[Huskyfan68]

I want to remove the old 1970 tile around the full size tub- Once I do that I wanted to put up the 3 piece "surround" instead of re-tiling. Are these meant to go right over the studs or do I need to put waterproof sheetrock first?

 

[WhatRnsdownhill]

depends on what type you get, they can be both ways..

 

[joecaption]

The best ones are attached directly to the studs, there at least 3 times as thick.
Pay attention to the install directions, often a few studs will need to be added to have something to attach it to.
Always best while that walls opened up to add 2, 2 X 6's laying flat in the wall where a door or curtain will be attached, and in the back wall where grab bars will be installed.
Sterling makes some good ones.
http://www.homedepot.com/s/bathtub+enclosure?NCNI-5