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Want to build an ADU / In-Law Unit?

Updated: Aug 30, 2022

"I want to build an ADU / In-Law Unit on my property, where do I start?"

Well, there are really only 3 options to get started.

The first option is to search online for a set of prepackaged plans that meets all of your needs. When searching for the perfect house plan for you, there are a ton of different things to consider to ensure that you're choosing the best option. Architectural style, size of the home, how many levels to the home, number of bedrooms, number of bathrooms, and the list goes on and on. If you can dial in all of these details in with your family, and find a predesigned plan that meets all of your specific desires, this will by far be the quickest and most affordable way of kicking things off. Even if you find a plan that requires a few minor modifications, this too can save you thousands of dollars and many months of valuable time that would otherwise be spent with an Architect or Building Designer creating an entirely custom plan.

Once you've found the perfect plan, or one that requires minor modification, you will need to contact the designer and/or purchase the plans from their website. After purchasing the plans, the next step will be to check with your local building department to determine what additional documents (supporting documents) will be required to accompany the plans in the permitting process. In California, this typically includes the following items;

- Plot Plan (Typically depicting property lines, building setbacks, easements, existing structures, locations of utilities, waterways, and of course, the location of where you plan to place your ADU / In-Law Unit)

- Title 24 & Manual JDS Reports (Certified energy evaluation of the ADU which will determine the minimum level of insulation required, window heat resistance values, HVAC efficiency requirements, etc.)

- Structural Engineering (Depending on the location of your property, and the design of your online plan, you may be required to have your plans reviewed and stamped by a structural engineer)

It's important to note that your local building department may require changes to the plans and/or additional supporting documents before they will issue a permit. In many cases, property owners may decide to hire a local Architect or Building Designer to assist with this portion of the process known as Permit Application.

To search our catalog of prepackaged plans, please fee free to click here If you still can't find exactly what you're looking for after looking through our prepackaged

drawings, you're always welcome to reach out to us and discuss the custom option for your


Click here for more of our ADU / In-Law Unit plan collection

The second option is to meet with a local architect or building designer to design an entirely custom plan for your ADU / In-Law Unit. This is a great option for those who are looking to attach an ADU to their existing home, or those who just can't find the perfect online plan. Though you can expect this custom design option to cost more money, and take more time, it will ultimately result in a much more tailored experience. In addition, going this route is typically less stressful on the property owner as many design teams can provide everything needed for permit application, and an experienced Architect or Building Designer will know exactly what questions to ask to ensure that your custom ADU / In-Law Unit exceeds your expectations. You can really think of your Architect or Building Designer as your one stop shop for the entire process. If you decide that the custom route is the best option for your project, it's vital that you first talk with each designer you are interested in working with to confirm that they do in fact intend to provide this "one stop shop" experience before signing a contract.

If you'd like to reach out to discuss the design of your custom ADU / In-Law Unit, please feel free to email us with more detail about your project!

The third option is to meet with a local contractor to begin conversations about your desire to build an ADU / In-Law Unit. Often times, contractors can collect all of the details of your desired ADU, and on your behalf, they will work with a local designer to put together your plans and associated permit application documents. However, it's important to note that not all contractors provide this service. Sometimes contacting a contractor first may just result in being sent back to search for an architect or building designer. Though a contractor will ultimately be the one to build your ADU, every contractor will still require a full set of plans to provide an estimate for the construction costs, instruct them on what is to be built, and of course, obtain a building permit.

We hope to hear that this article has been of value to you! Please feel free to contact our team with any questions or concerns regarding this article. Click here to redirect to our contact page, or feel free to explore related content here.

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