How can I seal regular drywall in a tub surround before putting on plastic liner?

Question

I bough 4X8 sheets of Plastex, I don't want to redo the drywall, ugh, can I put something on it to waterproof it before glueing on the Plastex?

It's sort of sem-thick but floppy white plastic sheets.

How best to cut this stuff?

I bought liquid nails tub surround glue, to I trowel that on?

Thank-you

Answer 1

You really need green board and it would probably be cheaper to replace the drywall than to use KIELTS sealant.

Answer 2

FRP is the way to go here if you merely just want to provide an inexpensive durable white or grey plastic shower liner.  Do not use Liquid Nails.  Buy a cheap "V" Notched  trowel and use latex FRP Adhesive or similar vinyl/plastic adhesive available in the home centers.  Stay away from the cans of Liquid Nails FRP Adhesive. . . it's a mess and miserable to clean up.