I have two questions. (1) Do I need to tape the seems on the cement backer board or should I use caulking? (2) If the seems need to be taped, do I apply the Redgard before or after I tape the seems on the cement backer board?

I will be applying slate over the top of the board to create a waterfall.

Thanks

Gregg

You tape and mud over it. Let dry then apply redgard. Becarefull using that if there is an inspection. It won't be in the code book for a while and it may not pass. We've ran into it once before. We now use detra. But the redgard works well

Thanks for the help.

Schmidt