Emily Gonzalez

Thank you everyone for your replies!

In the article I posted, I think they mitigated some of the potential condensation/thermal bridging by applying the Rosoco waterproofing pitch to the underside of the marine grade plywood and taping all parts of contact with the trailer frame with the thermal tape. Then they place the joists over this, the insulation board, and tongue and groove pine.

My biggest concern is just the areas where the bolts go through the subfloor joists into the trailer cross members. As soon as the PNW freezing air hits the cross members, cold air is going to move through the joist wood to the warmer region, condensate and possibly start to mold. No matter how it's built, we couldn't avoid bolting down into the trailer frame itself. Is it possible to seal the top and bottom of the bolts somehow so that cold air couldn't move through as easily?

We are looking to design and build a mold-preventative tiny house on wheels roughly following some of the design/materials in laid out in this build:

https://www.mychemicalfreehouse.net/2020/12/passive-house-tiny-house-detailed-mould.html

We've been learning a lot about failed tiny house builds where thermal bridging isn't avoided and condensation builds around bolts and trailer studs inside of the house.

If we build a subfloor in this way on top of the trailer, wouldn't the steel bolts running through the 2x6 sub floor down to the trailer crossmembers still cause a good deal of thermal bridging? Any ideas on this or how to beat it?

Thanks!