Road Limits for Tiny Houses on Trailers

Building a tiny house on a trailer is one way to avoid certain limitations that are often unavoidable when building on permanent foundations. For example, while building codes can be a great guide for building a safe home, I’ve never heard of a planning department expressing any desire to examine a tiny house on a trailer.

It makes sense actually – tiny houses on trailers can move to and from different communities; who would inspect them? The truth is tiny houses exist in a grey area between traditional houses and travel trailers.


But this scale of home is not entirely without limits. If you want to be able to pull your house down a highway without a special permit, it must conform to certain size limits. In most U.S. states this maximum size is 13.5-feet tall, 8.5-feet wide, and 40-feet long – 65-feet maximum including the tow vehicle. Extra care must be taken to squeeze the house into this semi-trailer sized imaginary space.

Below is a simple drawing that shows how quickly everything adds up. You can instantly see why so many tiny houses have roof pitches that are no steeper and 12/12 (45-degrees) and walls that are a bit shorter than 8-feet. At first the design challenge seems daunting, but as you browse through all the different homes people have built, you can see that there is still quite a bit you can do within the box.


Commercial travel trailers are designed to be lightweight and aerodynamic. Tiny houses are typically built from heavy building materials, like normal houses. This can make it much more comfortable to live in year-round but every foot in length adds-up and increases the requirements for the trailer and tow vehicle.

For example, a Tumbleweed Fencl is about 19-feet long and weighs just shy of 6,000 pounds empty. Add your belongings and you might start pushing 8,000 pounds. Now theoretically double the length to the 40-foot road limit – you could be talking about a house that weighs 16,000+ pounds, which would require a really big pickup to tow. This is not unthinkable of course, they build pickup trucks that can pull trailers that size; but it is an important consideration to make before committing to that scale.


Building tiny houses on trailers can provide a lot of flexibility and freedom; but like every design challenge, it doesn’t come without trade-offs. While you may not have to talk with building inspectors, you are pretty much on your own to build a safe and strong home on your own.

It’s best to use building codes as guides and add extra reinforcement like earthquake and hurricane straps – after all the house will encounter 60 MPH winds and road vibrations. For some this may sound adversely challenging – to others it sounds like music to their ears. In either case try starting your design process from these practical size and weight limits.

If you decide to build a tiny house I’d love to share your story here on Tiny House Design. I also strongly encourage you to get a free blog at or and journal about your experience. We’re stronger together.


  1. S

    Mike, you must have been reading my mind! Thanks so much for the article and diagram. I was wondering how high off the ground typical trailer flatbeds are — certainly don’t want to tow something higher than the 13.5 foot limit and wind up with a partially missing house!

    I’m also really looking forward to that upcoming “ultralite” design you’ve been tinkering with. Perhaps that would allow for a lighter and less expensive trailer then?

    I’m hoping to finally get started on my own “tiny house” project by sometime next year. My goal is to be able to cook, do laundry, have enough storage for my stuff, and have a friend or two over for lunch, all in around 100 square feet — difficult I know, but not impossible! I’ll keep you posted — and thank you so much for being such an inspiration to us, your readers! You’re one person who’s really got me excited about going forth with my project!

  2. S

    One thing that I found out when doing some research is that New York state restricts how many pounds you can haul to 10,000 if you just have an average drivers license. Not sure what it is for other states, but it is something to consider if you do not want to pay for an upgrade to your drivers license.

  3. N

    This is the law for a class D license in NY:

    May tow a vehicle with a GVWR of 10,000 pounds or less; or may tow a vehicle of more than 10,000 pounds providing the GCWR is not over 26,000 pounds

  4. a

    It’s amazing how much you can fit in a space if you design the storage from scratch according to exactly what you need. Once you decide what’s staying the next part is figuring out how to keep it stored but easily accessible. The less you have to move to get at other things the better – keep things containerized so you only have to move 1 piece to get behind it instead of several loose items. You can design cupboards around your storage containers rather than trying to find something later that might waste several of those critical inches. It’s amazing where you can fit a narrow pullout/foldout cupboard that lets you see all its contents without rummaging. A lot of the frustration in small space living is due to poor storage access.

