Ditra concrete floorboards

[Sean Kelly]

Kitchen is currently floorboards and dining room is concrete. Both areas are level.
Customer wants 1200x400 wood effect porcs to cover both areas (approx. 15sqm).

I have not seen the job, but if the boards are sound and have no deflection, then could the whole area be Ditra’d (new word).

Customer also wants UFH. Would I just attach the cable to the Ditra then just cover with SLC? (this would save me from filling the square indents with addy). Thanks.

 

[cam_low]

why not use ditra heat-e ?

 

[White Room]

I'd want to do an expansion joint between the two surfaces....

 

[m3fitter]

I'd want to do an expansion joint between the two surfaces....

wouldn't decoupling it be fit for this purpose, as there would be different expansion / contraction rates on these different substrates ?

 

[White Room]

I know where your coming from but if there was any deflection in the timber floor it's not something ditra copes with, for that reason an expansion joint would be my preference

 

[Sean Kelly]

The problem is the tiles will be brickbond spanning the concrete/wood.

I saw a demo of the Ditra Heat at CTD last month. I've just googled the price of the 8mtr kit at £506. I want 15sqm so I guess that will be another £100 for the extra mat. Normal Ditra and a heating kit from the Underfloor heating company would be less than half the price. I know it's not my money, but I do know the customer will not spend that amount.

 

[Qwerty]

I enquired about this same scenario last year. From recollection Schlüter don't advise SLC over ditra to fill the voids and will void any warranty. I don't see any real issues personally but put in a call to the tech team mate to get the word from the horses mouth.

 

[Sean Kelly]

There was a rep from Ardex at CTD too. He said he would glue Ditra down with Ardex AF200 then SLC over it. I've just looked at the Ditra Handbook and it has the UFH under the mat!!! Got to do some more investigation, as the words modified and unmodified thinset started appearing on my google searches!

 

[m3fitter]

AS far as i'm aware, Ardex are the only manufacturer to guarantee the use of Ditra with Anhydrate and UFH, and adhering porcelain, ie: Ardex, Ditra, Ardex, porc's, apparently, too much polymer in others, I checked with mapei and bal helpdesks

 

[Sean SML Tiling]

Standard ufh is cheaper but by the time you pay for slc and labour to slc the floor it wouldn't be much difference in price.

 

[Dougs Third Go]

There was a rep from Ardex at CTD too. He said he would glue Ditra down with Ardex AF200 then SLC over it. I've just looked at the Ditra Handbook and it has the UFH under the mat!!! Got to do some more investigation, as the words modified and unmodified thinset started appearing on my google searches!

that's where it should be Sean

 

[White Room]

I enquired about this same scenario last year. From recollection Schlüter don't advise SLC over ditra to fill the voids and will void any warranty. I don't see any real issues personally but put in a call to the tech team mate to get the word from the horses mouth.

I was told it can be done when I was at Schluter but the preference is underneath for the ufh.

 

[Qwerty]

Thanks Mark

 

[Sean Kelly]

So my options are:
Overboard the whole floor (only 15sqm) with 18 ply. Then UFH / SLC / Tile
Overboard the whole floor with 6mm Hardibacker. Then UFH /SLC /Tile
use Ditra Heat E straight onto the existing floor. Then tile.

I have never used Ditra and UFH together. Was surprised to see that the UFH goes under the Ditra. So that means UFH / SLC and then Ditra.

 

[Qwerty]