Tiling 800x800 porcelain on heated supaflo anhydrate !

[chequers]

Hi all we have a block and beam floor with underfloor heating that runs in total for approx 100 sqm.
The cemex supaflo was done 2 years ago so should have dried out , we have bought saloni 800 x 800 porcelain tiles to go down on these areas which are lounge,kitchen and hallway .
We have started to prep the floor scaping the residue and we will sand with a 60 grit sweep up and prime but what primer ? I have read about acrylic ,i think cemex installer recommended Super G but is a epoxy primer better and which one
We are having to do as much as we can due to budget .

The underfloor heating can be turned on in a couple of weeks should i put it on or leave it off .

I dont know about decoupling cost /Benefit.
The new gypsum adhesive looks good but cost is a factor so will have to go with a cement adhesive
I will contact a local tiler to do the work but need to this work myself

Any help /advice would be appreciated

Thanks
Kelvin

 

[bugs183]

This could be interesting as there are many schools of thought on this, i'm sure there will be many opinions!! I've followed various manufacturers guidelines, but not used gypsum based adhesives.

Mapei recommend Primer G with its cement based adhesives, i've used Mapei's new product called Ecoprime Grim which sticks like nothing on earth, it costs a bit more, but i have had to take a few tiles up i'd laid on an poured screed and that stuff was going no where. Go on the net and search Lilley Tile and Stone, they are selling Mapei at the best prices i can find at the mo, but i'm sure there may be other suppliers i'm unaware of.

I've also used epoxy primers as supplied by the screed providers, and this works too.
Now if you have underfloor heating i would certainly recommend an uncoupling membrane. Ditra is the industry standard, but i've had no issues with Durabase, and it is considerably cheaper. These screeds can crack, and it sounds like your rooms will be large areas, so expansion will happen, especially in door ways where an expansion strip between the door threashold is advised.
I'm sure the guys will talk about gypsum based adhesives here too.

 

[steve187]

heating needs to be on and floor warmed slowly, then switch off and allow to cool before tiling.

 

[Ajax123]

Dont sweep, vaccuum up the dust. Epoxy far betterwith cement . Screedmaster epoxy from laybond is pretty good. Gypsum not that expensive compared to good quality cement addy. Also no primer generally needed so there is a cost and labour saving. You could look at kerakoll h 40 ideal or benfer gyps as alternatives. Dont assume it is dry cos its been down two years cos it has also hd two years to get wet again. Do a moisture test. Comission and run the underfloor heating prior to tiling. I suggest unless this has been done recently you should repeat it if it was done two years ago.

 

[widler]

Gypsum based adhesive?, if its like plaster i know u can't and shouldn't use gypsum over a cement based backing, but i could be corrected on flooring .



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[bugs183]

Gypsum based adhesives are design to work with anhydrite screeds because the screeds themselves are gypsum based, which is why they do not like water or having any residual moisture left.

 

[deankyall]

am starting a anhydrite floor tomorrow,kerakoll eco ideal adhesive being used,rep even came and did the carbide bomb test as well,no primers needed apparantly and not expensive ,comparable to normal cement based adhesives and comes in 25kg bags ,so more for your £££s.using their products a lot lately seem very good ,grouts come in various colours and silicones to match,rep is going to come back at end of week too to see if we have any queries!!

 

[bugs183]

Sounds worth looking into.

 

[chequers]

Thanks for your help , dont know if the kerakoll is ok with underfloor heating ?

 

[widler]

Gypsum based adhesives are design to work with anhydrite screeds because the screeds themselves are gypsum based, which is why they do not like water or having any residual moisture left.

There u go then


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[SarahJ]

Hi chequers
I know this thread is finished now, but we about to lay our dry mix screed in a few weeks and planning underfloor by nu heat. We spotted an 800 x800 saloni pocelain tile we love and just wondered where you got yours? How did you get on with it?
Cheers sarah

 

[KerakollJohn]

Hi
Yes Ideal is ok Over underfloor heating