Laying large limestone tiles over UFH - TilersForums.com

[Schoolrunmum]

Hello all,
We had a wet self levelling screed floor pumped into our kitchen back in October. UF Heating has been running well since. Just ordered 900x600 limestone tiles and need advice on prep before laying them. We have been told various things, conflicting too. Do I need to seal/prime the floor? Do I need a decoupling membrane? Do I use a fast or slow drying adhesive? Do I use a flexi adhesive?
Thanks in advance!

 

[Ajax123]

I assume when you say pumped self levelling screed you mean something like Gypsol. If so...

Turn off the underfloor heating for 48 hours and carry out moisture test to make sure its dry. sand and vac the floor to remove any loose friable laitance or other contamination. Prime it using an acrylic primer and stick an uncoupling membrane down using a gypsum based adhesive. then stick your tiles to this using a flexible adhesive suitable for the application and grout with a flexible grout. clean off and seal tiles once adhesive and grout are fully dried.

the gypsum adhesive is a medium rapid setting with a pot life perhaps 40 minutes to 1 hour. on top of the uncoupling membrane rapid set or standard set is largely a matter of personal choice.

 

[Schoolrunmum]

I assume when you say pumped self levelling screed you mean something like Gypsol. If so...

Turn off the underfloor heating for 48 hours and carry out moisture test to make sure its dry. sand and vac the floor to remove any loose friable laitance or other contamination. Prime it using an acrylic primer and stick an uncoupling membrane down using a gypsum based adhesive. then stick your tiles to this using a flexible adhesive suitable for the application and grout with a flexible grout. clean off and seal tiles once adhesive and grout are fully dried.

the gypsum adhesive is a medium rapid setting with a pot life perhaps 40 minutes to 1 hour. on top of the uncoupling membrane rapid set or standard set is largely a matter of personal choice.

The guys that laid it tell me its TS40 by Gypsol, if that helps..oh, and the tiles are being delivered tomorrow, but will have to stay outside till we lay them. Snow forecast here tomorrow, is cold likely to crack them or anything?? Also, can anyone recommend an acrylic primer?

 

[Time's Ran Out]

Use a primer recommended to go with your adhesive.
Outside fine - keep off floor and covered.

 

[Schoolrunmum]

Its appears Gypsol don't make a TS 40 ! Apparently, it's Gypsol Classic...

 

[Time's Ran Out]

You are getting the limestone laid professionally?

 

[Ajax123]

The guys that laid it tell me its TS40 by Gypsol, if that helps..oh, and the tiles are being delivered tomorrow, but will have to stay outside till we lay them. Snow forecast here tomorrow, is cold likely to crack them or anything?? Also, can anyone recommend an acrylic primer?

that's interesting as TS40 is not a mix. there is TS20 and TS15 but no TS40??? how deep is it? is it on insulation?? Who Laid it??

 

[Schoolrunmum]

that's interesting as TS40 is not a mix. there is TS20 and TS15 but no TS40??? how deep is it? is it on insulation?? Who Laid it??

Hi Alan, apparently it's Classic...laid by Southern Screed..it's 50mm on Kingspan 80mm approx with wet UFH x

 

[widler]

If you can get tilemaster use there matting along with anylfix to fit it and depending on the colour of limestone use either grey or white s1 tilemaster addy .
Id personally use standard set to fix the tiles .
Screed need sanding , vacing and priming using tm primer (if you can get it, if not use which ever addy you can get hold of)

 

[widler]

Are you doing it yourself in between the school run or is a tiler fixing the stone