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ADUs & Additions

ADU Builder & Room
Additions in San Diego

Backyard units, garage conversions, junior ADUs and room additions that create living space, a rental, or a home for family on the lot you already own.

Explore an ADU
Completed two-story ADU with a stucco exterior
More Room, Same Address

Grow without
moving

California has spent years making accessory dwelling units easier to build, and San Diego homeowners have noticed. An ADU can house a parent, give a grown child a place of their own, or bring in rent, typically somewhere between $1,500 and $3,000 or more a month depending on the size of the unit and the neighborhood.

We build every common type: detached backyard units, conversions of existing garages, attached ADUs, and junior ADUs carved out of space inside the house. When the goal is more room for the people already living there, a room addition is often the better fit, and we build those too, from single-room bump-outs to full second stories.

Each project starts with the realities of your property: setbacks, utilities, access for construction and the rules of your city or the county. From there we take care of design coordination, permits, construction and the final inspection.

01
What We Build

ADUs, garage conversions
and second stories

  • Detached backyard ADUs
  • Garage-to-ADU conversions
  • Attached ADUs
  • Junior ADUs within the home
  • Single-story room additions
  • Second-story additions
  • Primary suites and family rooms
  • Utility connections and metering
ADU under construction at the sheathing stage with scaffolding
02
State ADU Rules

What the law
now allows

State law sets a floor that cities can't go below. A single-family lot can generally have one ADU plus one junior ADU, a junior ADU can be up to 500 square feet inside the existing home, and ADUs under 750 square feet are exempt from development impact fees. Those rules are a big part of why smaller units are often the best value.

Local rules still matter. The City of San Diego, the County and the neighboring cities each set their own standards for height, design and placement within the state's limits, and coastal properties can need an extra layer of approval. Plan review usually takes four to eight weeks before construction, and the build itself typically runs three to six months.

Garage interior before its conversion into an ADU
03
Fixed-Price Plans

Prefer a plan
that's already drawn?

Some homeowners would rather choose a proven design than start from a blank page. Chris also builds for Creative Adu, a sister brand offering three pre-designed ADUs: a 500-square-foot studio, a 750-square-foot one-bedroom and a 1,200-square-foot two-bedroom, each with a fixed-price written scope after the site walk.

If a custom design suits your property better, or you need an addition rather than a separate unit, we design around your lot instead. Demand for second units is especially strong in La Mesa, Spring Valley, Encinitas and North Park, where lot sizes and local rules make them practical.

Room addition with large sliding glass doors
ADUs & Additions

Second units, explained

What is the typical price of an ADU in San Diego?

Typically somewhere between $150,000 and $400,000 or more. Converting a garage tends to be the cheapest route, since the shell is already standing; detached, newly built units with high-end finishes sit at the top. Size, site work and utility runs account for most of the difference. We price your project once we've seen the property.

How long does an ADU take to build?

Most take six to twelve months in total. Plan review usually takes four to eight weeks and construction three to six months, depending on the type of unit and the site.

What is a junior ADU?

A junior ADU is a unit of up to 500 square feet created inside an existing single-family home, often from a bedroom or an attached garage. It can have its own entrance and an efficiency kitchen, and it's usually the least expensive way to add a second living space because no new structure is needed.

Should I build a room addition or an ADU?

It depends on who the space is for. If it's for people already living in the house, an addition connects to everything you have. If it's for a tenant, a parent who wants independence or future rental income, a separate ADU with its own kitchen and entrance usually makes more sense. We'll talk through both.

Do ADUs and additions need permits?

Yes, every ADU needs a building permit, and room additions do too. Our team draws up the plans, shepherds them through review and books the inspections, so you never have to visit the permit office.

Related

ADUs around the county

La Mesa ADUs

Lots near the trolley, where state parking rules can work in your favor.

See La Mesa
Spring Valley Second Units

Bigger mid-century lots, permitted through the County.

See Spring Valley
Creative Adu Plans

Three pre-designed units, from a studio to a two-bedroom, with fixed pricing.

Visit Creative Adu
Thinking About an ADU?

Find out what
your lot can hold

Share your address and the space you have in mind. We'll review the property, explain your options and put a written price together after visiting.

Ask About My Lot (619) 971–1354
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