Building An A.D.U in California?
Accessory Dwelling Units (ADUs) in California
ADU DESIGN
For California residents, specifically property owners interested in earning supplemental income and increasing the value of their property, it is critical to understand the new legislation passed on ADU’s (Accessory Dwelling Units). If you own a residential property in California, the new legislation may allow you to build an ADU, also commonly called a granny flat, in-law suite, casita or backyard cottage on your property. In addition to producing supplemental income and increased property value for the single property owner, ADUs could also help solve some of the large scale environmental and economic issues that California faces for the future.
As the population rises in California in parallel with the demand for housing, we must find new and affordable places for our residents to live. The shortage of housing has caused a dramatic increase in housing prices far exceeding the rest of the country. Californians are having difficulty finding homes in areas with high economic and career opportunity. The California Legislature recognized these issues and has responded with the introduction of laws which allow the building of ADUs to existing residential lots.
We hope the following information will help inform Californians on the benefits of ADUs and make them commonplace in our State.
What is an ADU?
In general terms an ADU is a self-contained unit which contains all the necessities one needs to live such as a bedroom, kitchen, and bathroom. ADU units can range in square footage up to 1,200 SQFT or 50% of the area of the primary residence per the California legislation. Some jurisdictions will have lower maximum square footage requirements. ADUs are typically single-story structures and can take one of five different forms, including: detached unit, attached unit, repurposed space, inside of an existing home, garage apartment, or an above garage unit.
Financial Benefits of ADUs
The cost to build an ADU is substantially lower than alternative housing options because the land is already purchased and there typically is not a need for additional infrastructure or parking structures.
The upfront financial investment required to construct a small backyard unit is much lower compared to the massive funding and endless rounds of capital raising for a large apartment complex.
Depending on the jurisdiction, property owners are typically permitted to rent out the ADU on their property for additional income. The rental rates will vary based on demand and location, but we have seen several instances where the rental rate earned from the ADU nearly covers the cost of the mortgage payment for the primary residence. This of course will vary on location and mortgage terms.
Environmental Benefits of ADUs
In addition to the lower cost of building ADU units, the environmental impact of their construction is typically much lower than that of a ground up apartment complex, townhouse block, condominium structure or a similar large-scale housing structure. A large ground up residential building usually requires the devastation of natural habitats. Significant amounts of earth work, grading, and installation of impervious surfaces disrupt natural drainage patterns and destroy large ecosystems of California flora and fauna.
By inserting ADUs onto existing developed land (typically backyard lawns), we help to preserve larger swaths of natural undeveloped lands. The goal is to reduce urban sprawl by densifying the already developed areas. With the shortage of land in Southern California, specifically along the coastal regions where many young people want to live, it is critical that we preserve as much of the undeveloped land as possible while still finding a way to address housing demand.
Rost Architects ADU Design
Cost of Building an ADU
A great study was performed by the county of Santa Cruz on the cost to build an ADU in their area. The costs will vary throughout the state, but their analysis found that the average cost to build an ADU unit was roughly $150,000. To view the study in more detail click here.
Permitting Timeline Reduction for ADU’s Compared to Large Scale Housing Typologies
With the increase of environmental, fire requirements and safety regulations required, we have seen increased timelines to get large residential buildings permitted and built. Although ADUs will also have to go through a permitting process, the timeline is often far less compared to alternative large-scale housing developments. The California Legislature ruled that the approval of ADUs should be a “ministerial” approval, which is less intensive than a typical approval.
Typical ADU Zoning and Building/Safety Requirements
Below is a broad stroke overview of some of the most common ADU zoning and building requirements. For the most up to date California legislation governing ADU’s, click here.
Many Jurisdictions have a minimum lot area requirement for properties to which an ADU can be added. For example, Newport Beach currently requires 5,000 SQFT as the minimum lot area to add an ADU. If your lot is smaller than 5,000 SQFT and within the City of Newport Beach you are not permitted to build an ADU on the lot.
Defining the setbacks from the property line, height limitations and setbacks from the primary residence are key to an ADU project. These will vary based on the specific jurisdiction. In most jurisdictions an ADU will need to be at least 10 feet from the primary residence. Detached units will usually be confined to one story in height. For example, in Newport Beach the maximum height limit is one story of 14 ft.
In general, the intent of the legislation is to maximize the potential for ADU development. The local county or city can establish their own regulations, however, these should not make it unnecessarily difficult build an ADU. It is important that you fully understand the local codes which your ADU project must comply with or work with an Architect who can guide you through the process.
For the team at Rost Architects, we feel that it is essential for ADUs to become commonplace in California. In order to do this property owners, architects, builders and real estate professionals need to embrace the legislation and begin to develop creative ways to inject these units into the culture and housing market. We feel that ADUs can become architectural features for properties in addition to helping solve the economic and environmental issues that California is facing.
Looking to take the next step? To get your ADU project started, email Mitchell@rostarchitects.com or view our ADU plan packages at https://www.rostarchitects.com/adu-plans. We offer a range of style and sizes in our ADU plans. Pick the one that is right for your lot or we can customize a plan to fit your needs.
