A frame becomes a floor

Completing for floor box in my tiny house

Like many tiny housers, we built the floor box in 3 sections and each section was covered on the bottom with overlapped aluminum flashing backed by 1/4 inch plywood to keep out any pests or moisture that might want to creep in from underneath. 

To accomplish this, we first flipped over each piece of framing, nailed/tacked/screwed on the plywood and flashing, and then had to flip each piece back over (ai yai yai!) and push and pull everything to be perfectly square (or as close as we could get it) and screw the sections together and screw it all to the trailer. (In case you're wondering, yes, a metal drill bit going through the metal trailer does make a horrible sound.)  Then we  filled the edges of the frame with a spray insulation and filled the cavities between the 2x6s with some lovely wool insulation, and then covered the top with 1/2 inch plywood, including the little bump out over the trailer tongue. 
And, of course, after it was nearly done I recalled my earlier concerns about offgassing formaldehyde in the glues used to make plywood and decided to seal it with Safecoat's HardSeal. 
But it's all done now so (ta da!) say hello to my brand new tiny home floor box!

Aluminum flashing on the bedroom section,

The bedroom section has been flipped over and we are beginning work on the entry section.

Shimming and shifting--trying to get the floor perfectly square.

When all else fails, use a clamp--a really BIG clamp!

Sealing the outer edges against bugs and drafts.

Insulation in the floor.

The blocked off areas are where plumbing will have to go through the floor.

The sub floor, fully boxed in and sealed.

This may be the last time a cartwheel fits inside my tiny home!

Making the tiny house floor box.