ADU Builder in San Diego — Accessory Dwelling Units, Granny Flats & Garage Conversions

Troia Construction is San Diego's trusted ADU contractor. We handle every phase of your accessory dwelling unit project — from feasibility studies and ADU permit applications through construction and final inspection. Licensed general contractor CSLB #1151054.

San Diego ADU Experts

Design, Permit & Build Your ADU in San Diego

An accessory dwelling unit (ADU) — also known as a granny flat, casita, backyard cottage, or mother-in-law suite — is one of the smartest investments a San Diego homeowner can make. ADUs generate rental income, support multigenerational living, and significantly increase property value. Troia Construction manages every phase in-house so you get direct owner involvement alongside expert field execution.

  • Feasibility studies, lot optimization, and ADU cost modeling for your San Diego parcel
  • Full ADU permit management across all San Diego jurisdictions and coastal overlays
  • Turnkey design-build delivery with the owner present on site
  • AB 1033 compliant construction — sell your ADU separately as a condo
  • San Diego ADU fee waiver guidance to save $8,000–$30,000

Garage Conversion ADUs

Transform your existing garage into an efficient granny flat or rental suite. San Diego's most affordable ADU option — we retrofit structures with new foundations, insulation, plumbing, and finishes that feel purpose-built. No additional parking required for garage conversions under California state law.

Attached ADUs

Seamlessly extend your primary residence with a connected accessory dwelling unit that shares structure yet performs as an independent home. Up to 50% of your primary dwelling size. Ideal for multigenerational living and aging-in-place in San Diego.

Detached ADUs & Backyard Cottages

Build a private stand-alone casita, guest house, or backyard cottage up to 1,200 sq ft. Complete with separate utility metering, private entrance, and curated outdoor living. Four-foot side and rear setbacks apply for detached ADUs in San Diego.

Junior ADUs (JADUs)

Convert up to 500 sq ft within your existing home into a junior accessory dwelling unit. JADUs require no additional parking and can be built alongside a standard ADU on the same lot — maximizing your San Diego property's rental income potential.

Room Additions & Home Expansions

Add strategic square footage that unlocks multigenerational living, home offices, guest suites, or hybrid work zones. Our room additions flow with your existing floor plan and comply with San Diego zoning requirements.

San Diego ADU Regulations & Permitting Guide

Understanding San Diego ADU rules saves time and money. Here's what every homeowner should know before building an accessory dwelling unit in San Diego County.

ADU Size Limits

Detached ADUs: up to 1,200 sq ft. Attached ADUs: up to 50% of primary dwelling. Junior ADUs (JADUs): up to 500 sq ft within your existing home. San Diego allows both a standard ADU and a JADU on the same lot.

Setback Requirements

Detached ADUs require four-foot side and rear setbacks. Attached ADUs follow primary-structure standards. Garage conversions within existing footprints may have no additional setback requirements under state law.

Parking & Transit

No additional parking required if your property is within half a mile of public transit, within a historic district, or involves a garage conversion. San Diego's extensive transit network means most properties qualify.

ADU Permit Timeline

San Diego targets 60-day plan reviews for ADU applications. State law mandates a 15-business-day completeness check. Coastal zone projects may take longer. We shepherd every submittal and respond to plan check comments fast.

ADU Fee Waivers

San Diego County waives $8,000–$30,000 in impact and connection fees for qualifying ADU projects. We help homeowners identify and apply for every available fee reduction to keep your ADU cost as low as possible.

AB 1033 — Sell Your ADU

San Diego has adopted AB 1033, allowing ADUs to be sold separately as condominiums. We build AB 1033-compliant accessory dwelling units so you have the option to sell your ADU independently from your primary home.

Why San Diego Homeowners Choose Troia for ADU Construction

Owner-Operated ADU Builder

The owner is on every ADU job site. No layers of project managers or subcontracted oversight. You get direct access to the licensed general contractor responsible for your build — from the first site walk through final inspection.

Full-Service Design-Build

We handle ADU feasibility, architectural coordination, permit applications, construction, and final inspections. One contractor, one point of contact, one team from start to finish. No middleman markups on your San Diego ADU project.

Licensed & Insured

California Contractors State License Board #1151054. Every ADU project is backed by a licensed, insured professional. We navigate San Diego's complex ADU regulations, coastal overlays, and building codes so you don't have to.

ADU Construction Across San Diego County

We build accessory dwelling units throughout San Diego County. Whether you're in a coastal neighborhood or an inland community, Troia Construction has the local permitting expertise to get your ADU built right.

Coastal San Diego

La Jolla, Del Mar, Encinitas, Carlsbad & Oceanside

Coastal zone ADU construction requires specialized knowledge of California Coastal Commission requirements. We prepare supplemental coastal documentation, manage hearings, and engineer every detail for the marine environment.

Central San Diego

North Park, Hillcrest, Mission Hills, Kensington & Normal Heights

San Diego's urban neighborhoods are ideal for ADU rental income. Smaller lots, strong rental demand, and proximity to transit mean most properties qualify for relaxed parking requirements.

Greater San Diego

Chula Vista, Poway, Escondido, La Mesa, El Cajon & Santee

Larger lots in San Diego's suburban communities are perfect for detached ADUs and backyard cottages. We coordinate with local jurisdictions across the county to navigate varying municipal requirements.

Free ADU Consultation

Ready to build your San Diego ADU?

Get a free ADU feasibility assessment, cost estimate, and permit timeline from a licensed San Diego contractor. We'll walk your property, evaluate zoning, and deliver a clear roadmap for your accessory dwelling unit project.

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