ditra mat or not?

[wdk]

Hi, wondered if you good folks could advise on whether ditra mat is advisable/essential for my upcoming tiling. I've self built and extension approx 50m2 which will be a kitchen/diner (with 2.5x1.5m roof lantern) a utility room and a wet room. Laid ufh over kingspan and screed Larfarge Gyvlon to approx 60mm (2 weeks ago), expansion gap on every wall. I was intending to cure the screed and commission the ufh in a month or so - test with hygrometer, clean and seal the floor and then tile (uncalibrated slate). I've read that a lot of people use ditra, are there any significant benefits to using it? I've just been reading a thread where it seems the matting has parted company from the screed so I'm wondering if it will cause more problems than it solves. I'm not hugely experienced in the tiling department - any advice gratefully received.
Will

 

[Urban Essence]

Hi Will

Ditra Matting is usually used on plywood floors to absorb any movement before it reaches the tile and cracks the grout lines, or the tile.

If you are tiling onto screed there should be no need to use ditra matting

Rob

 

[Gazzer]

Hi Will

Ditra Matting is usually used on plywood floors to absorb any movement before it reaches the tile and cracks the grout lines, or the tile.

If you are tiling onto screed there should be no need to use ditra matting

Rob

Interesting, what happens when the underfloor heating is turned on and using a natural stone too....rather you than me.

 

[wdk]

thanks Rob, I ask as my tile supplier implied it dispurses and moisture left in the screed (how it would do this over 50m I'm not sure) whereas a lot of guys here say they always use it over ufh - to help with any movement I presume

 

[grumpygrouter]

Hi Will

Ditra Matting is usually used on plywood floors to absorb any movement before it reaches the tile and cracks the grout lines, or the tile.

If you are tiling onto screed there should be no need to use ditra matting

Rob

Really? Ditra has many more uses than that and i assume you are talking lateral movement of the ply and not vertical? If I was laying limestome, marble or other soft materials I would tend to recommend Ditra, screed or not!

 

[Stewart]

I would always use a de-coupler when using natural atone and underfloor heating.

 

[doug boardley]

same as Stewart for me

 

[Ken Bruty]

I wouldn't fix a natural stone directly to a ufh screeded floor, I've had to sort out so many problems with installations fitted this way, either grout cracking, filler popping out and worse - tiles completely split in half. I would always fix onto ditra matting where ufh is involved.

 

[Pebbs]

Will,

Youve gone all this way and spent money out, if you want peace of mind, do yourself a favour and get that ditra down. For me its not even an option not to put it down, belt and braces.

Pebbs

 

[Diggy]

Agree with all the others , Ditra is a must with stone on UFH , especially if the UFH hasn't been commisioned prior to tiling ( which it ought to be really ) . However , UFH is rarely commissioned b4 I get there usually , so Ditra is a given to negate the majority of the risk.

Got to start a limestone floor on Monday - 150m² - seeing Ditra in my sleep :0) . 4 tile pattern , biggest is about 900 x 600 . Thinking of hiring a crane to lift the big ones into place , me old back not up to it these days. :0)

Cheers

Diggy