Under carriages

Okay.
For the bottom panel of your TD, the one that faces the ground and sits on top of frame, I have several questions:
1. Has anyone used exterior grade paneling for that exposed piece?
2. In coating the underside, have you also coated the end grains with the same coating, or used something different for aesthetic purposes?
3. How does the coating hold up with the exterior grade (usually pre-treated) plywood?
4. I have to biscuit join three pieces of paneling to get to my 5x10 floor measurement. How well does exterior grade paneling work with this type of joinery?
5. I am thinking of going with regular plywood (since exterior grade is usually warped). Coating just the one side with roof tar, and the edges with an epoxy or varnish to seal them.
Thoughts?
For the bottom panel of your TD, the one that faces the ground and sits on top of frame, I have several questions:
1. Has anyone used exterior grade paneling for that exposed piece?
2. In coating the underside, have you also coated the end grains with the same coating, or used something different for aesthetic purposes?
3. How does the coating hold up with the exterior grade (usually pre-treated) plywood?
4. I have to biscuit join three pieces of paneling to get to my 5x10 floor measurement. How well does exterior grade paneling work with this type of joinery?
5. I am thinking of going with regular plywood (since exterior grade is usually warped). Coating just the one side with roof tar, and the edges with an epoxy or varnish to seal them.
Thoughts?