Tiny house permits, explained
A tiny house you live in on a permanent foundation needs a building permit like any home, usually under the International Residential Code's tiny house appendix for dwellings of 400 square feet or less, excluding lofts. A tiny house on wheels is often treated as a recreational vehicle, which many zoning codes do not allow as a year-round home.
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- Albion, Idaho, which adopted a tiny house ordinance in 2025, requires building permits to residential building code standards for each tiny house, a permanent foundation, and connection to city water, sewer and electrical utilities.[3]City of Albion, Idaho, Ordinance No. 2025-06-01, Tiny House Regulations
- Boise, Idaho, states that tiny house construction uses its one- and two-family dwelling code unless the tiny house appendix says otherwise, and that tiny houses need to be on a permanent foundation.[1]City of Boise, Idaho, Planning and Development Services, Tiny Houses
- The appendix applies only where your state or city adopts it: its own text says its provisions are not mandatory unless specifically referenced in the adopting ordinance.[2]City of Seattle, 2021 Seattle Residential Code, Appendix AQ, Tiny Houses
- Washington's version, published by Seattle, sends loft ceiling heights to Section R326 of the main code instead.[2]City of Seattle, 2021 Seattle Residential Code, Appendix AQ, Tiny Houses
- Boise notes that motor homes, travel trailers, fifth-wheel trailers and park model RVs are recreational vehicles designed as temporary living quarters for recreational, camping or seasonal use, not as year-round dwellings.[1]City of Boise, Idaho, Planning and Development Services, Tiny Houses
Do you need a permit for a tiny house?
The question splits in two, and the answer depends on what the house stands on.
| Your tiny house | How it is usually treated | What you need |
|---|---|---|
| On a permanent foundation, lived in | A dwelling, under the residential building code | Zoning approval, a building permit, utility connections, inspections |
| Built in a factory to a state program | A modular or state-certified home | State approval of the unit, then a local permit to place it |
| On a trailer, with wheels and a hitch | Often a recreational vehicle, unless the city has a specific rule | A place where zoning allows it to be lived in |
A tiny house you live in on a foundation is a house. Albion, Idaho, which adopted a tiny house ordinance in 2025, requires building permits to residential building code standards for each tiny house, a permanent foundation, and connection to city water, sewer and electrical utilities[3]. Boise, Idaho, states that tiny house construction uses its one- and two-family dwelling code unless the tiny house appendix says otherwise, and that tiny houses need to be on a permanent foundation[1].
The building code: the tiny house appendix
The International Residential Code (IRC) has an optional appendix written for very small homes. It was Appendix Q in the 2018 edition[6], Appendix AQ in the 2021 edition, as Seattle's code shows[2], and is Appendix BB in the 2024 edition[5]. Its core definition is the one most cities use: a tiny house is a dwelling of 400 square feet or less in floor area, excluding lofts[2][1].
The appendix does not create a separate, lighter house. It relaxes specific rules that are hard to meet at this size, and the rest of the code still applies[2]. Boise summarizes what it relaxes[1]:
- Ceilings: habitable space and hallways at least 6 feet 8 inches; bathrooms, toilet rooms and kitchens at least 6 feet 4 inches; lofts may be lower.
- Lofts: a floor more than 30 inches above the main floor, open to it on one or more sides, used for living or sleeping, at least 35 square feet and 5 feet in every horizontal dimension.
- Loft access: compact stairs, ladders, alternating tread devices or ship's ladders, within the appendix's limits.
- Guards: along the open sides of a loft, at least 36 inches high or half the clear height to the ceiling, whichever is less.
- Egress: the house still needs emergency escape openings; a roof window can serve a sleeping loft if the bottom of its opening is no more than 44 inches above the loft floor.
Two cautions. The appendix applies only where your state or city adopts it: its own text says its provisions are not mandatory unless specifically referenced in the adopting ordinance[2]. And adopters amend it: Washington's version, published by Seattle, sends loft ceiling heights to Section R326 of the main code instead[2].
Zoning: can a tiny house go on your lot?
The building code tells you how to build it. Zoning tells you whether you may put it there, and this is where most tiny house projects stop. Albion's ordinance is a clear example of what a city can require[3]:
- a conditional use permit in the zones where single-family dwellings are allowed;
- its own lot, with the zone's setbacks and development standards;
- a permanent foundation and connection to city water, sewer and electricity;
- two off-street parking spaces per tiny house;
- compliance with the International Fire Code, including fire access.
