Re: I-28 Vinyl Headliner Replacement
I'm not sure we are talking about the same material. Did you check the link I posted?
The material I'm referring to is .09(3/32) inches thick, Fiberglass Reinforced Plastic, it's all synthetic, lite, high strength, and resist mold and mildew, used in restraints, airplanes, etc. It's similar to the opaque textured plastic used for the light fixtures areas on a lowered ceiling, or office lights, but is more ridged.
I have a friend who did his headliner in a Colombia with the material I'm referring too, and it looks great.
Did you use MDF (Medium Density Fiberboard)? MDF would absorb water, be thicker, heavier, and deform over time if suspended overhead.
I would think you would have had the same condensation issue with the vinyl headliner since it does not breath either. The foam between the fiberglass and vinyl would soak up the water.
If you put a cloth headliner instead of vinyl, it would breath better, or use the vinyl headliner material with the small holes, like used in cars.
I would try insulating the fiberglass with Styrofoam, or spray on closed cell polyurethane foam, then installing whatever option you choose for the headliner.
I should be taking on this project this summer, and will post up my process and pictures, when I'm done.