In The Small House Book by Jay Shafer of Tumbleweed Houses, he says to put metal flashing under the subfloor. In then in a recent video of building a tiny house, they don’t do it. They build directly on the deck of the trailer.
The stated purpose of the metal flashing was to keep water and bugs out from under the house. Given how tedious it was to install, next time I’ll probably leave the decking and cover it with roofing felt to repel water and keep out bugs. Surely it will do an adequate job.
This is the trailer after I started removing the extra decking:
Here’s the trailer after all the extra decking was removed and I built it up 2″ to make it flush with the metal frame of the trailer:
I put the trailer up on jack stands so it would be level and not wobble while I work on it:
Then I started the framing on top of the trailer:
I installed the metal flashing on the upside down framing:
Then I turned it right side up. If you notice, I ended up with some bowing of the metal in the middle section:
I fixed that by drilling screws into it from underneath. The trailer has metal braces right across where I would have put the screws in so I had to add blocking:
And that pretty much fixed it:
Although it was probably overkill at this point, I went ahead and added 12 hurricane clips to make sure this foundation isn’t going anywhere without the trailer:
Then I cut and added the R-19 insulation. Turns out that according to the structural standards I read about in Building An Affordable House, 24″ between studs is just fine even though most people still use 16″.
The only issue I’ve found with that is that they manufacture insulation for 2″x4″s in 16″ widths instead of 24″. The 24″ wide insulation is made to fix between 2″x6″s. So there is a little compression of the insulation. I googled the issue and all I found is that it might not work quite as well.
So maybe it’s a R-17 or R-18 now. Seeing as standard 2″x4″ insulation is R-13, I’m happy with that:
Here’s me measuring and cutting the OSB subfloor:
And here’s placement of the last piece:
On to the walls…