Tiny Tuesday: A Guide to Minimum Square-Foot Laws

Small-living proponents often lament that occupancy laws make tiny houses and micro-apartments illegal. Specifically, most jurisdictions have a minimum square-footage law for permanent dwellings. (One reason tiny houses are often built on wheels is not to make them mobile but to classify them as travel trailers instead of dwellings.) But I haven’t found any compilation of what those laws actually are. So I started one myself.

The US has adopted the International Residential Code, which isn’t all that limiting: the floor area of a “habitable room” (any room in the house except a bathroom, kitchen, closet, or utility room) may be no less that 70 square feet. There is no minimum number of habitable rooms in a dwelling. The limitations increase as you zoom in, though. States may issue supplements to the IRC or reprint the code entirely. Cities add their own cutoffs, and neighborhoods may have zoning requirements that push the minimum even higher.

This reference is incomplete. I intend to grow it as I continue my research.

IRC: Minimum one 70 SF habitable room. See 2015 IRC R301.1.

Arizona: Phoenix requires a minimum of one 120 SF habitable room. See 2006 Phoenix IRC R304.1.

California: Minimum one 70 SF habitable room. For an efficiency dwelling unit, the minimum total floor area of 220 SF. See 2016 California Residential Code R304.1 and R305.1.

Florida: Minimum one 120 SF habitable room. See 2014 Florida Residential Code R304.1 .

Indiana: Minimum one 120 SF habitable room. See Indiana Residential Code R304.1.

Massachusetts: The minimum size of a single-occupancy studio is 150 SF. See 105 CMR 410.400(A).

Michigan: Supplement to the IRC does not amend minimum SF.

Minnesota: Supplement to the IRC does not amend minimum SF.

New Jersey: Minimum one 70 SF habitable room. See 2015 IRC New Jersey edition, R304.1.

New York: Uniform code supplement to the IRC does not amend minimum SF. New York City requires a minimum of one 150 SF habitable room. See Housing Maintenance Code D26-33.01.

North Carolina: Minimum one 120 SF habitable room. See 2012 North Carolina Residential Standards R304.1.

Ohio: Minimum one 120 SF habitable room. See Ohio Residential Standards 4101:8.3 304.1.

Oregon: Minimum one 120 SF habitable room. See 2011 Oregon Residential Specialty Code R304.1.

Pennsylvania: Supplement to the IRC does not amend minimum SF.

Rhode Island: The minimum size of a dwelling is 150 SF. See Housing Maintenance and Occupancy Code 45-24.3-11.

South Carolina: Supplement to the IRC does not amend minimum SF.

Vermont: Burlington requires a minimum dwelling size of 150 SF. See Charter and Related Laws 18-90.

Virginia: Minimum one 120 SF habitable room. See 2012 Virginia Residential Code R304.1.

Wisconsin: Supplement to the IRC does not amend minimum SF.

Washington: Seattle requires a minimum of one 120 SF habitable room. See Seattle Residential Code R304.1.

Tiny Tuesday: A House in Search of a Home

Jesse lives in a 180-square-foot house on wheels in Vermont’s Mad River Valley. It was built by a Yestermorrow Design-Build School class, and demonstrates what a tiny house can look like when it’s not staged but actually lived in.

From the front porch, you enter into a mudroom with ample storage space to the left; on the right a sliding door opens on a fairly cramped bathroom. Beyond, a wide corridor kitchen with marine-grade appliances opens onto a full-height volume, with a couch that doubles as a bed along the back wall. Upstairs, twin dormer windows offer headroom to the loft which covers two thirds of the footprint.

Jesse’s house works in large part because of multifunctional spaces. A table and chairs for eating or working fit neatly within the full-height great room, then fold down to almost nothing. The same space is used to access the loft via a ladder which pivots up out of the way when not in use. The bottom is hinged to rest on a wall cleat above head height – a clever solution to the visual and physical space problem of a permanent stairway.

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Part of the kitchen, with an alcohol-burning cooktop and a folding table (yes, there’s chairs in there too).

A tiny wood stove is more than adequate to heat the building; last year got Jesse through the winter on a third of a cord of wood. A sliding door in the corner of the back wall allows him to move wood from outside directly to the stove. He runs his plumbing off a 50-gallon tank that lives right next to the kitchen sink. In terms of legality, Jesse opines that greywater is the biggest problem. Composting toilets are perfectly legal, but no substitute exists for sinks and showers: they need to drain to a septic system or town sewer.

Jesse is in search of a permanent piece of land for his house. For now, he has taken up residence in the backyard of a friend, who runs an electrical cable from the big house to the little one. (Jesse also has PV panels he can set up to live off-grid.) He showed me his VTrans permit from when he last moved the house about a month ago. Its road width just exceeds the 8’-6” maximum for towing without a permit; it’s about 22 feet long and under 13 feet tall when the smokestack is removed. He’ll need to move it again before winter.

If you live in the Mad River Valley and you’d like to host a small house with an awesome occupant, please drop me a line!

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Back wall with bay window, utility compartment, trailer hitch, and wood stove access at the lower right.

Tiny Tuesday: Finance Your Dream

Last week  I wrote about luxury tiny houses. Today’s article is for the other 99%.

The term “homeowner” is misleading. For most people, the only way to buy a house is to go deeply into debt, and then spend 15 to 30 years paying off a mortgage (if you even keep the house that long). According to this article on fivethirtyeight, only 1 in 3 owner-occupied homes in the US is mortgage-free.

Accessible mortgages are a good thing – they enable a far larger population to own homes – until many people find themselves incapable of paying off the loan. This fact basically caused the world economy to collapse in 2008, leading folks like Ryan Mitchell to pursue alternative living options. I covered Ryan’s story in a previous post, and I don’t have to point out the economics of buying a tiny house versus a conventional-size one. Can somebody who doesn’t qualify to buy a regular house get a mortgage for a tiny house?

Unfortunately, no. Ryan returns in this USA Today article explaining that, for many small houses, the options available to big house buyers simply don’t exist. Lenders set a minimum principal for their mortgages, and properties on wheels are often excluded. If a low-principal mortgage does exist, it’s likely to have a high interest rate. The reason for the rate is actuarial – most houses worth under $50,000 are manufactured homes, and manufactured home owners tend to have a less stable source of income, making them risky loans for the lender. (Remember, it was a glut of precarious mortgages that brought the Great Recession.)

Other options exist. If you are building your tiny house from scratch, instead of buying one that’s already built, you might get a builder’s loan. Or you can get a personal or unsecured loan which lacks the collateral of the house, making it even riskier for the bank and carrying an even higher interest rate. The USA Today article names a few lenders that cater to small houses and provides sample quotes. It’s useful information for the would-be homeowner.

Thanks to Peter Roth.