Designing Kitchens and Bathrooms - installing backerboard

Hello.

I do have a question concerning where to place the backerboard... According to the books I checked, the backerboard goes IN FRONT of the flange of the bath tub with a space of 1/4" between the rim and the board which will be sealed with silicone. Behind the backerboard furring strips fill the gap between the stud and the backerboard to keep the wall level. This is the way I have done it. Meanwhile I hired a contractor to build a deck behind our house. He saw what I was doing in the bathroom and told me that I should never trust the books! According to him the backerboard goes ON TOP of the flange, otherwise the backerboard will get wet (??). Of course this is the way to avoid having to use furring strips, however to me it seems that putting the backerboard before the flange is an extra assurance to avoid leakage...... Any opinion on this I would appreciate...

thx, Gwendolyn

If this backerboard has a masonite material embedded in it, this product has a poor reputation when subjected to consistent moisture.


I would suggest a fiberglass unit or wall set up.


As far as the design of flange on showers or tubs, it is meant to go over top flange, with a seal of silicone whether it be greenboard or tile or whatever is used. This insures that water cannot get behind tub, but that does not mean if you use the wrong material, such as masonite board, it will prevent damage.


Masonite will draw water into it and start to rot almost instantly if silicone beads break down, which happen very easily.

This is wonderboard, cement backerboard, meant to be used for bathrooms....

ahhhhh good then..........you should have no problems then.......

thx,:)

The backerboard is going to get wet. the idea is to provide a path that will be inside the tub, and minimize contact with adjoining wood that could also absorb moisture. While tile itself can be reaonably waterproof, grout is a cement material and wicks moisture. The backerboard also wicks. You did the job correctly by shimming it out. The truly paranoid shim it with plastic or place another barrier between the board and the studs. Nothing still beats a full up mud job...

thx, I appreciate your input. At least I know now that I am not doing such a bad job :)

thx, I appreciate your input. At least I know now that I am not doing such a bad job :)