Originally Posted by charles_m
Would applying a urethane or varnish seal in the chemicals used in the glues in osb?
Yes and no.
Yes encapsulating the wood will work to seal it from the moisture outside and seal the chemicals inside. This is how some boats are built. With wood and fiberglass / epoxy.
No, because the glue is not nearly as good as marine grade plywood. One breech of the encapsulation, or hole in the coating, and it would start to swell like a sponge. This will be fine for a living room, but no good for a bathroom where humidity levels are way above 19% far to frequently.
One more example I like to use it baseboard trim. Here we can get hardwood, finger joint pine, and press wood.
Hardwood is best for high humidity if not using plastic trims,
next would be the finger joint pine if properly sealed with paint.
Not any good is the press wood, First little nick out of the paint and it sucks up moisture like a sponge. After swelling it completely looses it's seal, taking one more moisture till it looks like a bloated mess.
Originally Posted by Zephod_beeblebrox2
How do you insulate with bare metal?
You laminate or glue the rigid Styrofoam right to it. Finish wall covering glues on the opposite side of the rigid Styrofoam. This is how the high end insulated warehouses here in the Canada are built. Remember we live in a age of adhesives.
Or you encapsulate the 1.5 inch by 3.5 inch wood strapping in the Styrofoam so no bug, moisture, ect can get at it. This is what I'm doing on my bus build.