XPS tile backer boards on blocks

[john2k]

Just an update on this. I’m a few days away from having to put the XPS qBoards on the blocks. I emailed QBoard tech support about their advice and they advised to just dot and dab it with tile adhesive. So I’m thinking as long as I don’t leave big gaps between the dot and dab maybe since I have foam adhesive available too I could do dot and dab and just apply small a amounts or foam adhesive just as extra belts and braces. They said to then fix it mechanically after the tile adhesive has dried.

Question: should I apply sbr or anything to do grey blocks before hand?

 

[noseall]

Just an update on this. I’m a few days away from having to put the XPS qBoards on the blocks. I emailed QBoard tech support about their advice and they advised to just dot and dab it with tile adhesive. So I’m thinking as long as I don’t leave big gaps between the dot and dab maybe since I have foam adhesive available too I could do dot and dab and just apply small a amounts or foam adhesive just as extra belts and braces. They said to then fix it mechanically after the tile adhesive has dried.

If you use wet adhesive/foam adhesive combo, the foam has the potential to lift the board off its dabs.

You are over thinking it really as the dabs just become spacers once the mechanical fixings are screwed through. Just use dab - true up the board - wait for it to set - fix through the board and dabs.