Undertile heating under 18mm marine ply, with travertine tiles

[DavieA]

Hi advice needed before attempting floor. Wet Ufh being installed and current chipboard being cut out in places to allow pipe to be layed. Pipes will be inbetween joists therefore no room for noggings to be inserted, so to ensur strong deflection free floor and am not wanting to take risks. I plan to relay chipborad thats been removed and screw to joists as its T&G, then lay 18mm wbp ply with 2mm expansion gaps between boards and on top lay dural ci+ decoupler membrane. Fix mat and tile using Spf.

I realise it wont be the most efficiant ufh system but heat will still get trough it, I just think its prob the safest way to ensure stong stable floor for soft travertine tile.

All comments/advice will be greatly recieve.Thanks again guys.

 

[Gazzer]

Not very good with heat needing to get through 36mm of wood and then Dural Ci inc adhesive !

What is beneath the pipe work ?

 

[DavieA]

Some sort of Insolation board that pipes and clipped into then are set in a screed.

 

[Gazzer]

Its not ideal but the ply will add strength but only you will know if its enough strength when you walk on the floor and feel for deflection.

 

[DavieA]

Yeah its like you said defo not my first choice or ideal. The floor flles solid just chipboard but with the chipboard being cut for piping I think the safest plan would be to add correct thickness and type of ply along with a decoupler to ensure the risk of travertine cracking etc is mimimised but is there are other ways im not aware of im open to suggestions.

Not done alot of Travertine work so want to cover all the bases, just wondering if the steps listed appropriate for the conditions.

 

[Peter]

Not feasible to lift the chip board, replace with 22mm ply and tile with a two part flexi?

 

[DavieA]

Thought about that and suggested it but joiner wasnt happy laying ply onto joists without additional noggins, which he cant do due to the ufh pipe and screed etc. Therefore I thought 22mm chipboard with 18mm ply overboard to ensure floor is solid after all chipboard will have been cut in sections for ufh install then membrane to allow lateral movement and expansion. Finally tile using keraflex SPF.

100% dont want any issues with floor it be a nightmare.