Anydrite screed and gypsum Adhesive

[Thehulk]

Hello Everyone,

I am about the have my new marble floor tiles laid, I thought I would investigate to make sure it's done properly, it's Anydrite screed and was laid back in mid May, there is sill some laitance on the floor which I understand will need to be sanded, it's tough to get off.

From reading it looks like a gypsum based adhesive looks like it will be the best to use on the floor, there is around 100sq metres that need doing.

can anyone recommend a good brand and good practice for this job, adhesive, priming etc. I have seen creative impressions mentioned a few times, I have also seen Kerakoll and Norcross.

Anyone who an advise and also with experience would be great

cheers

 

[Ajax123]

Re: Anydrite srceed and gypsum Adhesive

Do you have underfloor heating?

 

[Thehulk]

Re: Anydrite srceed and gypsum Adhesive

Do you have underfloor heating?

yes sorry i forgot to add this, fairly important point!!!!

Your advice would be appreciated as I've noticed you have offered a lot on this subject in the past, but I couldn't find anything a recent, perhaps things have moved from a couple of years ago

cheers

 

[Stef]

Re: Anydrite srceed and gypsum Adhesive

Listen to Alan (Ajax) on this subject as he is our resident expert & his word is gospel when it comes to these calcium screeds.
If you are laying stone then you should be looking at fitting a de-coupling membrane over ufh.
When I have been fitting to a calcium screed I have used TileMaster AnhyFix without any issue but I haven't fitted any stone on top of a de-coupler.
Wait till Alan is back on & he will advise you.

 

[Ajax123]

Re: Anydrite srceed and gypsum Adhesive

Ok... The standards recomend that natural stone is uncoupled from heated screed regard
ess of screed type. This means you should be looking at ditra or dural or similar... The heating MUST be comissioned and run and any Laitance/skin/extraneous construction debris removed ideally by sanding or shot blasting. You need to check it is dry and then I would stick the uncoupling membrane down using a gypsum based adhesive e.g. Tilemaster Anhyfix or nicobond gypfix... You can then stick the tiles down to the mat with any old flexible cement based adhesive (presumably white)

 

[Thehulk]

Re: Anydrite srceed and gypsum Adhesive

Listen to Alan (Ajax) on this subject as he is our resident expert & his word is gospel when it comes to these calcium screeds.
If you are laying stone then you should be looking at fitting a de-coupling membrane over ufh.
When I have been fitting to a calcium screed I have used TileMaster AnhyFix without any issue but I haven't fitted any stone on top of a de-coupler.
Wait till Alan is back on & he will advise you.

Ok that's great thanks for the advice I appreciate it, didn't think I would need an uncoupling membrane. Will there be any priming required before the mat goes down?

The Underfloor will be commissioned at the end of the month and run for a week ready for the floor to be done around the 10th September. Is presume once the tiles are laid, when you turn the underfloor on it should be done gradually?

 

[Thehulk]

Re: Anydrite srceed and gypsum Adhesive

Ok... The standards recomend that natural stone is uncoupled from heated screed regard
ess of screed type. This means you should be looking at ditra or dural or similar... The heating MUST be comissioned and run and any Laitance/skin/extraneous construction debris removed ideally by sanding or shot blasting. You need to check it is dry and then I would stick the uncoupling membrane down using a gypsum based adhesive e.g. Tilemaster Anhyfix or nicobond gypfix... You can then stick the tiles down to the mat with any old flexible cement based adhesive (presumably white)

I think I will prime with tilemaster primeplus and then fit the dural or ditra matting with tilemaster anhyfix.

Is the tilemaster normal flexible adhesive any good, what would anybody recommend for fixing the stone tiles onto the matting?

cheers