Tiling a room with multiple sub floors

[Spud]

Sincere apologies Gary, I have just got up with a banging head and read back my post at 1am this morning which was very much alcohol fuelled, infact its cringe worthy embarrassing and I don't know what the hell I was thinking...
I was only trying to help the guy to the best of my knowledge get his floor tiled.
If as you've pointed out I've given duff advice this was just how I'd do the job and the spec sheet I had from schluter could be way out of date and things change so I guess well I probably do need to take a look at updating some of my technical knowledge before posting on this subject again.
Could you please highlight the points I am wrong on
Regards Andy

Please don't stop posting Andy all tilers are welcome on the forum and you will know loads of stuff that others including me don't know , everyone has different methods and tips and I have learnt loads from coming on here and the other forums

 

[Alphadock]

Schluter ditra heat has the heating cables on top, and are held in place by the plastic?
If this was my job I would marmox over the whole floor, this will act as an uncoupling and solve the problem of different substrates. Then heat mat and tile. Latex over the cables if you like.
Ditra mat over marmox is overkill/unnecessary in my opinion.

 

[aflemi]

Schluter ditra heat has the heating cables on top, and are held in place by the plastic?
If this was my job I would marmox over the whole floor, this will act as an uncoupling and solve the problem of different substrates. Then heat mat and tile. Latex over the cables if you like.
Ditra mat over marmox is overkill/unnecessary in my opinion.

Sorry, are you saying that Marmox, apart from being an insulating and tilebacker board also has a decoupling function? Never heard that one before..

 

[White Room]

Schluter ditra heat has the heating cables on top, and are held in place by the plastic?
If this was my job I would marmox over the whole floor, this will act as an uncoupling and solve the problem of different substrates. Then heat mat and tile. Latex over the cables if you like.
Ditra mat over marmox is overkill/unnecessary in my opinion.

How can Marmox be a decoupling when both surfaces are rigid which allows no movement...

 

[Alphadock]

I believe it is a decoupler.
Both surfaces are rigid, the foam between them gives it the decoupling. ie it's not one rigid surface.
I could be wrong and happy to be proved so.
Is there a rep from marmox/week/orbry/jackoboard on the forum?
I may drop an email to marmox to check?

 

[Alphadock]

http://www.marmox.co.uk/products/marmox-waterproof-insulation-board

Second paragraph..........

 

[White Room]

I'm staggered at that statement from Marmox, they state it on their site so fair play but my brain has just gone onto overload, read their site before and must of missed that.

Just to add, I bet schluter would have something to say about it.

 

[Spare Tool]

Sure i actually mentioned somewhere in this thread that insulation boards do infact help to uncouple a floor, but imho it is no substitute for a dedicated uncoupling membrane...ditra heat matt is a totaly different make up to standard ditra and i stand by the technical fact sheet i have that states the ufh wires must not touch the top of the standard ditra....
I did however email schluter for my piece of mind and they stated that expansion joints 'must' be fitted at the exact point where the different substrates meet, so hold my hands up n say i was wrong on that point, but this kitchen floors gonna look a right dogs dinner with expansion joints cut skew wiff all over the place, sometimes you just simply cannot do everything to the rule book

 

[Alphadock]

On the subject of not doing things "by the book", I had this same 'timber meets screed' situation at my in-laws.
Instead of putting an expansion joint where the two substrates met, I had a tile span the joint and bedded the screed side with adhesive as normal and spot bed the timber side of the tile with Silicon.
Now this may be bad practice but there's no arguing when 8 years later the floor is still perfect.
They were just a ceramic tile and no ufh though.

Back to the original post, how do you mean "schluter might have something to say about it"?

And
If marmox say their product is an uncoupler (dedicated? Or not)who are we to argue, surely they've researched and tested this claim a lot more than any of us!

 

[peterparker]

Well Mapei disagree with you (and Schluter). Schluter say you should NOT use a modified adhesive because it needs air to 'cure' but none can get through the tile or ditra.

I had a long chat with Mapei technical department and they were adamant that this was nonsense and Keraquick + latex liquid was what they would recommend for 90 x 90 tiles and these circumstances.

Confusing to say the least!!