Garage conversion in Los Angeles

Why converting a garage is usually the cheapest way to add a unit

A ground-up ADU means pouring a slab, framing walls and building a roof before anything else happens. With a garage, all three already exist. That is the whole reason a conversion comes in below a new build, and it is why so many homeowners start here.

What it does not mean is that a conversion is a light job. A garage was built to keep a car dry, not to be lived in. It usually needs insulation, proper windows, a new floor, plumbing brought in, an upgraded electrical supply, heating and cooling, and often structural work where the garage door opening is closed up. That is where the cost sits, and it is why an honest range for a small building is still five figures and then some.

Attached or detached: the difference that changes the price

An attached garage shares a wall with the house. That makes running utilities shorter and simpler, and it is the reason the attached range tops out lower.

A detached garage is a separate building in the yard. Utilities have to travel further, the structure is more likely to need work of its own, and the permitting can be slightly more involved. Detached conversions also tend to make the better unit, because the resulting space is genuinely separate from the house, which is what most homeowners are after, whether the plan is family, a home office or an income unit.

Both ranges are below. Which one applies to you is not a judgement call; it is a fact about your property.

Garage conversion or a new ADU?

Both give you a self-contained living space on the same lot as the house, and a permitted garage conversion is one of the recognised ways to create an ADU. What differs is how each is priced, what it costs and how long it takes to build.

A garage conversion is priced as a whole project, because you are not choosing the size: the garage is the size it is. For a typical 400 square foot garage, construction runs $90K to $110K attached and $90K to $120K detached. A new ADU is priced per square foot, because you are choosing the size: $280 to $320 per sq ft for a one-story unit, attached or detached, and $285 to $320 per sq ft for a two-story detached one.

Those two kinds of figure are not directly comparable, and we deliberately do not multiply a per-square-foot rate by a unit size to show you a total. The reason a conversion usually comes in below a new build is that the slab, the walls and the roof already exist, which is the largest single saving available.

Plans and permitting are priced separately in both cases: $5K to $7K for an attached garage conversion and $5K to $10K for a detached one, against $7K to $12K for a one-story ADU and $12K to $16K for a two-story one.

Both go through permitting first. Permitting often takes approximately 2 to 3 months, depending on the city and the project. Many garage conversion projects take around 3 months to build, depending on scope and site conditions. Ground-up ADU timelines vary by project. We can give you a property-specific timeline after reviewing your site and scope.

What a new ADU offers in return is choice. A new detached unit gives you the most freedom over layout, because nothing about it is inherited from an existing structure, and a two-story unit gets more living space out of a small footprint. Which one suits your property is usually settled quite quickly once someone has stood in the yard.

• ADU construction in Los Angeles
• How much does an ADU cost in Los Angeles?

What about the parking you give up?

It is the second question we get, right after cost. California law has changed substantially in favour of ADUs on this point over recent years, and in many situations a replacement parking space is not required when a garage is converted.

"In many situations" is doing real work in that sentence. The rules depend on your jurisdiction and on your specific property, they have moved repeatedly, and this page is not the place to give you a definitive answer about your address. We check what applies to your property as part of the free property visit, before you spend anything on drawings.

How long it takes

Many garage conversion projects take around three months to build, depending on scope and site conditions. Before that, permitting often takes approximately two to three months, depending on the city and the project.

Both of those are estimates rather than promises, and the permitting one is the less predictable of the two because it is not entirely in anyone's hands. What we can control is that the drawing set is right when it goes in and that corrections come back quickly.