can we fix ditra mat down with a gypson adhesive ?

[dexo]

we have 80 m floor to tile which has been layed for 4 weeks now and it is a gyvlon screed type it has underfloor heating which has been on for 10 days now
we would like to stick a ditra mat down to screed with a gypson based adhesive has anybody used this method as we r getting mixed comments on this help

 

[Ian]

4 weeks isn't long enough IMO, have you had the screed moisture tested? I have fixed Dural Ci+ using Creative Impressions GBTA, and it was very successful. It's the method I'd use if and when I tile to a gypsum screed in the future.

 

[bugs183]

Hi Dexo.
You will get mixed views on this Dexo, as there are many opinions about the methods of fixing to these screeds, but the lads here are all trying to get the answers.
Creative impressions GBTA is working well as an adhesive for gypsum floors, but Schluter are saying they prefer cementitious adhesives to fix Ditra.
As Bri says, don't for one minute think that having the heating on will mean the screed is dry enough. You have to moisture test as these screeds are way more sensitive to residual moisture than a traditional sand and cement screed.

 

[dexo]

hi lads i have a protometer for testing damp in plaster work will this be ok do you think

 

[bugs183]

Mmm, not according to the screed manufacturers, either a 'hair hygrometer, or one of these:
F Ball - The First Choice for Flooring Professionals - F. Ball Digital Hygrometer
Follow the instructions for how long it needs to be left in place.

 

[Peter]

Is it a possibility to use vinyl adhesive for sticking the Ditra down in these circumstances?

 

[bugs183]

Yes, this is another method that is being used.
Obviously the floor will need moisture testing, then sanding and vacuuming, before application.

 

[Pebbs]

I have done a lot of meterage on these screeds and have always used ditra matting, but that is my preferred choice and I will continue to specifiy it and install it for the foreseeable future. However I would never use anything else but Ardex AF200, again it comes down to personal choice.

Pebbs

 

[nybor62]

is it ok on gyvlon lynn ive used it on timber floors , great stuff, if it work well on gyvlon , then that would be my method of fixing

what i will say fixing ditra with floor adhesive , you can manage on you own , with the af200 , its a 2 man job esp if it s long runs ,
sticks like $ hit to a blanket

 

[Pebbs]

As long as the gyvlon has been tested and passed, we then sand it and prime it. I have never had a problem with AF200 and ditra, over these screeds. There are price implications for using the AF200, its never been 'cheap' but there would be bigger implications if the floor failed.

Pebbs

 

[Rookery]

If my memory serves me well, in the early days didnt Schluter recommend sticking Ditra down with Blue Star?

 

[bugs183]

I remember something similar when we started using it around 1994ish they did say in theory it could be stuck down with wall tile adhesive as it was designed to uncouple.

 

[Ajax123]

Not familiar with the af200 specifically but it's perfectly acceptable to use a vanilla adhesive for ditra. The only concern I wold have would be the implication on heavy point loading due to the dimples not being filled with a rigid adhesive but from a practical pontiff view is this really an issue.... Based on Lynn's comments I would suggest not.

 

[bugs183]

The adhesive would spread the same to the fleece backing with cement based or vinyl adhesive. As long as the dovetailed holes are filled above with cement based adhesive as Schluter recommend i can't see it being a loading problem.

 

[Ajax123]

The adhesive would spread the same to the fleece backing with cement based or vinyl adhesive. As long as the dovetailed holes are filled above with cement based adhesive as Schluter recommend i can't see it being a loading problem.

Question answered then methinks.

 

[Mark S]

Hi, the AF200 is a good adhesive, please do check the moisture content, I know this has been been mentioned in previous posts, but is important.
The 2 methods to test are the hygrometer box, and carbide bomb.
I would also check with Creative Impressions and Kerakoll for their advice re gypsum friendly adhesives and sticking down the Ditra