Brit Builds an ADU: Who Would Want an Accessory Dwelling Unit?

Two years ago my family of three adults, a polyamorous family with my wife and husband, bought a three bedroom, two bathroom house in south Minneapolis. It’s charming and has fantastic 1940s details like coved ceilings, stucco exterior, and a smallish footprint at about 1600 sq ft. I work from home full-time and we have a boarder to help pay some of the bills and because we like the company of old friends.

So, the question is, in a three bedroom house where all three bedrooms are occupied, where are we going to put the future kids? Or more like the hypothetical in two years kid. Two years is not that long, not that long at all. How the heck am I going to be able to work full time at home without parenting full time as well? It would be ideal to have an office on our property but not within our house.

Two years is just enough time to maybe create some space for an office outside of the house. (less noise means less parenting during work time and maybe a calmer brain) As well as create a possible income stream for helping pay off that office space and maybe help with the mortgage by building an ADU to replace our garage.

So, the question here is “What is an ADU and how is it useful?”

Chris Strom Adu Lifecycle

Possible lifecycle of a house with an ADU. Thanks to Christopher Strom Architects for use of the image.

An ADU is an Accessory Dwelling Unit; basically a tiny house or apartment built on existing property. It can be attached to the main building structure or detached like an old-fashioned carriage house or Fonzie pad. ADUs are typically lauded as beneficial for aging in place, building wealth, giving teenaged and 20 something children a place to live, and maybe just as adding more space for a growing family. I heard about ADUs a while ago when I was looking at housing my aging father and kinda fell in love with the idea. I want to live in the same place the rest of my life. I moved 16 times by the time I turned 16 and I never want to move again. Having an ADU on our property will allow us to downsize when we need to without really going anywhere. It also gives us the ability to help other people achieve housing stability without living in the same space with them. We could use the space to teach our kids how to live on their own before they move on. It’s a great idea! It’s a hard idea to actually implement as demonstrated by the less than 100 ADUs built over the last four years in Minneapolis since they were legalized.

In our case we’re looking at building a detached ADU to replace our garage while adding a couple of rooms on the main level for offices for me and my wife. Our current garage was put up hastily and a bit shoddily when our house was remodeled/flipped before we bought it, and has a terrible s-shaped relationship to the alley. The garage faces the back side of our neighbor’s garage with a ~13 foot concrete pad between. Mostly, we park on the street and my two spouses drive to work while I take a bus for errands or borrow a car if needed. So, it’s a great candidate for being torn down and replaced with something actually useful.


Picture of taupe garage through back window with s-shaped connection to alley.

Picture of taupe garage through back window with an s-shaped connection to alley. Soon to be replaced?!

In Minneapolis ADUs have been legalized for owner-occupied properties for about four years now. I plan to build one.  The zoning itself is a bit complicated. Building a tiny house on a property between two garages, hooked up to the main house’s sewer and electrical will be yet more complicated I’m sure. But most of all it will be an opportunity to build our life towards living our values. Building community, building space for a growing family, and building flexibility in a denser more useful space.

Through writing about this process I hope to help other people see how the current zoning plays out in practice from financing, to hiring folks to envision and build it, through the actual build process to what the space is like to use in practice. So far we’ve secured some preliminary financing, and contacted an architect. I think the more people know what to expect out of a process the more comfortable we can all be with it and then more people will be willing to take advantage of this piece of zoning to improve our land usage, fight climate change through density, and invite more neighbors to live not just next to us but with us. Please let me know what kinds of questions you have and as we go I’ll answer them if I can.

Brit Anbacht

About Brit Anbacht

Brit Anbacht is a millenial policy wonk and general nerd. They work from home full time. Brit sometimes drives but ever more frequently takes the bus for errands. They live in south Minneapolis, and can be found occasionally on twitter @britvulcan.

13 thoughts on “Brit Builds an ADU: Who Would Want an Accessory Dwelling Unit?

  1. Frank Phelan

    Without knowing exactly what the current condition of the garage is, it would be a good idea to see if it can be moved and sold to someone else. If possible, it’s cheaper for you and it keeps a dumpster or two out of the landfill.

    1. Brit AnbachtBrit Anbacht Post author

      That is an interesting idea! Unfortunately while new the garage has several spots where the nails aren’t actually connected to the studs. But at bare minimum selling the garage door would be helpful.

    2. Serafina ScheelSerafina Scheel

      I once bought a used garage from the Badger Man, who had a lot of them down off of West Seventh back in the day. It was the best.

  2. Lou Miranda

    Nice introduction to ADUs, with a great graphic.

    It sounds like you take the bus. Are you close to a major transit line or bikeway? What kind of transportation options are there for the ADU dweller(s), and is it likely the dweller would be carless? I’m wondering how transportation options affect an ADU’s desirability. Thanks.

  3. Lindsey WallaceLindsey Wallace

    Have you talked to zoning yet? Single family homes have a minimum parking requirement of one space. ADUs don’t have an additional requirement as long as the minimum for the main structure is met. If you’re removing your only off-street parking spaces, you’ll probably need a variance unless you can provide a small parking pad.