A tiny house as a second home on a lot that already has a house is usually reviewed as an accessory dwelling unit instead, under the city's ADU rules. See the ADU permit page.
Tiny houses on wheels
Wheels move a tiny house out of the building code in many places. Boise notes that motor homes, travel trailers, fifth-wheel trailers and park model RVs are recreational vehicles designed as temporary living quarters for recreational, camping or seasonal use, not as year-round dwellings[1]. Albion's ordinance excludes recreational vehicles, park trailers and tiny houses on wheels from its tiny house definition, and requires those used as dwellings to be in an approved RV park[3].
Some cities have opened a path. Since July 1, 2025, Boise allows tiny homes on wheels in some zoning districts, defined as transportable accessory structures on a chassis with hitch and wheels, under 400 square feet, with independent living facilities, certified to the NOAH+ standards or other standards the city adopts, and not including RVs[1].
Factory-built tiny homes
A third route runs through the state. In Colorado, the Division of Housing approves the plans of state-certified "Tiny Homes" before they are built; the state says they are approved for long-term living like modular, HUD-code and mobile homes, that they have a permanent chassis, and that they can go on a permanent or temporary foundation[4]. In Boise, tiny houses built as modular or manufactured homes must be permitted by the state and by the city before being placed on a foundation, and anything built on site needs plan review and a building permit[1].
What the permit file includes
For a site-built tiny house on a foundation, expect the file of a small house: a site plan with setbacks and utility routes, floor plan, sections and elevations, the foundation, the loft and its access, the egress windows, and the plumbing, electrical and mechanical layouts, plus the zoning approval first. Boise asks applicants to check with its planning and zoning division before submitting for a building permit[1].
Building or parking it without approval
The risk with a tiny house is not a fine for a missing deck inspection: it is being told you cannot live in it where it stands. Albion's ordinance states that no tiny house or park model will be placed on any property except as permitted by its city code[3]. The common refusals, and what they cost, are on why tiny house permits get rejected.
Tiny houses are larger projects than our All-in offer covers, so we quote them individually: tell us your address and your plans, and the quote lists your city's real rules and published fees before you commit.
Common questions
Do you need a permit to build a tiny house?
Yes, if it is a dwelling on a foundation. It is built and inspected like a house, with the relaxed rules of the code's tiny house appendix where your jurisdiction has adopted it. Albion, Idaho, for example, requires building permits to residential building code standards for every tiny house.
What size is a tiny house under the building code?
The model appendix defines a tiny house as a dwelling of 400 square feet or less in floor area, excluding lofts. Boise, Idaho, uses the same definition.
Is a tiny house on wheels legal to live in?
It depends on the city. Many codes treat it as a recreational vehicle meant for temporary or seasonal use; Albion, Idaho, requires RVs, park models and tiny houses on wheels used as dwellings to be in an approved RV park. Boise, Idaho, has allowed certified tiny homes on wheels in some zoning districts since July 1, 2025.
What is Appendix Q?
The tiny house appendix of the International Residential Code. It was Appendix Q in the 2018 edition, AQ in the 2021 edition and Appendix BB in the 2024 edition. It relaxes ceiling heights, loft access and some egress rules for houses of 400 square feet or less, and only applies where a jurisdiction adopts it.
How much does a tiny house permit cost?
Fees are set by your city or county, from its published fee schedule, and depend on the route: a building permit for a house on a foundation, a placement permit for a factory-built unit, sometimes a zoning or conditional use application first. Your quote lists the published fees for your address before you commit.
Let us prepare your tiny house permit
We research the rules that apply at your address and tell you exactly what your city needs before you commit to anything.
Sources
- City of Boise, Idaho, Planning and Development Services, Tiny Houses. Checked October 13, 2026.
- City of Seattle, 2021 Seattle Residential Code, Appendix AQ, Tiny Houses (with Washington amendments). Checked October 13, 2026.
- City of Albion, Idaho, Ordinance No. 2025-06-01, Tiny House Regulations (passed June 3, 2025). Checked October 13, 2026.
- Colorado Department of Local Affairs, Division of Housing, Tiny Homes and Tiny Houses Information Center. Checked October 13, 2026.
- International Code Council, 2024 International Residential Code, Appendix BB, Tiny Houses. Checked October 13, 2026.
- International Code Council, 2018 International Residential Code, Appendix Q, Tiny Houses. Checked October 13, 2026.