Redgard mortar shower pan that already has rubber liner?

[lacrebob]

I've built a shower pan with a mortar base (sloped), rubber liner, and mortar base on top of the rubber liner.

I'll be using redguard as my waterproof membrane for the Hardibacker walls and shampoo alcoves.

This shower will have ceramic tile on the walls and porcelain tile on the floor.

Is there any harm in using Redguard for this shower pan since the pan already has the waterproof membrane? Would water get trapped? Does application of Redguard lessen the bond between porcelain tile and the mortar pan?

[TileArt1]

Hey lacrebob,

No need to use redgard on the floor. It may not create a true "moisture sandwich, but it certainly won't help anything. It may not allow the weep holes to work as effectively, I don't know. I would just use the redgard on the walls down to the floor.

[lacrebob]

That works for me.