How long to wait until tiling onto 75mm screed

[ashurst]

Sorry for not replying earlier to clarify.

It will be a sand and cement mix. I honk I will go with the 21 days and ditra or similar. Bal do something called rapid Matt and it's only 1mm thick whereas ditra seems to be 3mm thick. Similar prices. Which should I use ?

 

[J Sid]

ditra will let water out, bal does not. So must be ditra

 

[hmtiling]

Or durabase

 

[NZ_Tiler]

Generally what moisture content should screed have if a decoupling matt is going over?

Would it not be similar to tiling?

IMO 21 days for a screed that thick is not long enough with regular sand n cement.

 

[Dumbo]

If I remember rightly Schluter claim it can be tiled as soon as weight bearing . I stand to be corrected and if I was doing this I would obviously check .

 

[Old Mod]

If I remember rightly Schluter claim it can be tiled as soon as weight bearing . I stand to be corrected and if I was doing this I would obviously check .

The phrase they like to use is,
'as soon as its mechanically repairable'
Tape the joints for moisture sensitive stone, otherwise not necessary, but certainly doesn't hurt, personally I'd prefer it.
But yes as soon as its load bearing.

To fast track a screed a 'vapour equalisation barrier' must be used i.e.
Ditra 25
Durabase mat

These mats are not for wet ufh obviously, but they still do the same job as above.
Ditra E Heat mat
Variopro ufh mat.

 

[slythetiler]

i treat S&C screed beds over UFH the same way as concrete 1 week per inch to dry, so at 75mm i would leave at least three weeks and not force dry it by using the UFH. I prefer to let it dry naturally. Then go with Ditra or durabase for crack suppression.

 

[gazmcd72]

You could always use bal green screed if time is an issue

 

[Flintstone]

You can tile on a green screed after 28 days using tilemaster ultimate but that doesn't offer any uncoupling if you want that.

 

[hmtiling]

Think bal green screed is 48hours. Most s2 adhesive are good for green screed too

 

[Andy Allen]

Is green screed flexible enough for the ufh..?

 

[Old Mod]

Is green screed flexible enough for the ufh..?

Maybe not on a green screed.

 

[Flintstone]

you could probably used ultimate to stick crack mat down then tile with ultimate on top of that. Cheaper than ditra

 

[Flintstone]

I would Always want to put some sort of uncoupling on a green screed

 

[Old Mod]

you could probably used ultimate to stick crack mat down then tile with ultimate on top of that. Cheaper than ditra

Antifracture mats are not suitable for use as a vapour barrier Andy, needs to be a product similar to Ditra or Dural. They allow moisture to escape via the cavities.