Mother-in-Law Apartment Floorplans & Designs

Chapter 08: Mother-In-Law Apartment Floorplans & Designs

An architect will come to your house for an initial consultation and will require an up-front retainer if you decide to move forward with them. The architect will typically offer you three to four different floor plans to come up with something you like, taking into account what is most important to you. Make sure to use your two or three variations wisely as you will have to pay extra to keep making changes to your design thereafter.

When you have a finalized floor plan, it is time to draw up your building plans. Your architect will usually recommend a structural engineer who can get your plans stamped and in Title 24 compliance. (Note: Konhoff Company’s architects take care of the submission process with the city.)

Pro tip: Make sure your architect, contractor and structural engineer communicate with each other to make sure you design your project within your budget and to avoid costly mistakes.

Most cities we have seen have height restrictions that only allow you to build a 1-story ADU. There are all kinds of interesting and cool pictures online with floor plans that include lofts. Some even dig a few feet into the ground so they can fit in a cool loft without going over the height restriction. Unless you have a very large budget or don't care about your project as an investment, these type of floor plans are not advised. Right now, the construction costs are expensive in high-demand California coastal areas and you will end up increasing your budget. If you want to keep your project under $200K, stick with the basics. You may see really cool floor plans from ADU friendly cities like Portland, Oregon. But keep in mind, construction costs in Portland are very different from the Bay Area.

Vaulted Ceilings
Higher ceilings are very nice and make the ADU feel bigger but add considerable cost. One way to get the nice open feeling without the high cost is to utlize scissor trusses, which are no more expensive than regular trusses.

Flat Roofs
Flat roofs are popular and give a nice contemporary modern look. They are more expensive and you may have problems down the road. They tend to have more leaking problems than a pitched roof. Again, if you are on a fixed budget of less than $200K, these types of decisions can put you over the top. So make sure you know how much you are adding to the project cost with these types of design decisions.

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The 2019 Guide to Building an ADU in California
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For homeowners who want to make the smartest investment when building a backyard cottage, granny flat, accessory dwelling unit, or garage apartment.