Accessory Dwelling Units are common residential additions that can increase property value and provide extra living space. They are common throughout California because of the high number of growing multigenerational households. When the existing structure no longer has enough space, families simply build an ADU to make more room.
Here at GreatBuildz, a free service that connects homeowners in Los Angeles, Orange County, Ventura & San Diego with reliable general contractors, we get inquiries from homeowners every day about their ADU placement and project tips – here are some key points you need to know.
How do you decide the best location to build an ADU on your property? What factors might influence this decision?
Types of ADUs
Before deciding on the ADU placement, you must choose which type of ADU your family needs. These are the main types of ADUs and their standard arrangements:
- Detached ADU: An isolated unit often placed in the homeowner’s available yard space. The backyard is the most popular ADU placement because of its seclusion and privacy.
- Attached ADU: A connected unit that extends from the primary residence. It can be a new build project or a garage conversion.
- Above Garage ADU: A unit attached above an existing garage.
- Garage Conversion ADU: An existing garage becomes a new living space. It can be attached or detached.
- Interior Upper-Level ADU: A unit in the attic attached to the primary residence by an outdoor stair and private door.
- Junior ADU: A separate space created within the existing single-family home. It must have a separate exterior entrance and is not required to have its own bathroom.
As you can see, each variety already sets some ADU placement parameters. The attached ADUs have predetermined locations in the garage or attic. Detached ADUs have more flexible placement options, making them more popular for residential purposes. In fact, detached ADUs are so popular that they have taken on another name — “tiny homes.”
What to Look for When Deciding Your ADU Placement
You need to do a thorough property and community evaluation to determine the best ADU placement. If you notice any of these features, you could have an ideal ADU location.
1. Detached Garage
Detached garages are the holy grails of ADUs. If you already have a separate garage, you can easily convert it into a new living space. A renovation project is almost always cheaper than building an ADU from scratch. However, the conversion must meet some requirements — including a kitchen, bathroom, living space, and a separate entrance — to become a legal ADU in California.
For a full ADU, cities will typically require you to put a wall up behind the garage door (and homeowners will typically remove the garage door itself). However, if someone wants to turn their garage into more of a flex space without going the ADU route, they are certainly welcome to maintain the aesthetic and function of their garage door.
The garage door technically counts as a separate entrance, but it needs to have both manual and electrical controls. Having both ensures that the entrance stays operational during power outages and that the resident doesn’t get locked outside.
2. Flat Lot
Anywhere on your property with a flat grade is a viable spot to build your ADU. Sloped lots require much more time and labor, increasing the project’s costs. California isn’t the flattest state in the country by a long shot, but your property might be an exception. You can quickly determine the percent of slope and find your yard or driveway’s flattest spot.
3. Deep Lot
A deep lot with a secluded driveway or backyard is an excellent place for an ADU. You should give your ADU maximum privacy, especially if a relative is going to live there. You can also make your ADU feel more secluded by surrounding it with landscaping features after you’re finished building.
4. Corner Lot
Corner lots offer additional privacy, but they’re also great because they allow you to maximize your ADU’s size. Size doesn’t play a huge role in an ADU’s construction costs if you’re building a detached unit, but typically you can assume the larger structure you build, the cheaper the price will be on a per-square-foot basis. If your home is on the corner of the block, you could create the biggest ADU in the neighborhood!
5. Large Driveway
A property with a sizable driveway is a practical property to build an attached or detached ADU. The driveway can serve as parking space for the new ADU, which is a state requirement in some cases. If you bought a property just to build an ADU and live more than .5 miles away from public transit, you must provide one parking space per unit, according to California housing laws. A large driveway is great because it reduces the need for the ADU tenants to rely on street parking – which many know can be VERY difficult here in LA.
6. Street Access
Street access is extremely valuable if you plan on building and renting out your ADU. It will streamline the construction process because it’ll be easy for contractors to get heavy machinery and materials on to your property.
It also gives the tenants more independence and privacy because they don’t have to walk through your property to get to the ADU. They can also come and go as they please without creating a disturbance. These benefits are even greater if the street is a quiet alleyway.
7. Public Transportation Access
The same logic applies to public transportation access. The most convenient ADUs for renters are nearby bus stops and subway stations. People without vehicles can rent your ADU, significantly expanding your tenant options. Public transportation access is also convenient for big families with only one or two cars. Not to mention, if you’re within a 1/2 mile from any transit stop, your city may not require you to provide additional parking for the unit.
Property Conditions that Might Limit Your ADU Placement
You also need to consider your property’s weak points. Although ADUs are versatile structures that come in an unlimited number of shapes and sizes, these property conditions might limit their design.
Communities in SoCal are notorious for their sloping property lots. Building an ADU will be difficult if your property has a steep slope. You can still move forward with the project, but expect the costs to increase significantly. Building on a hill requires more site maintenance, erosion control, and a unique foundation.
Your property’s landscaping can also get in the way of your ADU. California tries to avoid deforestation as much as possible for residential construction. If your property has any large trees, you will likely need to create a tree protection plan. Aside from the local legislation, removing bushes, trees, and root systems is a big hassle during construction.
3. Surrounding Structures
If you want to build an ADU from scratch, you might have to tear down some surrounding structures, including old storage units, garages, and sheds — which could be a dealbreaker. You also have to watch out for overhead power lines and electrical poles. They might limit the size or shape of your ADU.
Find Your Ideal ADU Placement
Your ADU will be right at home in the state of California. This state is full of people willing to pay for a safe, secluded living space. You just have to find the proper placement. Keep these positive and negative qualities in mind as you evaluate your property and you will find an ideal ADU placement in no time!
When it comes to finding the best ADU and garage conversion contractor in Los Angeles, Orange County, Ventura, or San Diego – GreatBuildz is simplifying the contractor search. GreatBuildz is a free service that connects homeowners with reliable, thoroughly screened general contractors and provides project support from start to finish.
Call now (818.317.3567) to chat with a real person about your next renovation project or visit our website for more information: www.greatbuildz.com
Rose Morrison is a home & construction writer from Pittsburgh, PA. She’s the managing editor of Renovated, a web magazine for the real estate industry.
She’s most interested in sharing home projects and inspiration for the most novice of DIY-ers, values she developed growing up in a family of contractors.