please confirm order of floor install i am using is enough/correct spec.

[Jas007]

Tiler has spec'ed 1) 10mm Cement Tile Backer Insulation Boards - 2) UFH Mat with Latex - 3) Adhesive - 4) Ditra Mat - 5) Adhesive - 6) 12mm (600 x 400mm) Marble tiles.
I am tiling through and one room is concrete subfloor (newly laid using steel mesh and kingspan below and sides for expansion).

I am NOT using an expansion joint where concrete subfloor meets wooden subfloor as wood floor according to tiler is solid enough and using above spec.

existing wooden subfloor is 400 mm between joists (2" X 8") with 18mm chipboard.

Would do you guys agree with my tiler?

Thanks and regards

 

[Ajax123]

Nope. Should be expansion/movement joint where different substrates meet. If not it is likely to lead to a crack.

 

[nybor62]

agree with ajax
the ditra will help with any lateral movement , but any vertical movement were the 2 substrates meet will be the problem
do a Silicon joint rather than a mechanical joint

mapei and weber do matching Silicon for there grouts and if done right you will
notice it

 

[Jas007]

many thanks for advice... My kitchen and diner were separate rooms and I knocked the parting wall through - they are concrete and wood substrates respectively. I levelled the concrete floor with wood subfloor using some latex then tiled both rooms through with ceramic tiles 16" X 16" using tile adhesive. Did NOT use tile backer boards, no ditra and no expansion joints. The ceramic tiles and grout has been fine for two years used by a family of five including teenagers.

So my question is what different is that from my Hall (wooden subfloor) and garage conversion (concrete subfloor)? In fact would you agree it will be "safer" than kitchen / diner? As will be using ditra, 10mm cement backer boards and flexible adhesives.

 

[Dan]

You wont get a tiler on here to tell you not to use an expansion joint where two different substrates meet. Especially two different ones with so much difference in expansion/retraction rates and deflection rates.

If you don't want to physically see a movement joint then make sure a 'grout' line falls right where you need it, and then Silicon the grout joint using the same colour Silicon as the grout. You'll hardly tell its there unless you study it. Mapei grouts match their silicones (or the other way around) perfectly.

You've been lucky with your existing situation. Using flexible levelling compound throughout would have helped with that (if I'm reading that right) but it isn't fail-free yet it's only been down a couple of years and only seen hot/cold times of the year twice. Give it another few years and you probably will see some damage occurring - at a guess.

 

[AliGage]

You wont get a tiler on here to tell you not to use an expansion joint where two different substrates meet. Especially two different ones with so much difference in expansion/retraction rates and deflection rates.

If you don't want to physically see a movement joint then make sure a 'grout' line falls right where you need it, and then Silicon the grout joint using the same colour Silicon as the grout. You'll hardly tell its there unless you study it. Mapei grouts match their silicones (or the other way around) perfectly.

You've been lucky with your existing situation. Using flexible levelling compound throughout would have helped with that (if I'm reading that right) but it isn't fail-free yet it's only been down a couple of years and only seen hot/cold times of the year twice. Give it another few years and you probably will see some damage occurring - at a guess.

Spot on.

I don't understand what the problem is. It's not hard to do, it's not complicated. But it does give you piece of mind when the it's all said an done.

 

[Jas007]

Ok - so what you guys are saying I can continue my tile brick block pattern into garage from side of hallway. Without a pattern break but with a grout - Silicon line exactly where the joint meets? And it won't be to noticable?