ADU Garage Conversion


Is it legal for me to convert my garage into an ADU

You can construct a Garage Conversion Unit if you have a single-family house in California that is within residential zoning. You will need to convert your garage into a rental in each city or county. However, California laws have made it possible for every homeowner to convert their detached or attached garage into a livable rental unit.

What is a Garage Conversion ADU (ADU)?

Los Angeles City Ordinance No. 186481 outlines what an ADU is, and where one can be built. According to the City of Los Angeles, an ADU is defined as follows:

Do I need to convert my garage?

There are many factors that will influence whether or not your garage should be converted into an ADU. Every homeowner will have their own reasons for thinking about a garage conversion. To decide if a garage conversion is right for your needs, it is important to carefully weigh the pros and cons of building a rental unit, guest house, or home office.

Garage Conversion vs. Detached/Attached ADU

Many homeowners weigh the pros and cons of converting their garage to build an ADU elsewhere on their property. Converting a garage is more advantageous than building an ADU.

  • Advantage #1 – Price
  • A garage conversion ADU costs significantly less than a detached or attached ADU. Conversions save money on foundation, framing and roofing costs because the garage is already in place.
  • Advantage #2 – Savings
  • Garage conversions are usually easier to permit and take less time than building a new unit.
  • Many garage conversion ADUs are possible to design, permit, and build in as little as six months. This is a great way to increase the living space on your property.

There are disadvantages, however. These are the two biggest disadvantages.

  • Disadvantage #1 Loss Covered Parking
  • Converting your garage does not mean that you have to replace any parking. However, garage conversions will result in less parking and less storage. Potential buyers could find this a problem.
  • Disadvantage #2 Lower Return On Investment (ROI).
  • Converting your garage into an ADU will increase the property’s value. This is because it adds habitable square footage. The ADU will increase property value because single-family homes are valued based on their characteristics and useable square footage.
  • The flip side is that your garage is being converted, which can be a valuable California amenity. Losing a two-car garage standard will decrease the value of your home, offset by some of the property increase that you get with the addition of an ADU.

It is important to assess whether the garage’s loss is significant and how it may affect your property’s future value.

What is the cost of converting my garage into an ADU

Garage conversions typically cost between $80,000 to $175,000+. Price will depend on the size and quality of the finished materials.

We can take as an example three garage conversion projects, and their approximate costs.

  • Garage Conversion #1 Simple and Modest
  • Budget Estimate $80,000+
  • This garage conversion is the fastest and most cost-effective. This allows for no extra square footage or changes to the garage’s overall structure.
  • This scenario would see you add an efficiency kitchen, a small 3/4 bathroom, and a mini-split HVAC system to heat and cool the space. Finally, bring the electrical wiring up to code to make it livable. Also, the building materials used would be simple and modest (i.e. no fancy countertops or kitchen cabinets).
  • This project will result in a clean, safe ADU that is livable and comfortable.
  • Garage Conversion Example #2 Big Structural Updates
  • Budget Estimated $120,000+
  • A straight garage conversion may not be what you need. Perhaps your garage needs structural improvements. Perhaps you are looking to add a small addition or vaulted ceilings to your ADU to make it feel bigger.
  • The ADU would be equipped with a larger kitchen and full bathroom. ADUs will be charged separately for electricity and gas. Your contractor will also alter the roof structure in order to create a vaulted ceiling.
  • This budget project will feel more like a small home and will have larger interiors. The conversion is more private with a separate bedroom.
  • Garage Conversion Example #3 Full Custom Build
  • Budget Estimated $175,000+
  • The fully customized rebuild is the next level of ADU garage conversion. The rebuild will involve the demolition of the garage and will also include a larger floorplan or an addition of 2 stories.
  • This scenario allows the owner to choose a floorplan that best suits their needs. It will not be possible to prove that the ADU was originally built as a garage. The ADU can be furnished with luxury finishes that will suit any taste. It can also include multiple living and sleeping areas.
  • ADU projects like these will significantly increase the value of your property and will be more expensive to build. They are a great option for homeowners who want to make a home office or guest room on their property.

What is the time it takes to convert my garage

The scope of work undertaken by the owner will also affect the garage conversion timeline. A simple, straightforward conversion can take six weeks to plan and permit, while ADU construction in los angeles may take 6-8 weeks.

Three months is a better time frame for larger ADU projects. Another 4-6 months are reserved for construction.

The overall project timeline, which includes design, permitting and construction, should take around nine months.

Is Garage Conversion ADU worth the investment?

A garage conversion is a great way for property owners to increase their return on investment (ROI). In almost all cases, the property’s value will rise more than the cost of the garage conversion. The benefits go beyond financial. You will be more productive in your private office. You will feel a sense of relief knowing that your elderly loved ones have a safe, comfortable place to call home. You can also have fun hosting out-of-town visitors in your private guest room.

Garage Conversion ADU Floorplans

Here are some examples of how a garage conversion ADU might look. You can choose to build a small garage conversion or a larger one. A good design and a plan are the best places to start.

Modest Garage Conversion Plan

  • Below is a plan that shows how to convert an attached 2-car garage into a garage. This ADU type is the cheapest to plan and build. This ADU floorplan features a studio apartment conversion with small kitchen, full-size bath, and large living/bedroom area.
  • A family of two young children designed and built this ADU. They wanted an apartment for grandma or grandpa to stay while they were visiting long periods.

Garage Conversion Plan With Small Addition

  • Below is a floorplan that shows 100 sq. FT. addition to an existing 2-car detached Garage. This ADU was designed for a young couple who wanted to turn their garage into a rental unit to offset their mortgage payments and help them move into their dream house a few years sooner than they had planned.
  • A small addition was made to the property to allow for a one-bedroom ADU. This is in place of a smaller studio ADU which would have been possible without it. With a slight increase to the overall design cost and construction cost, the one-bedroom ADU raised the rent they were able to charge.

Garage Conversion Rebuild With Second Story Addition

  • Sometimes, your garage isn’t big enough to house the ADU you require. A garage conversion rebuild is an option in this case. It allows you to increase the floor space and footprint of your garage by up to two-thirds.
  • This plan was created for a couple who were both hardworking and wanted to work from home. The ADU was needed to be used as an office, guest suite, or pool house.
  • The solution we designed had an open floorplan, with the first floor being a living room. The second floor was a home office and doubles as a guest suite for visiting relatives.

Los Angeles: How to Legalize Illegal Garage Conversions

Los Angeles has a program that will legalize your ADU if you have previously converted your garage to an ADU or bought a home with an ADU not permitted.

The Unpermitted Unit (UDU), Ordinance (Ord. No. 184,907). You must follow a 6-step process to be eligible. Below are the instructions for the City of Los Angeles.


Garage Conversion ADUs are a great way of adding livable space to an already existing property at a very affordable price. Garage Conversion ADUs are a great option if you have immediate needs for additional living space or housing, or if you’re looking to rent an apartment or house.

Converting your garage will mean removing off-street parking which is an important commodity in Los Angeles. You should consider all options when converting your garage. These include detached and attached ADUs that might be worth considering.

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