What primer and adhesive - underfloor calcium sulphate

[kiteboy]

Hi all

Just wondering if there are any recommendations for correct primer and adhesive for a kitchen with underfloor (piped) heating on a calcium sulphate screed

Ive was planning on using Bal APD primer and BAL adhesive but Ive just read that BAL stuff is cement based so perhaps no good??

Thought Id ask the question before we start as Ive heared of horror stories or tiles having to be relayed - may as well try and get right first

Thanks all

 

[LM]

First you need to make sure the floor is dry.
Has the ufh been commissioned properly?
Have you taken readings to check this?
Was the laitance removed?
What tiles are you using?
BAL APD is perfect for this and their adhesive is top notch also, make sure it’s ok for the tile your using and also if you need to uncouple the floor.
Make sure you tile to the correct procedures in regards to the heating of the floor.

 

[kiteboy]

Laitence being removed soon - its been down 6 months so definitely dry now - yeh its been connected and commissioned. I didnt realize the laitence should have been removed sooner - so doing soon

They will be 600x600mm porcelain floor tiles

Uncoupling - dont know much about that but does that depend on the tile then??

 

[Dumbo]

I would decouple for the extra cost its goid insurance policy . Also with your first coat of primer make sure it isn't to thick as these screeds are normally quit dense so more thinner coats than one thick one is better

 

[kiteboy]

Oh hell - thats new - no-one has mentioned that before - its like an underlay then - is that stuck down??? Is there still a need to get the laitence off and prime it still?? Never straight forward - just been googling it - will ask my tiler what he thinks - he didnt mention it thats for sure

 

[J Sid]

could go with the bal flexbone
https://www.bal-adhesives.com/products/flexbone-2easy/
designed for your job

 

[Dumbo]

If you use a system like schluter ditra or dural ci matting yes you will need to remove Laitence and stick down . As above flexbone 2e is an option it is floating so does not require sticking down and I believe does not require Laitence removal .

 

[J Sid]

no need to remove laitence or worry about being full dry

 

[J Sid]

had the Bal rep out for a visit Thursday

 

[kiteboy]

Seems new that one - cant seem to find anywhere to buy online (in stock anyway) but will have a think and go back to tiler too - just back to the original question is bal primer or bal apd primer the way to go if we stay as is?? Again could I ask for any other recommendations for adhesive ta guys

Will defo run past the tiler though for sure - he didnt mention decoupling at all but kinda make sense to me if I can get it somewhere only need to about 20 square meters

 

[Old Mod]

no need to worry about being full dry

You can lay to a wet anhydride Julian?

 

[kiteboy]

Looking at the Bal video - they say it doenst have to be fully dry as its got holes in to allow moisture out

 

[J Sid]

You can lay to a wet anhydride Julian?

BAL Flexbone 2Easy is a unique floating uncoupling mat where no adhesive is needed underneath – a truly uncoupled system! Because it is floating, only basic preparation is needed – simply sweep solid, level floors and lay the mat. No remove of residue, bitumen or laitance. No priming needed. Tile immediately to contaminated, stained or cracked screeds and over bitumen. Fast-track tiling on new anhydrite and sand:cement screeds that aren’t cured as moisture evaporates through covering joints.

 

[J Sid]

that's what the rep said and the website backs him up.

wet....aren't cured..... Is there a difference?

 

[Old Mod]

wet....aren't cured..... Is there a difference?

Yes.