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.

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