I have worked for a tiling company that installed UFH, the Warmup type, over Ditra matting. However, there seem to be views that doing so is not a good idea....the theory is that the wire heats up and melts the Ditra??.........could anyone enlighten me on this?

ufh doesent go on top of ditra,

ufh then slc then ditra

And no it wont melt it.

thanks for your reply.........another question.....if there is no risk of melting the Ditra, then what would be wrong with installing the UFH on top of the Ditra?

the ditra is a decoupler between substrate and tile.

forgive me, but I don't understand..........the felt-like layer on the underside of the matting is the decoupling membrane.........the top side, by virtue of its design, allows the tile to lock into the matting as the addy shapes to the recesses of the matting.....there surely isn't any decoupling action between the topside of the matting and the tile ??

Originally Posted by Brad

forgive me, but I don't understand..........the felt-like layer on the underside of the matting is the decoupling membrane.........the top side, by virtue of its design, allows the tile to lock into the matting as the addy shapes to the recesses of the matting.....there surely isn't any decoupling action between the topside of the matting and the tile ??

Your right, but if you introduce the heat mat on top of the Ditra, your creating an area of greater lateral stress rendering the Ditra less effective. If the heat mat is under the Ditra, then you allow the product to do it's job properly allowing the tile to heat up at a different rate to the substrate.

Page 12
http://www.schluter.com/media/DitraHandbook.pdf

thanks for that...makes sense

thanks for the link mate..........didn't come across it when on their website earlier.....good diagrams...worth bookmarking...top man!

Originally Posted by Brad

thanks for the link mate..........didn't come across it when on their website earlier.....good diagrams...worth bookmarking...top man!

No problem !