  5. G

    My boyfriend and I are building and designing a 34′ travel trailer we hope to power by solar. we are used light gauge steel framing to build the walls. the whole structure, after sided etc, will only weight about 3,000. steel offers great strength to weight ratio, and also cuts down on flammables in a vehicle that will contain propane use and also the batteries for the solar system.

  6. S

    I am considering building a trailer abut the same size you are with steel framing. How is your build going?

  7. J

    How has it gone, so far? I’m very concerned about final-built weight…

  8. K

    Anything on the weight?

  9. S

    I know this is 5 years too late, but I was wondering how everything turned out with your 34′ travel trailer. My wife and I would really like to build our tiny house on a 32′ trailer. My only real concern is taking it onto the highway to its semi-permanent location. If I need to, I can have my father drive it since he has a CDL, but I was just wondering if it was very difficult to take on the interstate and how much yours ended up weighing. Thanks!

  10. S

    I am looking for more info on width allowances for permitted moves. As I see it, the major advantage of building on a trailer is to avoid the building inspectors and not that I want to move all around the country that often! If I wanted to move that often I would just buy a recreation trailer. So, maybe I can build wider than 8’6″ and just get a permit with a wide load escort. How much wider? I am talking about something like how they trailer manufactured home halves, not a full road closure move.

  11. E

    Stop at any truck stop and for about 8 bucks you can buy a Rand McNally road atlas. This is a guide for truck drivers.It will have all the laws broken down by state that would affect your heights, and weights. It will tell you where all low clearances and bridges with weight limits and axle limits. It also has the number in each state you need to call for wide loads getting permits and escort vehicles. It even has a map of all the states and some larger cities. Hard to believe you can get all that for just 8 bucks, save a lot of time asking questions to people who don’t know much more than you.

  12. B

    We spent 4 years living, and on/off traveling, in a 37 foot fifth wheel. We are seriously considering turning our trailer into a tiny house. We have found that most RV s are not made for fulltime living. The biggest issue is condensation. We now have roof damage as well as mold. This in a 2006 model that was only used 3 weeks wen we purchased it. One thing we found with under passes and bridges, is that the posted max height may not be accurate due to the resurfacing of the road.

  13. J

    I too have been thinking the same thing Steve. In fact I am in the process of designing a tiny house that will exceed the height and width maximums used by most tiny houses.

  14. S

    FYI, just looked up regulations in Washington state – $10 special permit fee you
    can get a permit to move a “park trailer” which exceeds the standard width(8’6″) limit. A good place to start, if interested, is RCW 46.44.092 – Special permits — Overall width limits, exceptions — Application for permit.(14ft & 16ft daylight hrs max)
    And FYI, the height limit is 14 feet in Washington State.

  15. C

    Thanks, Steve. That was most helpful info.

  16. Does anyone know if you would need a special license to tow a 20′ or 22′ long trailer?


  17. D

    Typically there is no special limit based on length unless your total vehicle length (including tow vehicle) is over 60 ft. The biggest requirement is the length and height. However to drive with a standard drivers license there are weight limits and those can vary depending on the state/ province, so be sure to look into it before building

  18. b

    Nope you can tow up to 52 foot trailer

  19. E

    Its not the length of the trailer that will require the cdl, its the weight. 26,000 lbs is the most you can weigh, 1 more pound will require a cdl. This is any combination, and the towing vehicle has to be under 10,000. So if you using a truck the is 7000 lbs, you would be able to haul a 19,000 lb trailer. Keep in mind adding fuel to a tank, or more people in a vehicle, will add weight so leave yourself some wiggle room. Trucks have been shut down because they fueled after weighing and hit a scale not thinking about the extra weight. Also brakes, air brakes require an endorsement, this is why a 26′ box truck can be non cdl but a 16′ could require a cdl. This article says 40′ is the max length of a house trailer. It says a tumbleweed that’s 19′ is about 6000 and with belongings about 8000, so figure how much its weighing per foot, 8000/19=422×3=1264, so another 3 feet should bring you to about 9264 lbs… But yours will be different for sure but leaves plenty of room so you should have no problem staying legal.

