floor tiling on timber and screed

[MDD]

I am new to the forum so please forgive me if I don't get it right. We are carrying out work on a property and have a situation where the floor to be tiled is half screed and half timber. The client wants underfloor heating (electric). My concern is that the timber floor will move and the screed floor will not move so where they join will give rise to an obvious problem. Any help is appreciated.

[Ajax123]

Movement joint between the two substrates is essential

[MDD]

Thank you for replying can you please tell me. Would the movement joint be something like the Schluter Dilex movement joint and if so would that be all that was needed.

[Ajax123]

That would be the sort of thing yes. There are some pretty good ones available so you should be able to choose one that allows you to make it a feature rather than an eyesore.

[whitebeam]

I'm no expert on ufh but you may need 2 seperate supplys for each part of the floor

[Ajax123]

I can't answer that either but if it is the case then it makes a movement joint even more essential cos you would split the floor into two separate zones.

[peckers]

You may want to use an insulation board on the screeded floor to stop the heat escaping threw the floor if you do this then you would want to do the same to the wooden floor so as to keep the floors the same level, you will need to create an expansion joint between the wood and the screed floors and this must carry on threw the insulation boards and also threw the tiles. then as said before use two seperate heating mats/cables as you will have two zones.

[doug boardley]

as above ^^^^ from me

[deanotile]

as above for me also

[MDD]

Hi again Thank You All for replying. To try and understand from my point of view as to what is being said.
1. An expansion joint needs to be installed along the line of the join between the timber floor and screed.
2. Insulation boards laid beneath the underfloor matting covering the whole floor with the expansion joint seperating the two floors.

If that is what is being said perhaps someone might confirm.
Would an uncoupling membrane such as Ditra be of any use??

Any help is appreciated

[peckers]

Hi again Thank You All for replying. To try and understand from my point of view as to what is being said.
1. An expansion joint needs to be installed along the line of the join between the timber floor and screed.
2. Insulation boards laid beneath the underfloor matting covering the whole floor with the expansion joint seperating the two floors.

If that is what is being said perhaps someone might confirm.
Would an uncoupling membrane such as Ditra be of any use??

Any help is appreciated

That's what I would do as to the decoupler mat what tiles are you using?

[Dave]

Is the join between the 2 floors a straight one.?

[MDD]

Thank You, Yes the join is a straight join and I have to find out what tiles are being used

[Dave]

Then Yes! use a movement joint.. this could be a pre-formed joint or a cold joint..

[MDD]

Thank You, appreciated.