Hollow tiles with water underfloor heating

[Patricia Filipe]

We had a water underfloor heating installed and tiled over. 3 months later we noticed many tiles sound hollow. We worry this can signal future problems.

More details on our floor:

• water underfloor heating system fitted on XPS Overlay Lite Boards, laid on top of self-levelling
• porcelain tiles laid straight onto the underfloor heating boards (no screed, matt or board in between). builders claim the underfloor heating supplier said it was ok to instal the tiles directly on the pipes and the boards of the underfloor heating.

1) Is it normal for the tiles to sound hollow? Is it something related with this underfloor heating system?
2) Was the installation properly carried?
3) Will tiles crack / get loose in the future? And if yes can they damage the underfloor heating?
4) Is it worth replacing now or should we wait until we have problems to replace it?
5) Do we need to replace the underfloor heating and the tiles to sort this?

 

[demi34]

No no, sending some pics to how should be done

 

[davidjohnsir]

Sharing this query with fellow tiler. Maybe he knows

 

[shaney2000000]

Hi , Was the floor spread with a notched trowel to get a good even cover of adhesive of we blobs of adhesive used this would lead to the tiles sounding hollow

 

[Nick Curelaru]

Hi , Was the floor spread with a notched trowel to get a good even cover of adhesive of we blobs of adhesive used this would lead to the tiles sounding hollow

Normally the pipes should have been covered by a self leveling compound before tiling

 

[demi34]

Self levelling Bal Max first and then Rapid Set Flexible back butter the tiles

 

[Ajax123]

It will probably sound hollowness there is no mass beneath the tiles. Might be worth checking properly for delamination before rippin up as it may not be that

 

[Amethsyt]

It will probably sound hollowness there is no mass beneath the tiles. Might be worth checking properly for delamination before rippin up as it may not be that

Hi.
Sorry for hijacking this post.
I understand you have a lot of expertise in an area I require advice in(from reading your replies on other threads).
We have water based underfloor heating which was screeded over and then tiled.
We commissioned the underfloor heating but noticed two corner tiles (cut arround doorways) had developed hairline cracks.
Tiler says builder didn't screed correctly and builder is blaming the tiler.
Movement mat was used.
Have been using underfloor heating daily for past few months.
My question is, can we expect to see more cracks in the screed if it wasn't laid correctly or would it have been noticeable by now?
Many thanks