Since your ADU will likely be rented at some point, it should be built to code. Building codes ensure safety but are complex, so you’ll want to consult an architect to design your new unit. They will have all the tools at their disposal to design a living space that meets state and local requirements and that can make the most out of small spaces. Alternatively, there are firms building ready-made ADUs that have already created code-compliant designs. Make sure they say they are compliant in your state.

But, you can begin for free by just taking a look at floor plans and pictures. The ADU must include four elements: a place for sleeping, eating, cooking, and sanitation, but you can make each smaller or larger. Think about what spaces are important to you. Do you want an office nook? Is just a shower fine? Do you want the space all ADA accessible? One or two-bedrooms?

Here are links (1, 2, 3, 4) that show interesting designs where you can see general floor plans and pictures.

Bear in mind that the final design of your ADU may be subject to change as you go through the permitting and finance processes. You may also wish to consider purchasing ready-made ADU building plans or even a prefabricated, standalone ADU that can be installed on-site.

Wheelpad and Backyard ADUs  are New England companies with many prefabricated homes and designs for you to peruse. Preferred Building Systems is another local supplier. New Frameworks offers small units that focus on carbon storage. If you are thinking of using pre-built or modular designs, think about how a crane will get to the site. Most firms will do a low-cost site visit to evaluate the site.

Your final design will help you determine how much money you need to execute the project.

Here are some handy guides for design if you want to read further.

Continue to the FINANCING page.