Discuss What primer and adhesive - underfloor calcium sulphate in the Adhesive and Grout area at TilersForums. USA and UK Tiling Forum

kiteboy

TF
Reaction score
4
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
 
L

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.
 
OP
kiteboy

kiteboy

TF
Reaction score
4
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??
 
D

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
 
OP
kiteboy

kiteboy

TF
Reaction score
4
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
 
Last edited:
D

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 .
 
OP
kiteboy

kiteboy

TF
Reaction score
4
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
 
J

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

J Sid

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

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

One Day

In 12 years of tiling and my fair share of calcium-sulphate screeds, how many would I say were suitable for an unbonded installation?
1 or 2 at the most.
 
D

Dumbo

Me and harry would be ok we have a quality screed installer down here . Each one is bang on . As regards moisture it says 1.5 %cm I expect that's the same as by volume . Just wonder what it is rh as that is what most of us will measure by .
 

judge

TF
Supporter
Arms
Reaction score
351
Me and harry would be ok we have a quality screed installer down here . Each one is bang on . As regards moisture it says 1.5 %cm I expect that's the same as by volume . Just wonder what it is rh as that is what most of us will measure by .
I asked the bal rep what rh is acceptable for the flex one when I met them at my local topps to which he replied he wasn't sure.he said he would get back to me (about five weeks ago) .even though it's been tried and tested on the continent for the last ten years(I think) ?I'm still a little optimistic about it
 
H

hmtiling

That's not really the answer . I think schluter say 2%by volume with a cement based adhesive and I've never been able to find out what that is as a rh figure .
Rh changes with ambient temperature. It's a little confusing to me. Not the hardest thing to achieve
 
J

Just Rizzle

ive never used and will never use any cement based adhesive on a anhydrite floor.i must of done 50 plus floors which are anhydrite based, i always use tile masters anhyfix.to ether fix tiles or decoupling mat once mat is laid you can use a cement based adhesive
 
D

Dumbo

ive never used and will never use any cement based adhesive on a anhydrite floor.i must of done 50 plus floors which are anhydrite based, i always use tile masters anhyfix.to ether fix tiles or decoupling mat once mat is laid you can use a cement based adhesive
I did an alpha hemi hydrate screed where I had to put a cut tile until the next stage of work was completed . When I had to remove said tile to continue tiling , it didn't want to come up , it was well bonded to the screed and that was done with a cement based adhesive .
 
J

J Sid

isn't the problem a long time reaction between gypsum and cement where the two touch, could take years to fail ?
 
D

Dumbo

isn't the problem a long time reaction between gypsum and cement where the two touch, could take years to fail ?
isn't the problem a long time reaction between gypsum and cement where the two touch, could take years to fail ?
Actually I thought it was the other as when both parts were inert ie finished curing that was it . Obviously some things although may not have a good bond from the get go may take time to show the problem . I couldn't see how dry anhydrate and dry cement is going to start reacting maybe @Ajax123 could share some knowledge on this .
 
J

Just Rizzle

I did an alpha hemi hydrate screed where I had to put a cut tile until the next stage of work was completed . When I had to remove said tile to continue tiling , it didn't want to come up , it was well bonded to the screed and that was done with a cement based adhesive .
how long was it down?
 

Reply to What primer and adhesive - underfloor calcium sulphate in the Adhesive and Grout area at TilersForums.com

Or checkout our tile training advice or the Tile Standards

This website is hosted and managed by www.untoldmedia.co.uk. Creating content since 2001.

Replies you've not seen

UK Tiling Forum Stats

Threads
66,583
Messages
866,612
Members
9,500
Latest member
Dazzer
Top