Before I answer the question, what legally is the smallest house you can build in Texas, I want to point out that I’m not a lawyer and it’s always best when dealing with anything legal to consult a real lawyer.
That being said, I’ve done a lot of research on the subject matter and here is what I’ve found.
The quick answer is about 200 square feet, based on the International Residential Code (IRC). But there are other things to consider …
All homes, no matter how big or small are subject to building and safety regulations.
For your reference, here is a quick link to the Texas Administrative Code regarding homes on wheels.
A tiny house on wheels (in Texas) that is less than 400 square feet is what the state calls a house trailer and falls under the RV laws.
Your tiny house on wheels must be certified by the American National Safety Institute (ANSI) to meet the personal property tax exception rules. If you are buying a pre-built tiny house on wheels, make sure it is certified by ANSI.
If your tiny house is on wheels, don’t forget you must register it as an RV (recreational vehicle).
If your tiny house is built on a foundation and not on wheels, it’s considered real property and subject to property taxes just like any regular house might be.
This tiny home will be subject to local building code regulations. Although it’s worth noting, most rural areas in Texas have no local building codes.
Building codes means getting permits and lots of inspections. In fact, for new residential construction on a vacant lot, a minimum of three inspections must be performed during the construction project to ensure code compliance, That’s in addition to contractor inspections for things like electrical and plumbing.
This can be time-consuming and costly. This is why so many people prefer building their tiny house on wheels.
If you don’t comply with all building regulations the county in which you build in could actually fine you a daily fee, until you get in compliance (Could even be $1,000 a day) or require you take the building down altogether.
Some towns in Texas like Spur, Texas encourages the building of tiny homes, but you must submit your house design in advance for approval and agree to connect your home to the electric grid and town’s water and sewage system.
There is a thing called the IRC, or the International Residential Code. Here are some highlights…
- R304.2 Other habitable rooms shall have a floor area of not less than 70 square feet (except kitchens)
- R304.3 Habitable rooms shall not be less than 7 feet in any horizontal dimension (except kitchens)
- R304.4 Portions of a room with a sloping ceiling measuring less than 5 feet between floor and ceiling shall not be considered as contributing to the minimum required a habitable area for that room.
- R306.1 Requires that every dwelling have a water closet, lavatory, and bathtub or shower (which could be as small as 18 sf while still meeting spacing requirements in Section 307)
- R306.2 Requires that every dwelling have a kitchen area with a sink
Previously they said that every house has at least one habitable room that is now less than 120 square feet of gross floor area. This was however removed from the requirements in 2015.
So if you build a tiny house, that is laid out like a traditional home, it could be as small as 208 square feet and still be legal.
- Bedroom: 70 sf
- Living room: 70 sf
- Kitchen: 50 sf
- Bathroom: 18 sf
Austin, Texas legally defines a “Tiny House” as …..
A tiny house is fairly self-descriptive: it is a very small dwelling unit that is free-standing, usually styled to look like a site-built home. Tiny houses typically range from 100 to 400 square feet in size and often come mounted on a wheeled trailer chassis so that they can be towed behind a vehicle. Similar to a micro-unit, the space in a tiny house usually has convertible or modular furniture that plays different roles, depending on what activity is taking place. Tiny houses on wheels typically have recreational vehicle-style utility hookups – powered with electricity, external holding tanks; those that venture off the grid can rely on solar or even no electricity at all. Diminutive domiciles that are permanent structures (not on wheels) tie-in to utilities in the manner of a traditional house. Tiny houses should not be confused with mobile homes, which are generally more than 600 square feet in size, and are transported via semi-trailer truck to a destination where they are placed permanently or semi-permanently.
In Austin as long as you get all the proper permits and go through the correct inspections, etc. as any new build would, they don’t seem to care how small the house is (as long as it follows the rules of the IRC).
In Dallas, tiny houses are often referred to as “granny flats”, “granny pods” or “mother-in-law cottage”. They are legal only if you apply for a special exemption and they don’t violate your property’s homeowner association’s rules.
But keep in mind this is talking about building a tiny house on a property that houses a main, regular size house. The regulations aren’t clear about building a tiny house as the only house on the land.
So just how small is too small in Texas?
It’s actually the HOA that could be a big problem for most Texas cities. As long as you follow IRC rules, I have found most places in Texas who have rules, and building codes, don’t care about actual size and don’t even reference size restrictions when you get your permit.