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All about ADU's

ADU's are Accessory Dwelling Units. ADU's are separate, independent residential living units located on the same lot as a primary residence. The ADU cannot be sold separately but can be rented out by the homeowner or as local laws allow. This building type is becoming more popular as local laws change to allow them in response to the need for more affordable housing.

1 - Types

ADU's can be attached to the main house or detached. An attached ADU might look like a mother-in-law suite in a separate wing of a home or a finished basement with an outside entrance. A detached ADU is one that is separated from the main house. Common setups for detached ADU's are cottage houses or units over garages. What makes it an ADU is having for cooking, sleeping, and bathing and a separate entrance. ADU's are excellent options for many groups of people including eldery, adult children living at home, young professionals, and single parents. All of these groups desire the comfort and autonomy of their own space but with less upkeep, responsibilities, and cost than is associated with a primary home. Since ADUs share the infrastructure of an already developed neighborhood, they are more sustainable than other types of housing.

2 - Process

If you are interested in building an ADU on your property, the first thing to do is check your local zoning to see if they are allowed. You can do this by contacting the Planning Department at your local government offices. If ADUs are allowed, you will then want to find an architect to help you plan and design your ADU. Even if you find a stock ADU plan, it will need to have a site plan, foundation, and editing to conform to local rules and what might start out looking like a bargain becomes a nightmare as you pay to make changes to a plan that was developed without you or your site in mind. Since ADUs go in backyards, they are usually designed per each site so they can but up against setbacks and be designed with site utilities, open space, access, and privacy in mind. Your architect will take you through the steps such as getting a site survey, finding a contractor, and obtaining the necessary permits.

3 - Layouts

Your ADU will be limited in size either outright or by the size of land you have available. ADUs are generally between 615 and 1,000 sf which is space that must be used wisely to get all the amenities of a home included inside. 615 square feet is large enough for 1 BD/1BA units and 1,000 sf works for 2 BD/2BA. If you have an upper-level ADU like one over a garage, you can either have the stair inside or outside the unit. It is really important to consider how the ADU is accessed and how the yard space is shared (or not) with the main house. Don't forget parking! Many zoning codes will require you to have a parking space on-site for your ADU tenant.

4 - Cost

You're essentially building a small house with everything that goes along with it except the land and site utilities. So naturally costs can vary, but how much are we talking about? In my experience, cost can be as low as $60k to convert an existing small space to an ADU to $300k or more for a larger unit with some luxury options included. Sometimes people tell me that they ask contractors what an ADU will cost and they get wildly differing answers. This is because until the contractor has plans in hand that explain what you want, they can't accurately price anything. 

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