Hi guys,
My trade is a qualified plumber/heating engineer for the last 25 years. I often take on the tiling of my bathrooms where the customer does not want anyone else involved. Over the years I have fitted lots of ceramics, porcelain and recently stone. i have always taken the advise of the suppplier with the use of adhesives, primers grouts and the like.

i have recently taken on 160m2 of trav in three bathrooms, where someone else started and was really out of his depth, lippage on every tile - no way - he got thrown off the job by the customer. i am left with floors - detra Mat - tile safe membrane (wet rooms floor) - electric matt. my question is what should my floor build up be Detra Matt / Electric matt with latex / membrane or Dertra Matt / membrane / Electric matt with latex.

i would be grateful for any suggestions.

Andy.

Where were you when I needed you de la mace...no heating for 5 days now...I was begining to resemble eskimo nell!

Andy are you saying he left the ditra on the top? because he should have done its the last thing to go down. If your levels are right then you can go ditra on top of the heating mats, if your not so sure then level it and then put the ditra on top of that.

What is the substrate? dont tell me wooden floor boards, or I may just combust.

Pebbs

Subfloor has the heating mats installed,
level out the floor with either self leveler or thin-set (flexible),
install ditra mat
install tile

Andy.
You can lay the Ditra matting above or below the UFH -according to Ditra - but it is more effective above and has better decoupling properties. Would suggest it would also provide a better waterproofing aspect.
With Tilesafe membrane you must check the wattage of the mat - I believe they only recommend 100w/metre output.

Have fun.

A very interesting question, as above Ditra, Dural etc. say de-coupler can be laid above or below ufh. Yet Dural have informed me recently that a 4mm trowel is ideal to bed the fleece into ( which I did know ) for the CI membrane to work most efficiently . My only concern is if you lay the ufh mat, on average 3mm. Then use a 4mm trowel to bed the CI mat, you will not achieve full coverage to the fleece.

The last job I did using Ditra over the ufh mat I used a 10mm half moon trowel, I am sure I achieved 100% coverage. 4mm is fine if you are laying Ditra onto flat substrate, and then using ufh over the top. But if you need to lay Ditra over ufh you will need a deeper notch trowel imo. Hope this makes sense.

Originally Posted by Phil Hobson

A very interesting question, as above Ditra, Dural etc. say de-coupler can be laid above or below ufh. Yet Dural have informed me recently that a 4mm trowel is ideal to bed the fleece into ( which I did know ) for the CI membrane to work most efficiently . My only concern is if you lay the ufh mat, on average 3mm. Then use a 4mm trowel to bed the CI mat, you will not achieve full coverage to the fleece.

The last job I did using Ditra over the ufh mat I used a 10mm half moon trowel, I am sure I achieved 100% coverage. 4mm is fine if you are laying Ditra onto flat substrate, and then using ufh over the top. But if you need to lay Ditra over ufh you will need a deeper notch trowel imo. Hope this makes sense.

But wouldnt you SLC 1st ?

Or you can Latex Slc over the ufh before installing Ditra etc on 4mm bed..

In a big area if you have the time yes, in a small area not always poss due to not having the time to allow slc to go off

Just to clarify my previous post, on a large area I would always slc over ufh, the last job I did using this method was only 5m2 I did not have the time to slc over heating mat. It would have put another day on the job, sorry if I did not make myself clear, I guess I was thinking out-loud

this is how I do it, if you see where there is no de-coupler there is signs of the heat mat under the latex levelling.

oh, and then the business end, the tiles