Floor prep for whirlpool tub

[alwayssomething]

I'm installing a whirlpool tub in my bathroom. The instructions recommend, but don't require, putting in a cement or mortar foundation base for a solid, secure installation. My question is, will wonder board achieve the same effect or is it not strong enough? I'd hate to put the tub on wonder board only to have it crumble under the feet the first time we use it.

Thanks in advance!

[DUNBAR PLUMBER]

http://img.photobucket.com/albums/v70/DUNBAR/P1030020.jpg



I would use mortar.........solid as a rock when your done.