Rightsizing Your ADU Project: Your Site’s Opportunities and Constraints (pt 2 of 4)

Creating an ADU is an important decision for any homeowner. ADUs have incredible utility for families and allow for unprecedented intergenerational wealth building.  They are essentially small homes which are typically, but not always, built in backyards of urban homeowners in single family neighborhoods. As small homes, ADUs are a significant investment for the typical homeowner and must be designed to work within an owner’s ability to pay or finance the project. ADUs are also subject to the legal constraints as well as physical site conditions that inform the design. To get an ADU project to provide a maximum value to a family it must be the right size. Not too large or costly and not too small which would reduce its utility and value. To get to “a right size” is one of the most important goals of the design phase for an ADU project.

Before starting the design process, doing a deep dive into the unique aspects of your site and what size it  can support as well as the subsequent ADU size and program requirements, will ensure that you have an understanding of what is possible as well as allow for the next step which is budgeting.

Understanding the physical constraints and opportunities of your site is an important step in your ADU planning process.

This includes understanding of access points to the ADU. Which side of the home will ADU occupants use to access the rear yard if the lot is not a corner lot? What privacy issues need to be understood and addressed from both neighbors and your primary residence?. What is the best place to provide some outdoor space for ADU occupants? Map these constraints out on a simple site plan.

From there, understanding program requirements and typical sizes of various ADU configurations can help to inform your project planning.

The program requirements are your ADU needs and desires. How many bedrooms and bathrooms are needed? In general, a studio ADU can be as small as 300sf. A one-bedroom should be around 550 to 650sf. A two-bedroom, one-bath around 800sf. A two-bedroom, two-bath can be around 900sf and a three- bedroom, two-bath will need to be the maximum allowable which is 1,000sf. These guidelines can help you with preliminary planning.

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