Tiling a room with multiple sub floors

[peterparker]

Thanks Andy.

Unfortunately your post has just alerted me to a major mistake that the tiler/builder has made

He has installed the ditra matting first with a view to installing the ufh on top. Having read your post and then looking at schluters own guidelines I see that the ufh should, as you say, go below the ditra mat.

Now where do I go from here? Is it a big deal if the ufh is above the ditra? Or do I need to get them to pull all the ditra up and start again??

Not a great start to the New Year....

 

[Spare Tool]

It's not too big a deal, you have still uncoupled the substrate, and ripping up the ditra now would probably end up pulling some of the marmox boards up. Installing the ditra just before tiling is uncoupling the tiles from everything else beneath it which is what its designed to do.
The ditra must be levelled over before fitting the ufh, then levelled over the heating wires before tiling and I would definitely use a fibre reinforced leveller, like levelflex or my favourite and a bit dearer than the rest the webber fibreflex is v good.
Tell me a builders not tiling this for you

 

[peterparker]

Thanks Andy, that's the answer I was hoping for.

You said the ditra should be levelled prior to fitting the ufh, why is that?

 

[Spare Tool]

Got a spec sheet off Ditra a few years ago and this states that electric under floor heating may be installed ontop as long as no heating cables are touching the plastic topside of the ditra, can't remember if they said why, just it musn't.. Somone else might be able to enlighten on that. I guess it could melt it, so you might need a few extra bags of leveller.

 

[Spud]

Been doing it that way for years never had a problem lol forum advice is worth the price charged be careful

 

[peterparker]

Been doing it that way for years never had a problem lol forum advice is worth the price charged be careful

Hi Gary, when you say you've been doing it that way for years do you mean putting ufh above the ditra?

Thanks and Happy New Year

 

[Rich Midge]

Bangs head against wall......pretty sure I outlined all this page 1 or 2 of this thread! HAPPY NEW YEAR!

 

[Spud]

Hi Gary, when you say you've been doing it that way for years do you mean putting ufh above the ditra?

Thanks and Happy New Year

no it was tongue in cheek Peter , as there are several people telling you to ignore the different substrates and just cover over it and tile as normal which, in my opinion is poor advice

 

[Spare Tool]

no it was tongue in cheek Peter , as there are several people telling you to ignore the different substrates and just cover over it and tile as normal which, in my opinion is poor advice

HAHA Yep OMG you've posted over 4500 times more than me, I havn't won any awards on here so take a bow. BUT I have only just joined this site and you know nothing about my training, knowledge or experiences in tiling but that doesn't mean my advice is poor!!!
just paper over the cracks and tile it, that's exactly what I said....you seriously cannot be serious that every job can cross every I and every T in "the tillers bible".
The jobs I have done 'have not failed' infact they've been featured on grand designs and in Lancashire life, I am booked up till march and I do not need to advertise anywhere...obviously I havn't a clue what I'm talking about!!!!!!!!!!!!
Happy new year all :8:

 

[peterparker]

Happy New Year everybody and thanks for not losing patience with me!

I've got myself into a bit of a muddle and just want to clarify a few things and plan how I best go forward from here.

Firstly, I'll just recap what has been done so far.

1) 22mm ply

2) 6mm marmox

3) Ditra mat attached to the marmox using using a 50/50 mix of Mapei keraquick and latex plus liquid

Was this the correct adhesive to use under the ditra?

Now I know the ufh should have gone UNDER the ditra but we are where we are. So going forward I'll use slc on the ditra, then ufh wire and then slc again.

Is this correct and should I be using the same keraquick/latex plus mix as adhesive for the tiles?

Many thanks to all for their help.

 

[Spud]

HAHA Yep OMG you've posted over 4500 times more than me, I havn't won any awards on here so take a bow. BUT I have only just joined this site and you know nothing about my training, knowledge or experiences in tiling but that doesn't mean my advice is poor!!!
just paper over the cracks and tile it, that's exactly what I said....you seriously cannot be serious that every job can cross every I and every T in "the tillers bible".
The jobs I have done 'have not failed' infact they've been featured on grand designs and in Lancashire life, I am booked up till march and I do not need to advertise anywhere...obviously I havn't a clue what I'm talking about!!!!!!!!!!!!
Happy new year all :8:

Andy check out the Schluter training courses they are free and are well worth going to it freshens up your knowledge of their products , I am sure you are a top class tile fixer and I don't question your skill or how busy you are or if jobs you have installed have failed or not but some of the advice you have posted conflicts with the manufacturers guidelines for the products you are recommending

 

[peterparker]

Could somebody tell me whether it's ok to use 50/50 Mapei Keraquick and latex liquid mix as adhesive for the tiles? The tile supplier recommended this as adhesive but I may have forgot to mention I was using ditra matting!!

Thanks

 

[Spare Tool]

Andy check out the Schluter training courses they are free and are well worth going to it freshens up your knowledge of their products , I am sure you are a top class tile fixer and I don't question your skill or how busy you are or if jobs you have installed have failed or not but some of the advice you have posted conflicts with the manufacturers guidelines for the products you are recommending

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

 

[Spud]

Could somebody tell me whether it's ok to use 50/50 Mapei Keraquick and latex liquid mix as adhesive for the tiles? The tile supplier recommended this as adhesive but I may have forgot to mention I was using ditra matting!!

Thanks

no you should not use latex plus and keraquick over Ditra , just use the keraquick or any other s1 adhesive

 

[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!!