tiling Is a decoupling membrane needed with liquid screed + wet UFH + porcelain tiles?

[Jeezeeh95]

Building a new house and next is insulation & wet UFH, followed by liquid screed (then wait 28 days before tiling)

 

We'll be tiling all of the ground floor with the above set-up (wood effect porcelain tiles 120cm x 20cm) across 101m2 of floor area downstairs, however I'm not sure if it's necessary to spend £1k for Ditra Mat or some kind of membrane as well?

 

Some tilers said I do, but most have said it's not necessary if using liquid screed - my questions for you guys are:

 

• Do I need a decoupling membrane? If so, which one would be best for my set-up as there is a lot of choices (Dira, Durabase, Mapetex, Strata etc)
• Is there a special kind of adhesive I need to use with liquid screed? (e.g. Kerakoll H40 Gel Adhesive etc)
• Apparently liquid screed creates a layer on top which needs to be sanded down, is this required or can a membrane be laid straight on top?

 

Any help appreciated!

[JohnMo]

10 minutes ago, Jeezeeh95 said:

liquid screed

You may need to include the screed type as the screed make up will affect the answers you receive I suspect.

[nod]

No

Thats the whole point of liquid screed 

 

[Beau]

We had an anhydrite liquid screed and tiled straight on to it. I did have to grind the top and prime it but no decoupling membrane which sounds weird as surly you need the tiles bonded to the floor anyway 

Edited April 9, 2025 by Beau

[nod]

To be fair 

I tile a lot of commercial jobs in traditional screed that have no decoupling Matt and most liquid screed are tiled within a week of being poured 

Hardly ever any problems with modern adhesives