ADU Builder in Pasadena, CA

We build accessory dwelling units in Pasadena and the San Gabriel Valley, and most of the work we do is garage conversions, junior ADUs and above-garage units rather than ground-up detached construction. That is deliberate. On the majority of Pasadena lots, converting existing structure is faster to permit, less expensive to build, and legally allowed to be larger than a new detached unit.

We are a licensed Class B General Building contractor, CSLB #992200, active and bonded, and we have been building in Pasadena since 1998. You can verify that at cslb.ca.gov before you call us, and we would suggest you check it for every ADU company you talk to. A number of the firms advertising ADUs in this market are sales organizations that subcontract the actual construction.

WHY A CONVERSION USUALLY BEATS NEW CONSTRUCTION IN PASADENA

No size cap. Pasadena's code sets no maximum size for a converted ADU. A newly constructed detached ADU is capped at the lesser of 800 square feet, or 1,200 square feet on lots of 10,000 square feet or more, or 50 percent of the floor area of the primary dwelling. That last clause is the one that catches people: on a 1,400 square foot bungalow, the 50 percent test caps a new unit at 700 square feet no matter how big the lot is. A large detached garage can legally convert to more square footage than you would be allowed to build new.

No replacement parking. Under California Government Code section 66322, a local agency cannot impose parking requirements on an ADU created within an existing primary residence or an existing accessory structure, or on an ADU within one-half mile walking distance of public transit. If you are converting a garage, you generally do not have to replace the parking you are giving up.

Allowed where new construction is not. Pasadena prohibits newly constructed ADUs in Hillside Overlay districts, but that prohibition does not extend to conversions. In landmark and historic districts, converted ADUs such as a detached garage conversion are permitted, while new attached and detached units are permitted only where not visible from the public right-of-way.

Shorter timeline, smaller disruption. No foundation, no new roof structure, and far less site work. The building is already there.

WHAT WE BUILD

Garage conversion ADU. Converting an existing detached or attached garage into a full independent unit with its own kitchen, bathroom and entrance. This is the bulk of what we do.

Junior ADU, or JADU. Up to 500 square feet created within the walls of the existing house, with an efficiency kitchen. It can share a bathroom with the main house. The least expensive route to a legal second unit.

Above-garage unit. Adds living space without consuming yard, and a common fit on Pasadena's deeper lots.

Interior conversion. Converting an attached portion of the house or an existing rear structure into a permitted unit.

Legalizing an existing unpermitted conversion. Common in Pasadena and Altadena, and often achievable.

We also build attached and detached new-construction ADUs. Those are longer projects with more site work. We are happy to talk through whether one makes sense on your lot, but we will usually show you the conversion math first.

WHAT IT COSTS

A full garage conversion to an accessory dwelling unit commonly runs $120,000 to $150,000 in the Los Angeles market. On top of construction, budget roughly $8,000 to $20,000 for design and plans, and $5,000 to $20,000 for permits and city fees before Pasadena's reductions are applied. Converting a garage to habitable space without a kitchen or full bathroom costs meaningfully less, but it is not an ADU and it does not carry the same value or rental potential. A JADU is typically the lowest-cost option of all, because it uses existing plumbing and electrical runs.

These are planning ranges from published Los Angeles market pricing, not a quote. We price after a site visit and give you a written, itemized proposal with stated allowances and exclusions.

FEE REDUCTIONS WORTH DESIGNING AROUND

Pasadena has adopted ADU fee reductions that are not widely advertised: a 50 percent reduction in plan check fees, a 25 percent reduction in permit fees for ADUs up to 900 square feet, and an exemption from the city's Residential Impact Fee at that same size. Separately, California Government Code section 66311.5 exempts an ADU of 750 square feet or less of interior livable space from impact fees.

Those two numbers, 750 and 900, are hard thresholds. Designing a 780 square foot unit instead of a 750 square foot unit can cost real money for thirty square feet. We look at that before drawing anything.

WHERE THE CODE IS IN FLUX

The state Department of Housing and Community Development formally notified Pasadena on February 26, 2025 that parts of the city's ADU ordinance were out of compliance with state law, including its parking requirement on state-exemption ADUs. The city has been responding, which means the specific numbers in the local ordinance are a moving target. We confirm current adopted standards with the Planning Division on every project rather than working from a version of the code that may have changed.

LEGALIZING AN UNPERMITTED CONVERSION

This comes up constantly. It is often possible. It typically requires opening walls so an inspector can verify framing, insulation and wiring, then correcting whatever is deficient. Whether legalizing or rebuilding is the better economics depends on how the original work was done. An unpermitted unit creates problems at sale, at appraisal, at refinance, and with homeowners insurance, so it is worth resolving.

HOW THE PROJECT RUNS

Feasibility first: your lot, your zoning, whether you are in a Hillside Overlay or a landmark district, where your utilities run, and which size rule actually binds on your property. Then design and plans, including the structural, electrical, plumbing and Title 24 documents the city requires. Then permitting, which we submit and manage through plan check corrections. Then construction, inspections, and final sign-off. The unit is not legal until that final inspection is signed.

HOW TO CHECK THAT WE ARE LICENSED

Go to cslb.ca.gov, choose Check a License, and enter 992200. Under California law your down payment on a home improvement contract is capped at the lesser of $1,000 or 10 percent of the contract price. Any contractor asking for more than that at signing is not following the law.

Call (626) 744-0402 for a free on-site feasibility visit. We serve Pasadena, Altadena, South Pasadena, San Marino, Arcadia, Sierra Madre, La Canada Flintridge, Glendale, Temple City, San Gabriel, Alhambra, Monrovia, Eagle Rock and Duarte. Altadena is unincorporated Los Angeles County, so permits there come from the county rather than the City of Pasadena, and the rules and fee schedules differ.