Converting a Garage in California

Converting a Garage in California: What you need to know?

Everyone has a space in their house where they can get away from the hustle and bustle, and California homeowners may want to turn an old garage into a retreat or home theater.

Building code requirements for garages in California depend on the classification of the building. It is best to consult a trained professional before converting any garage into living quarters. There are many benefits to turning an unused garage into a place you can call your own such as having more livable space or extra storage.

Before starting any construction, it is vital to understand the building code requirements surrounding making a garage into living quarters.

Type A vs Type B Garages:

ype A vs Type B Garages:

The first step of this process is to determine if your garage falls under “Type A” or “Type B.” Type A garages are structures that have more than one-half of their height more than 10 feet from the grade plane. In contrast, Type B are those less than half of their size above 10 feet unless they are used only for parking vehicles. For example, if you live in California and have an attached garage with an unfinished room above it, chances are you have a Type B garage.

There are several different ways to go through the process of converting a type B garage into liv space. You can do so by making the entire garage into a livable space or by just making the conversion to an attached bedroom.

Making the Entire Garage into Living Space:

Making the Entire Garage into Living Space:

If you choose to make the entire garage into a living space, it is essential to know several California building code requirements that you must meet. The most critical codes that must be followed are those for habitable rooms. Habitable rooms must have a window and a door that opens and closes independently and a working smoke detector. In addition, all habitable rooms must have at least 70 square feet of floor space.

Another code that should be considered when converting a garage into a living space is the electrical code. A licensed electrician must do all electrical work in a structure and must meet all code requirements. This includes installing additional electrical outlets, smoke detectors, and carbon monoxide detectors.

It is essential to also consider the plumbing when converting a garage into a living space. If you are adding any new fixtures or appliances, it is necessary to have a plumbing permit and to have all work done by a licensed plumber. All new plumbing must also meet all code requirements.

Attached Bedroom:

If you choose to just convert the garage into an attached bedroom, there are fewer building codes that you must adhere to. However, it is still essential to be aware of some of the most essential principles, such as habitable rooms. A bedroom must have at least 70 square feet of floor space, a window, and a door that opens and closes independently.

In addition, it is essential to make sure that the bedroom is adequately insulated. The California Energy Commission has minimum insulation requirements for bedrooms.

Top 6 factors that are included in New Garage Conversion Permit:

Here are the top six factors included in a new garage conversion permit. Let’s look at them one by one,

1. Floor area and height:

The total floor area should not exceed 30% of the ground floor area, and the height should not exceed 10′ from the grade plane.

2. Roof slope and overhang:

Minimum 3/12 roof slope is required, with a 12″ overhang on all sides.

3. window area and location:

At least one window must be provided that meets egress requirements, and it must be located within 5 feet of the door.

4. Wall height and stud size:

The minimum wall height is 7′; the minimum stud size is 2×4″.

5. Interior finishes:

All interior finishes must meet fire-resistance ratings and smoke-control criteria.

6. Mechanical and electrical systems:

A licensed contractor must do all mechanical and electrical work and must meet all applicable codes.

Documents Required for Garage conversion Application:

Here are the documents required to apply for a permit,

  1. Permit application form
  2. Title 24 energy requirements worksheet, supplied by the city
  3. Site plan showing existing and proposed development
  4. Floor plans for all levels of the living space. The existing foundation plan is preferred
  5. Building code reference guide (if you are not already familiar with building codes)
  6. Garage conversion permit fee:

The cost varies depending on your area, but here in San Ramon, it is $735 plus any additional fees that may apply.

Steps involved in Garage Conversion:

Here are some steps to make sure that you are on track,

  • flooring
  • parking
  • space conditioning
  • Mechanical systems
  • Life safety

let’s look at them one by one

1. flooring:

To have a garage converted into living space, you must have at least one habitable room with a minimum of 70 square feet. In addition, your new rooms need to be on the same level as the existing garage or higher.

2. parking:

Before you begin construction, be sure that there is enough parking for the number of vehicles required by code. For example, if you have two cars and eight people who live in your home, you will need 16 spots total (two per car plus eight). When counting parking spaces, a space can include a location in an open driveway or covered parking area.

3. Space conditioning:

To make any habitable, it needs insulation, weatherization, and ventilation. So let’s start with insulation.

Make sure the new conversion has insulation. California Energy Code requires at least R-19 insulation in exterior walls and R-38 insulation in unfinished or finished ceilings. In addition, certain rooms will need additional insulation based on their usage.

To ensure that your room is weatherized, be sure that all windows and doors meet egress requirements of a minimum of 3 square feet for every occupant and a maximum of 5 zones where doors open directly into a bedroom.

Code requires ventilation for habitable rooms, laundry rooms, bathrooms without showers, kitchens without ovens or cooking appliances, any space with electric heaters over 9kW, and any ducted HVAC system as central heating and air conditioning.

4. Mechanical systems:

All service openings must be weather-stripped and caulked to minimize air leakage into the garage. This is very important for fire safety reasons because there need to be no more than 3,600 square feet of unventilated space in the dwelling.

5. Life safety:

All garages must be adapted to meet life-safety requirements per California Building Code Title 24. This means that if your garage is more than 200 square feet, you will need to install a second egress window of at least 3 square feet located within five feet of the door. There are also other requirements, such as a smoke detector in each bedroom and on each level of the living space.


There you have it, folks, everything you need to know about converting your garage into living space. Make sure you check with your local municipality to see what specific code requirements apply in your area. And as always, consult a licensed contractor if you have any questions or concerns.

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