Undertile heating floor tile adhesive

[Mug-o-Latte]

Folks,

I recently laid some undertile heating on concrete, which I sealed with Ardex RS floor levelling compound (to protect it while tiling and also to give me a more level surface). I then tiled using normal flexible tile adhesive, but since then I have seen tile adhesive 'specially for undertile heating'.

Any thoughts on whether this is a sales gimmick, or am I likely to have issues when I turn on the undertile heating?

Cheers,
MOL.

 

[StickyP]

You should have no problems with a flexible adhesive in this case, provided that you have left room for expansion at the perimeters, in both the adhesive and the levelling compound. DO NOT grout the perimeter joints, use a deformable mastic (silicone, urethane) or leave open under the skirting boards.

Flexible (2-pack) or semi-flexible adhesive are suitable. Some manufacturers will add "suitable for under-floor heating" to clarify additional uses for their products

 

[Mug-o-Latte]

StickyP,

Cheers for the reply. Too late. Already grouted (with a flexible grout), and that included the gaps around the edge. The floor tiles butt up against the wall tiles.

So from what you are saying the floor will expand slightly when heated, so a flexible sealant at the edge will absorb the expansion. I'll just have to monitor it and if the tiles at the edge show signs of movement I'll dig out the grout and replace with flexible sealant.

Appreciate the feedback,
MOL.