From Backyard Cottages to Full Homes: The Rise of Detached ADUs
In our previous article, we talked about what is an ADU. We have two types of ADUs: attached and detached. ADUs are becoming a key part of the future housing market in all over the world. They offer an affordable alternative to increasing housing costs, and one of their biggest advantages is being eco-friendly. A detached ADU is often considered a better choice than an attached one, because it can generate additional income, provide more living space, and support sustainable living at a lower cost.
If you want to know about the benefits of a detached ADU compared to an attached ADU, this article will highlight everything you need to know about detached ADUs before making a choice.
Detached ADUs Meaning
A detached ADU is a standalone unit built on the same property as the main home. It has its own foundation, walls, and utilities, separate from the primary residence. Since they are not connected to the main residence, detached ADUs can be designed more freely, allowing for a variety of architectural styles and layouts. These units can be used for rental purposes, guest houses, home offices, or even Studio apartment.
Quoted from Site moval.gov about Detached ADUs:
They are self-sufficient dwellings and contain a kitchen, a living area, bathroom facilities, and bedroom(s) with a maximum size of 1,000 square feet. There should also be privacy from the main dwelling.
Advantages of Detached ADU
1.Privacy
A detached ADU is standalone structure which means it offers a high level of privacy for both occupants of the main home and the ADU. The distance between the ADU and the main house ensures more privacy for both occupants, making it ideal for long-term rentals. The separation also means less noise transfer and more personal space for both the main house and the ADU.
2.Property value
Detached units can add significant value to a property, because they are viewed as independent living spaces with all the amenities of a small home. Detached ADUs are considered a premium asset when it comes to resale value.
3.Predictability
Detached ADUs generally have more predictable construction costs compared to attached ADUs.
Because they are completely separate from the main house, there is less chance of unexpected problems that often happen when connecting to an existing structure.
Additionally, building a new unit makes the area of work clearer from the start and reduces costly surprises
4.Design freedom
Homeowners have more creative freedom when building a detached ADU since it doesn’t have to conform to the design or structure of the existing home.
Disadvantages of Detached ADU
1.Higher construction costs
Detached ADUs costs more due to the need for separate utility connections, building foundations, and potentially more extensive construction work.
According to a report by Terner Center for Housing Innovation, the average cost to build a detached ADU in Los Angeles, California ranges between $150,000 to $400,000 depending on its size, materials, and location.
For more information about the cost and size, check out our article “ADU in Los Angeles” on our website.
2.Zoning restrictions
Detached ADUs may face stricter zoning laws and building codes depending on the area. Some areas have lower height limits, while others do not. If it faces stricter zoning, the permitting process becomes more complex and time-consuming.
3.Land use
These units require more yard space which may not be ideal for homeowners who wish to preserve their outdoor areas for other uses or have smaller lots.
Detached ADU Plans
ADU floor plans range from 400 to 1,500 square feet. Some ADU plans feature garages or two-story layouts. The benefits of using pre-approved or standard ADU plans make sense for homeowners looking to reduce costs. It’s also often faster to use existing floor plans vs start completely from scratch with a custom ADU plan.
These designs comply with the Ontario Building Code, but they do not guarantee compliance with the City’s zoning rules for site layout. Each property must be checked, as setbacks and site conditions may differ.
Site Location for Detached ADUs
You might be wondering where detached ADUs should be located. A detached ADU can be added anywhere on the property, in the front or the back of the primary house. Make sure to pick a spot that doesn’t obstruct the view of your primary house.
Examples of Detached ADUs
- Personal Gym: Enables private access to workout equipment and a fitness area at home for those who want to work out anytime during the day without restrictions and avoid extra gym costs.
- Studio Apartment: A compact secondary unit with an open-planned room that is designed to combine the living room, bedroom, and kitchen into one. In terms of size, it usually ranges from 270 to 485 sq ft. It is ideal for singles, couples, or college students.
- Home Office: Provides a quiet, professional environment for remote work or art studio, separate from the main living areas.
- Multigenerational Housing: A private suite for extended family, like elderly parents or young adults, which gives them affordable living space as they gain independence while keeping them close.
- Kids’ Playroom: For parents who have more than 2 kids, they can use detached ADUs as a dedicated area for children’s toys and activities, keeping the main house neat.
- Guest Rental: Provides a private space for short-term visitors or long-term tenants, generating additional income.
What Is Backyard Cottage?
Detached ADUs are also called Backyard Cottages or Backyard Homes, because they are usually built in the backyard of the main house. Backyard cottages are their own residential structures, and they have complete tiny house units containing a kitchen, bedroom, and bathroom to function as a separate home. Backyard cottages, while offering the look and feel of a standalone home, are not legally separate properties. They are permanent parts of the main property and cannot be sold separately. The construction of a backyard cottage must comply with local zoning regulations and building codes, and typically require permits and inspections.
How Much Does a Backyard Cottage Cost?
The national average cost for building a backyard cottage is $100 to $500 per square foot. This typically depends on factors such as your location and the size, design complexity, and materials for your backyard cottage. The most costly option is due to the fact that the structures must be built from scratch and require all utility connections to be installed independently.
Conclusion
Detached ADUs, also known as Backyard Cottages, offer a flexible way to expand living space, generate extra income, and maintain privacy. These standalone units, with full amenities, can serve as guest homes, home offices, studios, or multigenerational living spaces, while also increasing property value. Despite higher construction costs and potential zoning restrictions, their benefits including design freedom, independent functionality, and sustainable living make detached ADUs an attractive option for homeowners.
Why Us?
We’ve created several designs for detached ADUs. Let’s take a look at a few of them so you can get a better choice.
RANDOLPH
This Randolph project is a garage conversion into a modern detached ADU with an approximate size of 517 sq ft. The layout includes a spacious living room, an open kitchen with dining space, one bedroom, and a full bathroom. Designed for both comfort and efficiency, the ADU follows California Building Code standards with dual-pane windows, fire-rated drywall, and energy-efficient insulation. The open floor plan maximizes natural light, while the high-quality finishes ensure permanence and low maintenance.
MARBISA
The 458 sq ft ADU includes a second-bedroom option, with a large open space living, and kitchen. It also includes a full bath. The unit is built to California Building Code standards, featuring energy-efficient insulation (R-15 walls, R-30 ceiling), dual-pane windows, and low-flow plumbing fixtures. It provides full ventilation per CBC requirements, fire-rated drywall between the unit and garage, and on-demand water heating. Exterior finishes include durable stucco with weatherproof detailing, and all interior finishes were selected for both quality and sustainability.