We build tiny houses up to 12′ wide and 44′ long, up to a maximum of 400 sq ft. However, in all but three states of the US, the maximum trailer width is 8’6″ which is the standard Tiny SMART House width.
The total exterior height is just under 13’6″, which is also the legal height llimit for trailers, and safe for most bridges and overpasses on major roadways. We do not build taller than 13’6″ limit, though some people have required a slightly shorter build based on their own location and parking situation.
Choosing a wider trailer will require that you obtain a special wide-load permit and in some situations, one or two flag cars, to legally transport it down a roadway. Our standard Tiny SMART House width of 8’6″ does NOT require a trip permit on most major roadways. Check your state or local motor vehicle dept.
The walls are 8′ wide, plus with the siding, trim, trailer, and wheels, we’re right at the 8’6″ limit. Since tiny houses are generally only moved once or twice a year, sometimes even less frequently, many people find the simple and inexpensive permit worth it to have the extra interior space.
Check out our recent build, an Oregon Trail nicknamed “Oakland” that we built only 24′ long but 9.5′ wide. At under 250sq ft plus the loft, it was incredibly spacious design. When you’re living tiny, even only an extra twelve inches of width adds a significant amount of interior space.