Wetroom Prep on anhydrite floor

[kaharrison9]

Evening All

I know the briefest of details but I'm off to see a customer tomorrow where by the sounds he is having wet trays set then the screed poured to the required height.

Has anybody any experience of this, pit falls, tips, waterproofing, etc.

Apologies a bit lacking in detail but should know more tomorrow.


Cheers.


Kevin

 

[White Room]

Did'nt think those screeds were suitable in wetrooms...

 

[Ajax123]

Not sure if you mean the screed is forming the wet room floor or the tray is the wet room floor and the screed poured up to it to form the "flat bit"next to the wet room area. I would not normally recommend these screeds in a wet room application but provided they are dry they can be dealt with to make them suitable. You will need to allow it to dry, commission any underfloor heating and then tank the bejeezers (I like that phrase, I might use it in my technical data sheet) out of it as you will need to keep the moisture out. Once it is fully tanked and waterproofed you should be able to treat it like any other screed.

Anhydrite screeds are not normally laid to falls, well not in purpose anyway, although it can be done with care. I would be interested to know how they intend to get the falls or is that what te wet room tray does??

 

[Just Rizzle]

did a new build last year with 3 wetrooms they used 1200 by 900 wedi trays surrounded by ufh in anhydrite.sand of laytence fullycover floor in ditra matting stuck down with anhydrite addy by tilemaster tanked out the walls using kerdi matting1 mt fully round room and to ceiling in the wet area all rooms were large so created falls by using laytex levellers . the job was a dream to do used jura limestone on walls and floors that was in sept last year went back in feb to discuss futher work as client delighted with all the work we done in the house.
get used to anhidrites guys as this is the future more and more builders using it. got a 200 mtr floor to do in 60 days time as anhydrite layed last week

 

[Time's Ran Out]

From above post :
'Latex levellers to form the falls over the Ditra then fix the Jura Stone.'

Do Ditra recommend such a build up of latex on top of the Ditra?
I was always under the impression that the tile was adhered direct to the Ditra surface and all preparation was under the decoupling .
Is there a maximum thickness on top of Ditra that they will recommend!

 

[kaharrison9]

Will have a better idea today.
It does sound Alan that the trays will be set at the correct height then the screed brought up to the height and around the trays.

Obviously wet floors and anhydrite not the greatest of combinations but I was thinking of running the ditra on the floor and lapping onto the tray.

 

[Old Mod]

[MENTION=11380]timeless john[/MENTION], I had to ask the very same question recently John, whilst Schluter prefer all prep below, a max of 5mm seemed to be the answer for latex on top of Ditra.

 

[Ajax123]

Will have a better idea today.
It does sound Alan that the trays will be set at the correct height then the screed brought up to the height and around the trays.

Obviously wet floors and anhydrite not the greatest of combinations but I was thinking of running the ditra on the floor and lapping onto the tray.

that works for me but I think I would still tank the floor out to maybe half a meter or so of the tray

 

[kaharrison9]

There are 4 wet trays to go in and the screed is around 75mm thick.

The plan is to box out where the trays are going and pump in the screed.

Once dry set in the trays at the required height.

Usually anhydrite prep.

Ditra down on the floor with Gypfix up to the tray and taped between tray and Ditra

 

[Just Rizzle]

why cut the ditra round the tray and tape

There are 4 wet trays to go in and the screed is around 75mm thick.

The plan is to box out where the trays are going and pump in the screed.

Once dry set in the trays at the required height.

Usually anhydrite prep.

Ditra down on the floor with Gypfix up to the tray and taped between tray and Ditra

why create a problem tank over the tray the less joints in the floor the better.

 

[Ajax123]

You should advise them to address the screed depth. 75mm is far too thick. It will add over a month into the drying time. With underfloor heating they only need 45 to 50mm. By all means put them in touch with me and I will tell them. They can put a layer of insulation down to reduce the screed depth. Or just drop the finished floor height.

 

[SJPurdy]

why cut the ditra round the tray and tape

why create a problem tank over the tray the less joints in the floor the better.

The Ditra will not bend to the different slopes of the moulded trays and so a change in type of waterproofing is required.