    1. Brit AnbachtBrit Anbacht Post author

      Hi! So, we’re probably going to still have at least one garage space in future. I’m a bit of a policy wonk so I’ve done a fair amount of zoning research on ADUs. (probably a future post or two?) Thanks for your insight!

      1. Lindsey WallaceLindsey Wallace

        Got it, thought you were discussing building a cottage without garage. That’s what I want to do someday. If the ADU won’t happen for a bit it’s possible parking minimums won’t exist once you move forward. I work in planning for the city so just wanted to flag that 🙂

      2. wilj

        Yea, I’m guessing the parking reqs won’t be enforced pronto following the vote on 2040…

        One of the things that you /could/ consider would be to put an ADU above a garage. Here’s a street view image of one I see a lot that’s always intrigued me (I think the link will work? Approx address 1400 Broadway St NE).,-93.2393759,3a,75y,168.51h,86.48t/data=!3m6!1e1!3m4!1snemt9hOWXJ9EZFNGslk04A!2e0!7i13312!8i6656

        The thing about garages is that, while I don’t think cars will be as ubiquitous in the future as they are now, a garage is still a really terrific space for keeping things like: bikes, shovels, wheelbarrows, etc. Additionally they are an ideal space to work on projects and use as a workshop. So regardless of the vicissitudes of car-culture I can see a desire to keep one around..

        Anyway, enough about garages..

        What I would love from your post, Brit, would be a decent breakdown of the various costs of doing a detached ADU, separating utilities, running sewer, etc. And the various hurdles you run into that you didn’t foresee, or other odds and ends that surprised you. For example, the ADU that I included the streetview for exceeds the zoning allowances for garage heights – why? — if you come across aberrations such as this with your project, I’d find these things interesting and informative.

        As a side-note, I’ve found the idea of insulating an ADU up to passivhaus standards to be a plausible goal as the extra insulation shouldn’t be that much more expensive on an initial build. Similarly, it may prevent the need to run a gas line or whathaveyou (because electric heat wouldn’t be cost-prohibitive at that point) and you could just do solar hot water..

        I’m looking fwd to learning about your experience.

  4. Andrew Evans

    My neighbor and I were talking about that, and it’s been on my radar ever since buying our house 5 years ago. Our car family right now is at 3, and we’re (well mostly me) thinking about adding a 4th or replacing the winter car. It’d be nice to have a two story heated garage, with a loft, a bathroom, and one lift so the car in storage can be out of the way.

    From the discussion I guess the big points are the height requirements to the house, space between the house and the garage, and then the added cost with running plumbing. I’m lucky in that my house is basically 3 stories (counting the attic) and there should be enough room between the buildings where I wouldn’t be doing anything outside of the norms.

    The ballpark quotes I’ve got were anywhere from 3 to 4 times the cost of building a garage, depending on how much finishing work I do. Also, that the city will want to see plumbing working and in place in a given timeframe, which also means the space needs to be heated, so its’ not something that a person could leave roughed in. Although I guess this could be “cheated” with a ground floor bathroom, leaving the 2nd/loft unfinished. It also could be helped if in floor heating and/or drains are desirable or not, to limit any additional plumbing or insulation.

    I guess it really comes down to need and value. Although uncommon mother-in-law spaces aren’t new, and the zoning has been changed for a while now. It seems like this type of building will work for the author, and may be worth that extra cost, however for me it may be worth renting a garage space somewhere (like a hobby/studio space) and doing my projects and storage there. For an average person, I’m not sure how it could be worth the additional expense. I’m not sure about resale values off hand, I’m sure it would be worth something more than a garage, but not sure if it would, on it’s own, make up for the cost of building.

    FWIW since someone mentioned solar heat without running gas… That isn’t the expensive part. A gas and electric line, as far as I know, can use a regular standard trench. They are also easy to route from an existing basement with only a small hole for the pipe or conduit. The expensive part is running plumbing, which will either need to tie into the homes system, or be ran out to the street or sewer hookup. This needs to be below frost line, and is a much larger undertaking. It also requires that the building be heated by a standard reliable means, so I’m not sure the city would go for solar heating and sign off on a plumbing permit without another means of heat.

    This ties in with the value of the project. For the author they will receive enough use from the additional space to make up for the cost. For me, it could mean I don’t need to spend 5 to 10 thousand a year on renting a shop space for my cars and projects. For an average person though, with no need for an office, studio, or storage, that additional cost may not be worth it – which may be why these aren’t as popular.

    1. Andrew Evans

      [edit – kinda]

      Getting sick and my brain may have shut down a little before.

      If the author is talking about having a studio or walling off one side of a garage, then it would be cheaper. Although plumbing would still be a pretty large undertaking if it was desired.

      Usually, at least in the circles I run in, these are always two stories with the apartment above the garage, so my mind skipped to that right away.

      1. Brit AnbachtBrit Anbacht

        You are correct here. I will get into this more later but we are talking about replacing the current garage with a new building having a different orientation and 1-2 garage spaces, adding an office space on the first floor and an apartment on the second floor.

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