moving tiles...help

[oursam78]

Hi
We moved into a 1930's house with underfloor heating (wired matting) and ceramic tiles in the kitchen. The kitchen had been extended so half the floor was concrete and half tongue and groove floor boards.
The concrete side of the kitchen is posing no problems what so ever, yet the grout in the wooden side is cracking and there is some movement in a few of the tiles. I don't think it is deflection but more the boards expanding and contracting underneath.
This is starting to look a mess and two of the tiles have cracked over the last couple of days. we think we can get the same tiles and if so are considering lifting the tiles on the timber side and replacing them ?
I have read on here about using plywood on top of the floor boards but we are governed by the height of the concrete floor. We could probably get away with 6mm max.
Does anybody have any suggestions on how we can salvage our floor ?

Any advice appreciated

 

[Ian]

A 6mm cement board would be the best option to overboard the floor boards, so long as you are sure the floor is 100% deflection free. Another option is to replace the floor boards with 18mm ply and overboard that with cement board, adding extra noggins to the joists whilst the floor boards are up. Welcome along to TF.

 

[White Room]

Hi and welcome...what tiles are they.

 

[kilty55]

hi,so at present half your floor is tiled direct onto the floorboards?

 

[kilty55]

is ufh laid across the boards as well? and also under the tiles on concrete side?

 

[Stef]

Jamie thats the way im reading it,

Theres not an easy fix here, that whole floor, (all the tiles) need lifted & re-done.

 

[oursam78]

Yes ufh laid across both to heating the entire room

 

[oursam78]

Yes that is correct

 

[Sean Kelly]

If the under floor heating is also on the floorboard side then lifting all the tiles on the floorboard side will stretch the wire and your UFH will not work. What tile pattern do you have? Is there a grout line that runs down the middle of where the concrete meets the floorboards? Will it bother you that you will have 2 different floor levels in your kitchen (if you just replace the floorboard side). As Robson said, all the tiles must be lifted and all the floor made the same level. Do you know how long ago this work was carried out?

 

[kilty55]

same advice as robson for me..lift the lot..i cant see how your going to manage to lift half a floor and save the ufh then lift it and re board to same height as the concrete floor with that in place its just not going to happen

also i would use a membrane on that floor as there are 2 diff substrates there also

 

[Sean Kelly]

Just read your last post. Is the UFH on 1 or 2 circuits? What size area are we talking about?

 

[oursam78]

Ok so if we were to lift the entire floor and replace the ufh what would be the best options for boarding out ?

 

[oursam78]

We wouldn't want to replace the boards though as suggested due to the kitchen already fitted

 

[oursam78]

Sean its 1 circuit and approx 8 sq meters.

 

[oursam78]

Kilty55 I hear what you are saying but Couldnt the ufh on the timber side not be cut and replaced and then reconnected to the wire on the concrete side ?