tub suround instal

bathtub wall surround install

I am installing a one piece tub surround over an existing tub. I have removed the old tile and and the damaged portion of the drywall to the studs. The existing drywall, that is not damaged is 3/8" thick. My question is, since I am installing a one peice tub surround, do you need to install the green water resistant drywall behind it? If so I may need to do more demolition, as the green drywall only seems to be manufactured in 1/2". Is there a sealer I can use instead of the green drywall? Thanks in advance for any advice!

any 3/8" drywall will do.

Thank you!

Some one-piece jobs don't need anything behind them, they attach to the studs. What does the manufacturer's instructions say? If they don't, it is best to ask them. The rigidity of the things varies a lot, and it may or may not need any support other than the studs.