I was able to pick up the trailer for my tiny house on Tuesday, and made some (slow) progress last week. Modifications had to be made to the subfloor since the wheels were in a slightly different location than the plans called for. I ended up doing a lot of research on center of gravity, axle location and tongue weight.
To start the process, the trailer is jacked and leveled. Starting off level is very important! Then, half of the deck boards are removed. Removing the deck boards lightens the overall weight of the trailer, but still gives sufficient support to the subfloor framing.
Next, a layer of aluminum flashing is installed to protect the subfloor and insulation, as well as providing a barrier against critters.
The floor is framed with 2x4s on 16″ centers. The floor extends about 6″ past each side of the trailer to get the maximum living space possible. The floor framing is attached to the trailer by about 50 3-1/2″ lag screws screwed up through the bottom of the deck boards. Additional strapping will be provided later.
Finally, insulation board is cut and installed between the joists. I used 1″ thick Owens Corning Foamular 150 XPS Insulation since it is extremely resistant to moisture and has a higher R-value than other products. It’s insulation value is R-5 per inch, and I used three layers for a total R value of 15. It cuts very easily with a utility knife, and I was able to get an “almost” perfect fit. In addition, it is GreenGuard certified, so it has a low VOC content. I’ll still use some expanding foam in a few places to make the floor completely airtight.
First thing in the morning, I’ll install the plywood subfloor and begin building the walls and roof. Of course, that’s going to mean some additional planning as well since I don’t think I’m going with the original floor plan. So much for changing on the fly…