Say I’ve bought an empty lot where a house was torn down. And let’s say I decide I don’t need a full-size house; a one-room cabin the size of a large garage with a toilet stall in one corner will do me fine. YMMV, but generally what’s the smallest dwelling most city codes would allow you to build and occupy? (Provided you have electricity, water, sewer, etc. hooked up)
300 sq feet small enough?
There’s no standard answer to this. Building codes vary widely from location to location.
A Tumbleweed Tiny House would seem to fit your bill. The smallest one is 65 square feet.
Many jurisdictions allow dwellings under 200 sq. ft. to be built without a permit, though in California it is 10’x12’ with no plumbing or electricity.
If you are interested in buildiing a small house, an excellent resource is www.countryplans.com, which specialiazes in plans for small, owner built houses. They have an active forum of owner builders who share ideas and experiences.
I don’t think there is a code size restriction. The city simply wants it built well.
Now, some home owner associations have a minimum size. My neighborhood requires at least 1400 sq feet with a carport or garage. The requirements are explained in the bill of assurance.
So, be sure to buy in a neighborhood that doesn’t have an active home owner association. Have the Realtor check the bill of assurance for any restrictions.
In Ontario, you don’t need a permit if you’re building under 10 square metres, and the building has no plumbing or sewerage. However… some municipaities may forbid larger structures.
For Minneapolis see here
Minneapolis, Minnesota Building Codes
and here
Zoning
In looking at your residential zoning code your main issue is going to be the minimum 5,000 sq ft lot requirement for a single family residence. It does not speak to minimum house size, only minimum lot sizes.
This video shows some of the problems of living in too small a house.
How big was the Unibomber’s shed?
Basically a shed from Home Depot (Home Depot makes much nicer sheds).
:eek: no plumbing?? For a residential house?
I can’t see that being allowed. They don’t want people using the back yard as a toilet. That’s a health hazard for the entire neighborhood.
Allow me to also point out that, at the discretion of the Zoning Board, someone owning a pre-existing lot too small to fit a house meeting minimum lot size requirements is entitled to a variance to make use of his/her lot. This is probably a place where consulting a lawyer specializing in land use would be advisable. I’m fairly sure that the right to seek (and be granted given reasonable grounds) a variance is part and parcel of the case law that established zoning laws as constitutional in the first place, so this would be relevant anywhere in the U.S.
I think most tiny houses us RV style plumbing connecting to a sewer hose or a tank. Composting toilets are also an option, as are connecting to a septic system. In some cases- such as when a tiny house is built into a backyard, I imagine they simply use the house toilet for defecating.
Running water is not that big of a deal if you have access to a tap somewhere and don’t mind doing a bit of hauling. In more remote areas you can have water tanks or rainwater tanks.
Gaagh! Legally required urban sprawl. My house, in a fairly posh neighborhood whose houses and lots are generous, is on a 5000 square foot lot. But the house I grew up in, a pretty standard Philadelphia row house, was on a lot that couldn’t have been larger than 2500 square foot.
At McGill a member of the architechture dept built on campus something he called a “grow home” that was 14’ wide and maybe 20’ long. It had a living room, bedroom, and kitchen on the first floor, a bathroom on the second. The rest of the second floor was unfinished, but the idea was that it could be. So the total floor area was under 600 square foot. It turned out the Montreal building code did not allow a house 14’ wide.
Saw a NYC apartment that was very small, they had no room for any kitchen stuff other than a microwave and a small sink. I think it was around 200 square feet. They had a tiny bathroom and shower.
I’ve been in a NYC apartment that instead of having a bathroom had a small water closet (ie a toilet in a closetsized room) and a bathtub in the kitchen! :eek: The tub came with a cover you could set stuff on like a shelf, but the tenant prefered to put a curtains in front of it to hide the whole thing from view (though this made the kitchen seem even smaller and blocked it’s window). It wasn’t a studio either. Three rooms counting the kitchen, all in a row. The 1st room (which had the entrance) was set up as a living room, the 2nd as a bedroom (this was also where the WC was), and the 3rd was the kitchen.
I’d suggest looking into modern tree houses. Some of them are incredible. They are tiny houses with small sq footage.
They aren’t much harder to build. They are built from a free standing deck that isn’t attached to the tree. On top of the deck goes the walls, windows and roof. They usually are just a few feet off the ground. Some are way high. Depends on what you like and the size of the tree. 
these are real, year around homes.
Actually, I think the under-10-m[sup]2[/sup]-without-plumbing exception is intended to allow the construction of things like garden sheds without too much bother… and even if you just put an outhouse nearby, that needs a septic permit and many municipalities forbid them.
If it’s a farm building, not intended for human occupation, the looser Farm Building Code applies.