Acrylic primer didn't bond to Larsen Tile Adhesive

Tiler87 · Oct 5, 2021

I had an issue recently that I've never seen before and any help or advice would be greatly appreciated. I used a Larsen acrylic primer on gyspum walls as instructed on product (walls had been skimmed 8+ weeks previous and moisture tested prior to sealing and tiling). 18 months later and it seems the sealer has not bonded to the wall adhesive. Wall was coated with a 12mm trowel and a standard set flexible adhesive used, the tiles are 900mm by 150mm thin porcelain and within weight limit of plaster. Tiles have now come away from the wall with 100% of adhesive on the tiles and 0% left on the wall with sealer still appearing tacky on the walls. Walls are tiled 1.2m high around the room and the issue is only where sealer was applied to gypsum walls,other walls are scratch coated and solid as should be expected. Usually removal of tiles like these should take plaster and all with it, is this is a sealer failure or am I missing something? Apologies for the long post but I'm in the trade a long time and never encountered this.
Thanks

Dave · Oct 5, 2021

Did you dilute the primer ..? As some primers need diluting and not applied neat . Or they form a skin and can fail.

Tiler87 · Oct 5, 2021

Dave said:
Did you dilute the primer ..? As some primers need diluting and not applied neat . Or they form a skin and can fail.

Hi Dave, Primer was diluted 1:1 with water first coat and applied neat on 2nd coat as instructed on the drum.

Dave · Oct 5, 2021

Ok , just had a quick read of said primer instructions and it does state as you say but more coasts can be applied if required. Do you have any white residue on tile backs or walls , as in there has been a reaction with the adhesive and the gypsum ?

Tiler87 · Oct 5, 2021

Dave said:
Ok , just had a quick read of said primer instructions and it does state as you say but more coasts can be applied if required. Do you have any white residue on tile backs or walls , as in there has been a reaction with the adhesive and the gypsum ?

No residue on either, adhesive stuck to the tile and its as if the sealer broke the bond between adhesive and wall the opposite of what it is supposed to do 🙈 adhesion to tile was excellent, the tile in question is discontinued so I used a concrete grinding disc to remove the adhesive to re-use them. Its left me completely stumped

Dave · Oct 5, 2021

Tiler87 said:
No residue on either, adhesive stuck to the tile and its as if the sealer broke the bond between adhesive and wall the opposite of what it is supposed to do 🙈 adhesion to tile was excellent, the tile in question is discontinued so I used a concrete grinding disc to remove the adhesive to re-use them. Its left me completely stumped

Was the primer fully dry before tiling as tiling to early could wet the primer and weaken the bond.

Tiler87 said:
No residue on either, adhesive stuck to the tile and its as if the sealer broke the bond between adhesive and wall the opposite of what it is supposed to do 🙈 adhesion to tile was excellent, the tile in question is discontinued so I used a concrete grinding disc to remove the adhesive to re-use them. Its left me completely stum

Dave · Oct 5, 2021

Also the plaster shouldn’t be over polished when it was skimmed.. helps the primer to soak in..

Tiler87 · Oct 5, 2021

Dave said:
Also the plaster shouldn’t be over polished when it was skimmed.. helps the primer to soak in..

Plaster wasn't over polished as when 1:1 coat was applied it darkened the skim where it was soaking in (which I understood to mean it was bonding into the ppurs) its recommended that the 2nd coat applied should be allowed to dry and become tacky before tiling

Dave · Oct 5, 2021

Tiler87 said:
Plaster wasn't over polished as when 1:1 coat was applied it darkened the skim where it was soaking in (which I understood to mean it was bonding into the ppurs) its recommended that the 2nd coat applied should be allowed to dry and become tacky before tiling

Might be best to ring technical , it’s not a primer i use and not a dilution ratio i use.. just trying to see if it was something simple..

Tiler87 · Oct 5, 2021

I Appreciate your reply Dave thank you. I had a local rep out to look at it but I know already they'll try to weasel out of it any way possible 🤷🏻‍♂

Kevbos · Oct 10, 2021

Tiler87 said:
I Appreciate your reply Dave thank you. I had a local rep out to look at it but I know already they'll try to weasel out of it any way possible 🤷🏻‍♂

To me it looks like the primer has stuck to the adhesive very well !because glued side of tiles is perfectly smooth !! The problem is when priming was done ! If you run hands down wall do they collect a fine dust !?? On very polished plaster a fine dust is left ! And I wipe over this with a damp sponge to make sure the wall is dust free !! Because guarantee that's what primer company going to say

Tiler87 · Oct 11, 2021

Kevbos said:
To me it looks like the primer has stuck to the adhesive very well !because glued side of tiles is perfectly smooth !! The problem is when priming was done ! If you run hands down wall do they collect a fine dust !?? On very polished plaster a fine dust is left ! And I wipe over this with a damp sponge to make sure the wall is dust free !! Because guarantee that's what primer company going to say

I'd say roughly 20% of the primer stayed on the tile when removed the rest was on the wall with both sides still tacky. My issue is the lack of bond, the skim coat is maximum 3mm thick so when removing a tile it should theoretically take skim and all. Walls were prepared before sealer was applied and when 1:1 mixture was painted on the skim its darkened as to suggest it had penetrated the skim and bonded. Rep came up with 3 excuses in less than 5 minutes
1. Weight of the tile was too much for the sealer/plaster
2. Coverage on tile (ridges not fully collapsed)
3. Expansion-he said larsen require a minimum of every 5 meters for am expansion joint.
So I've a feeling I'll get nowhere with then, I think the best solution is to stop using Larsen products 🤷🏻‍♂

Dave · Oct 11, 2021

Tiler87 said:
I'd say roughly 20% of the primer stayed on the tile when removed the rest was on the wall with both sides still tacky. My issue is the lack of bond, the skim coat is maximum 3mm thick so when removing a tile it should theoretically take skim and all. Walls were prepared before sealer was applied and when 1:1 mixture was painted on the skim its darkened as to suggest it had penetrated the skim and bonded. Rep came up with 3 excuses in less than 5 minutes
1. Weight of the tile was too much for the sealer/plaster
2. Coverage on tile (ridges not fully collapsed)
3. Expansion-he said larsen require a minimum of every 5 meters for am expansion joint.
So I've a feeling I'll get nowhere with then, I think the best solution is to stop using Larsen products 🤷🏻‍♂

I personally don’t agree with the tile on tacky primer recommendation. The primer is to prevent the reaction between the cement based adhesive and the gypsum. So in my experience that needs to be cured. Not tacky. I would change products imho.

Tiler87 · Oct 11, 2021

Dave said:
I personally don’t agree with the tile on tacky primer recommendation. The primer is to prevent the reaction between the cement based adhesive and the gypsum. So in my experience that needs to be cured. Not tacky. I would change products imho.

We're very limited in my area for suppliers, tile master has become available at a new local tile shop and I've been very impressed with the adhesive have you any experience with that brand?

Dave · Oct 11, 2021

Tiler87 said:
We're very limited in my area for suppliers, tile master has become available at a new local tile shop and I've been very impressed with the adhesive have you any experience with that brand?

Yes , very good gear. 👍.

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