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.

Size

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.

Weight

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.

Freedom

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 WordPress.com or Blogger.com and journal about your experience. We’re stronger together.

14 Comments Road Limits for Tiny Houses on Trailers

  1. Steve W.

    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!

    Reply
  2. Sarah L

    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.

    Reply
  3. alice

    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.

    Reply
  4. Gretchen Elsner

    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.

    Reply
    1. Scott

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

      Reply
  5. Steve

    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.

    Reply
  6. Steve

    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)
    http://apps.leg.wa.gov/RCW/default.aspx?cite=46.44.092
    And FYI, the height limit is 14 feet in Washington State.

    Reply
    1. Doug

      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

      Reply
  7. DAVE DUCKETT

    CONTRACTORS USE A 1/8 SHEET OF PLASTIC THAT IS VERY STRONG COME IN 4 X 8 SHEETS AND WEIGHTS JUST OUNCES AND VERY STRONG COULD BE USED ON STEEL STUDS BOTH SIDES WITH HARDLY ADDING WEIGHT GARDENER ALSO USE THIS FOR GREEN HOUSES

    Reply

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