I am building a house and it is to have a large walk in shower. The builder is recommending putting plywood on the shower walls instead of cement backer board.
The shower is to be tiled from floor to ceiling.
What do you recommend?
Thanks Phil

Cement board should be used for the shower, plywood is not good for wet areas.

Fire the builder. Duaroc, Hardibacker, Wonderboard, or pay me to fix it in 5 years.

Harold and Amricca are right, this guy has no clue. Just think of what else he is doing that did not come to your attention. No builder should ever think plywood would be appropriate in a shower. I still run into some who try to use greenboard or paperless drywall, both wrong for a shower stall. I use 1/2" Hardibacker board glued and screwed, tape the seams with fiberglass tape and the same stuff used for the tile, modified thinset. James Hardie Backerboard (http://www.jameshardie.com/homeowner/backerboard.shtml)