  20. D


  21. l

    which one would be good to stay into US code? 7×12 8×12 8×14 8×16.


  22. The road limit is 8’6″ wide and 13’6″ tall. The length is something like 40 feet depending on the state.

  23. z

    The trailer length is not generally regulated by any state in the US. It’s regulated by the DOT. I’m truck driver and these are basic laws every trucker needs to know. The length that states do regulate are when you haul double and triple trailers and/or are going into cities like NYC that are restricted to 48ft. If on city streets. All states require a CDL to haul any vehicle that has a gross combination weight (truck and trailer weight fully loaded) of 26,001lbs our more. The dimensions are spot on. No greater then 13’6″ tall and 8’6″ wide. If you go over that you will typically need a OD(over dimension) permit to haul. When in doubt call your state highway patrol and will inform you of the regulations you need to be aware of.

  24. z

    Oh forgot to mention the trailer length is 52′ unless you’re taking it into a city that requires 48 our less.

  25. D

    What are we building a tank?My home trailer build with 1×1 & 2×2 70 feet x 10 feet. Tiny house 8×18 building ultralight out side wall 3/8″ – 4’X8′ T1-11 in sid wall Maple Plywood (Common: 1/4-in x 4-ft x 8-ft 2×4 wall you could make Engineered wood floor trusses I-joist 1×1 with 1/4 Plywood or 1-in x 4-in wood

  26. S

    I really wanted to have a wider tiny home…semi’s are 10-11 ft wide…can’t you build a tiny home that wide? I wouldn’t build longer than 40ft so it wouldn’t be the full size of a semi….would l be able to do that without a permit or cdl?

  27. D

    Does anyone know the requirements for towing a 10.5’wide x 20′ long and 13′ high tiny home. Since the issue here is width (10.5 feet instead of 8.5m feet) do you need pilot vehicles and signage?


  28. D

    Never mind. I found the North Carolina DOT OVERSIZE/OVERWEIGHT PERMIT HANDBOOK.. and states on page 17 what is needed for 10 foot wide.

  29. A

    This is if the tiny house is built ON a trailer. What if it is built like a regular home and then hitched to ship it to its destination? Would it be better to at that point just build it on the property?

  30. D

    Can you put a portable building, on a trailer, to use as your exterior TINY HOME?????

  31. Theoretically yes, but I can’t think of ever seeing one built that way.

  32. D

    I wondering the same thing! I have been looking at nice portable buildings and thinking I could put it on a trailer and then design the inside, insulate, etc. So, you’re saying that is do-able?

  33. R

    i was wondering if you could post a 3 bedroom 1 or even better 1 1/4 (extra toilet closet) design or ideas…. Been sketching but very little available for a family of 5. (2 boys 6 and 7, and a 16 year old girl). Husband thinks I’m a little nuts but willing to entertain it if I show him how I can make it feasible. My idea is a small single room over truck bed with a bottom entry in front of a loft/bathroom area. But ANYTHING designed for a 3 bedroom area would be awesome! Thanks for the measurements, it helps my sketching in the meanwhile!

  34. D

    And no … I am not the same Deborah that asked that first question, although Deborahs must think alike!! lol

  35. 8

    I am considering your finished trailer how it gonna be look like. Your measurement and size of your trailer seems very fit to your desired trailer. Expecting a much greater work and outcome from you.

  36. W

    Have a tiny house in Strasburg Ohio, and looking for someone able to move it to Yakima Washington.

  37. F

    There is a bi-product of insulated steel panels which are the drops from where they cut out a slab door to put in a full glass this leaves a piece of foam with a steel skin on both sides then they route the foam allowing them to interlock. Then they screw the skin together and build walls with no studs or framing. They are 22×64 inches. 1 3/4 inch thick and are supposed to be r-19. These save space on your floor and are stronger and weigh 12 pounds per panel. You can see the buildings at tri-county insulated buildings Corbin ky. I don’t work there or anything. Just used them before and thought about the small house thing

  38. j

    My husband happens to have a CDL. What size trailer can he pull with his CDL, but without having to have a permit?

  39. It depends on the state. I don’t know how the type of license changes things. Typically 8.5′ wide, 13.5′ tall.

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