Accessory Dwelling Units
Accessory Dwelling Units (ADUs) are an innovative, affordable, and efficient way to expand living space while enhancing property value. Whether you’re considering adding an ADU to house family members, generate rental income, or create a private workspace, understanding the process and benefits is essential. Here we answer the most frequently asked questions about ADUs. Robert Hauser Construction is here to help you make informed decisions every step of the way.
1 | What is an ADU and how much does it cost?
An accessory dwelling unit (ADU) is an independent residential dwelling unit located on the same lot as a stand-alone (i.e. detached) single-family home. ADUs are known by many different names throughout the Bay Area, including accessory apartments, secondary suites, and granny flats.
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Construction costs will depend on the design of the home and the quality of the building materials. The average you can expect is between $100 and $200 per square foot. As an example, for a 500-sq-ft garage level ADU with a small kitchen and bath, costs will be roughly $50,000 to $100,000.
3 | Will building an ADU increase my property taxes?
Construction of a new ADU will not trigger a reassessment of the entire property. As with other types of new construction, only the value of the new construction will be added to the property's assessed value.
4 | Will I need a building permit?
Yes you will need a building permit. The objective is to build a legally sanctioned individual housing unit. This means it complies with relevant building safety codes, including plumbing and electrical. Also, it will have a designated address and will have individual mail delivery. This objective will require a building permit to accomplish.
5 | Does the ADU have a separate address?
Yes, an address will be assigned to the ADU as part of the building permit process. Individual mail delivery will be a part of this process.
6 | Will I need to hire an architect?
Hiring an architect is not required. Depending on the scope of the ADU project planned, you may not need an architect. If the project involves turning a finished or partially finished basement area into an ADU, very little design work will be required. If a floor plan is required for permitting, RHC will draw the plans.
2 | What is the difference between a Two-Family Home and an ADU?
The difference between an ADU and a multi-family home is that the ADU is typically owner occupied. In a true multi-family unit, the owner may not live there, nor are they required to be a resident. If you are occupying the main dwelling, you are allowed to rent out the ADU to an unrelated party. Specific conditions are subject to local regulations and should be confirmed before moving forward.