One of the cool things about building a tiny house is that there is no one way to do it. If it’s on wheels each trailer is different and each person’s design is a little different. Sometimes there are lessons you can learn from people who have come before you and sometimes you just have to wing it. When building on wheels there are a couple of pretty common constraints though. You don’t want to go wider than 8.5 feet because doing so requires a wide load permit to move it. Additionally, you don’t want to go taller than 13.5 feet. Unless of course you don’t mind having the top of your house ripped off when you go under bridges. There are bridges that are lower than this, but it’s generally the standard height. Special GPS units, such as those for RVs, are a good thing to use when moving.
I did run into a little bit of an unexpected dilemma with our trailer though. The manufacturer had welded rings to secure the wiring. This makes perfect sense for a standard trailer, but the rings got in the way of how I planned to do my flooring. I had to pry the rings off and disconnect the wires to get them out of my way. Ultimately I will notch the joists and secure them in it. It wasn’t too difficult, but it was a step that I hadn’t anticipated.
I got on a little bit of a rant there, but what I really wanted to share with you is that we got a start on our tiny house this weekend. We picked up a utility tarp, some bungee cords, and some lumber to get started. I spent the majority of the last week thinking through how I wanted to attach the floor joists. Generally people would just build their floor above the trailer which results in ~4 inches of lost height. Since I’m a little on the tall side I really didn’t want to do that. Alternatively you’ll see some people build directly on the trailer and generally struggle with getting much insulation in the floors or struggle with “thermal bridging.”
We went with a method that was loosely inspired by a fellow that goes by the name of Moose. With this method we are able to get 6 inches of insulation in the floor without sacrificing precious inches of headroom. I essentially ripped 2x6s to about 4.5 inches. These then attach directly to the steel frame. From there I lay a 2×4 sideways and it rests on top of the steel beams and the ripped 2x6s. Doing this gives me a little additional support, but largely places the load on the steel beams rather than the wood framing. The benefit of this method is that I have a platform to easily screw into for my subfloor as well as flashing that will go under the trailer. I don’t completely get away from attaching wood to steel, but I am able to minimize it.
I got everything cut and dry fitted into place today. The next task will be drilling holes through the steel beams to connect the joists. This gives you a pretty good idea of how it will look when it’s finished though.
This shows you one method for creating a joist system for your subfloor. Still work to do, but I’m happy to see progress and think we’ve come up with a pretty good solution.