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DESIGN of Accessory Dwelling Units "ADU's"

We design custom "ADU's" that are easy to read, clear, and concise. They are updated with the California Building Regulations and are compliant with Energy Code Title 24 requirements.

What is an Accessory Dwelling Unit (ADU)

An ADU is an independently habitable dwelling that provides shelter, heating, cooking facilities, and sanitation facilities for no more than one family. 
Some common names for ADU's include converted garages, room addition, backyard house, mother-in-law flat, and more. An ADU is technically any secondary unit that can be legally converted or added either on the same property or as part of the house.




















ADU Types

ADU's go by many names, but they all serve the same function—to provide extra living space.  ADU types can be generally broken down into three main categories: internal, attached, or detached additions to a house.

  • Internal ADU's

These are existing portions of homes that are transitioned to accommodate an extra person or two.  Common internal ADUs are converted garages, basements, or even attics. These ADU conversions are the least costly as they require the least amount of construction.  The price starts to increase when you want to add an extra bathroom or closet, however, useful additions can make an ADU a more attractive to potential rentals.

  • Attached ADU's

Attached ADUs are typically newly constructed rooms attached to the primary home. Attached ADUs, also known as addition ADUs or ‘bump-out ADUs’, People add a room (and usually a bathroom) so an extra individual could live inside the house. Attached ADUs sometimes have their own entrance, so people living there have an extra sense of privacy and increased ease of access. 

  • Detached ADU's

The detached ADU is a private and extremely functional stand-alone structure.  If you have the yard space, they can be utilized for a variety reasons. Because of their flexibility, the detached additions are the most sought-after type of ADU. This is especially true if you are considering extra rental income.  Detached ADUs are extremely attractive to tenants because they are essentially tiny homes, usually boasting a small kitchen, bathroom, and a lounge area.

ADU Types

The housing plans for Accessory Dwelling Units are just as involving as any other form of construction. Since most of them are simply built from wood, do not assume that they do not require expert intervention. The mechanical system, plumbing system, and lighting system have to be done just like the normal houses.

ADU Fact Sheet
Do I need City approval for a new ADU?
Yes. An ADU application is required, in addition to a building permit. The ADU application (available at the City Office) helps the City ensure the ADU will comply with the ADU requirements. The building permit application will need to show key features of the proposed ADU, such as egress, fire separation, locations of utility shutoffs, entrances, windows, parking, etc. The City’s Building Official will need to verify that these features are provided and that the structure complies with applicable Building Code requirements on-site before use of the ADU can be approved.
I already have what I call an “ADU”. Do I need to seek City approval for what I already have?
Yes. A permit and approval from the City are necessary in order to ensure that occupied dwelling units are safe and comply with Building Code requirements and the ADU rules adopted by the City Council. An ADU is legal only with an established building permit and approved ADU application. If the City becomes aware of an unpermitted ADU, the City may compel the owner to cease using the dwelling unit, utilizing those remedies available per Municipal Code.
Where can I build an ADU?
ADUs are allowed as accessory uses in all residential zones (R-1, R-2, and R-3 Zones), as well as the C-2 Commercial-Residential Zone, if in compliance with all of the development standards (such as setbacks, size, appearance, parking, etc.).
In addition to the primary dwelling, how many ADUs can I build on a single lot?
Only one (1) ADU is allowed per lot of record. However, if a lot happens to have two legal, detached (primary) single-family dwellings, each of those dwellings may have its own ADU, per State law.
Are property owners required to live in the primary dwelling or the ADU?
No. There is not an “owner occupancy requirement” for ADUs.
Are there size limitations for an ADU?
Yes. An ADU can be no larger than 900 square feet. However, if an attached ADU (“accessory suite”) occupies the entire basement of a home, then it can be up to 1200 square feet. There is no minimum size for an ADU. The maximum height for an ADU is the same as that for any other dwelling allowed in the zone.
Is off-street parking required for an ADU?
Yes. A minimum of one off-street parking space shall be provided for the ADU. This ADU parking shall be in addition to any required parking for the primary dwelling(s) and must meet the City’s parking standards.
Does an ADU need to be visually subordinate to the main dwelling?
Yes, detached ADUs must be sited at least 10 feet behind the front building line of any primary dwelling on the same lot, and entrances to attached ADUs must be different from those of the primary dwelling. Such entrance must also be located somewhere other than the front of the primary dwelling.
Are there design standards for ADUs?
ADUs that are separate or extend from the primary dwelling shall be architecturally compatible with the primary dwelling. This means that the ADU should match the appearance of the primary dwelling (i.e. be made of similar materials, and have a similar roof pitch, color, and finish materials).
What are the required setbacks for an ADU?
The minimum side and rear yard setbacks for a detached ADU shall be the same as for dwellings in the subject zone. However, if the ADU abuts an alley, the minimum rear yard setback is 5 feet.
Can I convert my existing accessory structure into an ADU?
An existing garage structure or other outbuilding may be converted to an ADU, provided that the structure complies with the setback standards for the primary structure as prescribed in the underlying zone, applicable building codes, and all other standards.
Does an ADU need to meet building and fire codes?
Because an ADU is a distinct dwelling unit, it must have its own utilities and shut-off access, except as the Building Code or Building Official may allow. The creation of an “accessory suite” (an attached ADU) must also have fire and sound separations as required by Building Code and/or Building Official.
Should I hire a professional to design my ADU?
A licensed general building contractor or architect  to assist in the design and development process, it is a good and trusty option.
How can I obtain additional information on ADUs? Senate Bill No.13

Design & Permitting

ADU Permit Process in California

No Matter How Big Your Project is 

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