I had always thought one of the advantages of PVCX over wood was the light weight. I have found a source and was going to order, but looking at the technical data, it seems that it is MUCH heavier than plywood??? This doesn't seem to make sense.

You can see the weights of plywood here:
http://parr.com/PDFs/PG_plywoodthickness.pdf

And here is technical data for the PVCX Komatex and Komacel:
http://www.kommerlingusa.com/komatex/technical.cfml
http://www.kommerlingusa.com/komacel/technical.cfml

As you can see, a 4X8 foot sheet of 3/4" thick plywood is about 60.8 pounds

However, the same size and thickness of PVCX are 94 pounds and 76 pounds per 4X8 sheet for the two brands respectively? Same pattern for the other thicknesses.

I wanted something light weight, now I am quite confused. Does anyone know?