foot than building out, because of the structural work, the temporary weather protection, and the disruption to the floor below.
Most additions run about three to six months of construction, with design and permitting adding time before that. We give you a realistic schedule and a fixed scope up front, so you're planning around real dates, not guesses.
Engineering, soils, and property taxes
Additions almost always need structural engineering — new loads, new foundations, and the connection back to the existing structure all require stamped plans, which we produce in-house. On lots with fill or expansive soil, or anything on a slope, a soils report may be required before the foundation can be designed; we'll tell you up front whether yours needs one.
On taxes, an addition doesn't reset your whole assessment. Under Prop 13, only the new square footage is reassessed at current value and added to your existing base, so the bulk of your home keeps the basis it already has.
Goes hand-in-hand with
Projects our clients usually pair with this one.
You'll also need
The plans and permits this work typically requires — handled in-house, so nothing stalls.
Common questions
- How much does a home addition cost in San Diego?
- Ground-floor additions commonly run about $200–$400 per square foot, so a modest room addition often lands around $60,000–$150,000. Second-story additions cost more per foot because of the added structural work. We give a fixed written estimate after assessing your home and lot.
- Do home additions need engineering?
- Almost always. New loads, new foundations, and the tie-in to your existing house all require stamped structural plans. We produce that engineering in-house alongside the architectural drawings, so the structure and the build stay coordinated under one team.
- Will an addition trigger a full property reassessment?
- No. Under California's Prop 13, only the new square footage is reassessed at current market value and added to your existing base — the rest of your home keeps the assessment it already has. You'll receive a supplemental bill for just the added value.
- Is it better to add on or move?
- It depends, but in San Diego's market an addition often costs less than buying up and skips the moving, the new mortgage, and leaving your neighborhood. If the location works and the lot allows it, building the space you need is usually the better value.
Get your home additions estimate
Real numbers from the team that does the work — permits and engineering handled in-house. No obligation.
Home additionsNo obligation. We'll never share your details.