Membrane required or not

[Md10]

Hi

I am looking to lay porcelain tiles in a bathroom with wet underfloor heating. The ufh has been commissioned. The floor is a liquid screed and the Laitance has been removed. The screed got pumped in about 4-5 months ago.

Can I tile straight on to the floor and using a primer or should I an uncoupling membrane like Schlüter-DITRA?

If it is the latter what would I use to stick the membrane to the screed? Can I use flexible tile adhesive?

Sorry if this topic has come up before but I can’t find a definitive answer.

Thanks in advance

 

[Albert]

Hi

I am looking to lay porcelain tiles in a bathroom with wet underfloor heating. The ufh has been commissioned. The floor is a liquid screed and the Laitance has been removed. The screed got pumped in about 4-5 months ago.

Can I tile straight on to the floor and using a primer or should I an uncoupling membrane like Schlüter-DITRA?

If it is the latter what would I use to stick the membrane to the screws? Can I use flexible tile adhesive?

Sorry if this topic has come up before but I can’t find a definitive answer.

Thanks in advance

I don't understand. What screws, if it is a liquid screed.

 

[GoneGuy]

You don’t need screws

 

[Md10]

I don't understand. What screws, if it is a liquid screed.

Sorry that’s an auto correct on my phone. What do I use to stick the membrane to the screed. 🤦🏽‍♂️

 

[Albert]

Still need a bit more information, what type of liquid screed?

 

[J Sid]

Ardex AF200 plus to fix ditra

 

[widler]

Its not industry standard to fit matting with porcelain tiles, its entirely up to the customers of mine if they want it .
Ive been qustioned on it when recommending it before as he read its not needed and thought i wanted more money for fitting out of the job, but also ive had them say they want it for ‘peace of mind’.
So i would recommend you have a good read up about Aladdin's carpet
But im taking it its not a large area so wouldn’t break the bank

 

[J Sid]

A bit of a statement Craig 😁
Did you mean British Standard rather than industry standard?
I think we need to know what sort of porcelain tiles are going down

 

[demi34]

First you have to take of 1mm liquid screed and then primer 2 coats 1-2 and 1 neat primer after that bal rapid mat

 

[Ajax123]

1mm off the liquid screed? Where did you get that bo**ocks from?

Remove laitance make sure screed is dry and underfloor heating commissioned. Prime the screed with prime plus or similar. Stick ditra (or similar) down if required with anhyfix or similar (gypsum based adhesive). Stick tiles to mat with cement based flexible adhesive. If no Ditra then stick tiles down with anhyfix.

1mm? I'd like to see you try measuring that...

 

[widler]

I thought it was tiling standards/british standards same thing, no matting required with porcelain tiles @JulianSidney ?

 

[J Sid]

I thought it was tiling standards/british standards same thing, no matting required with porcelain tiles @JulianSidney ?

I think British Standard is compiled by a few old men and industrial standards is what I commonly do 😁

 

[Md10]

Still need a bit more information, what type of liquid screed?

This is what I have from the person who installed it.
“self-compacting anhydrite floor screed”

If it helps I have a block and beam floor then insulation then screed. There’s some damp proof in between too.

 

[Albert]

This is what I have from the person who installed it.
“self-compacting anhydrite floor screed”

If it helps I have a block and beam floor then insulation then screed. There’s some damp proof in between too.

You need a gypsum-based adhesive to fix the ditra after first removing any laitance
or you could go with ball Flexi bone