primer peeling

[Ajax123]

Ok spoke to technical who have said that the adhesive should stick to the primer and ad long as that is happening it will be ok .

NO NO NO NO NO........ If the primer is not sticking to the floor the tiles have nothing to hold onto........... They have given you poor advice

 

[chequers]

maybe i am not explaining myself well, well i hope i,ve got it wrong .
This morning having laid one row of 800 tiles i picked off lumps of adhesive that had gone off on the floor , aside from the tiles in preperartion for todays laying ,the adhesive had stuck fast to the primer but when i forced it it came away taking the primer bit it was stuck to .
Weber say that this is right and that the adhesive should bond to the primer .
I am at a loss and worried . if the adhesive is bonded to the primer and the primer looks for all intents and purposes that is bonded to the floor apart from when you say remove a tile then the primer would come away with the adhesive .
Please comment further guys including ajax

 

[Ian]

The primer shouldn't be bonded to the floor, it should penetrate the screed and what I can gather from your explanation is that it is essentially sat ontop of it, as if it were painted on. A picture may help, so we can see what you do.

 

[andy8758]

Chequers - some photos always help in determining whats gone wrong.

I am with Ajax on this one - you will probably have to completely remove and refix.

However - you appear to be removing the tiles without a full curing period - so they will tend to come away cleanly with the adhesive and primer if you are trying to remove them within a day of laying. Most adhesives have a full curing period of 2 weeks (dependant on depth) - after 24 hours it may be "set" but not "fully cured."

 

[chequers]

Hi guys ok more investigation has revealed that the next floor up that has had one coat one of pr360 is doing the same as the floor below with two coats and the one we ar working on with three coats ,essentially it is like sunburn where you peel the skin away ,it comes off like a thin sheet ,underneath where i have peeled i have put some water and it is absorbed straight in.
Something is /has gone badly wrong ,it cannot be about putting too thick a coat or to many when all the floors are doing it with differing coats ,all of the primers have been done since Saturday ?

 

[Time's Ran Out]

For my sixpenny worth it sounds as though the primer coats are too thick and you have a skin on the surface, and there is still too much loose material on the surface of the screed.

 

[chequers]

I used a 4 to one ratio which is what i was advised by weber and what it says on the back of the bottle

I am currently taking up all the tiles ,cant really descrieb how i am feeling when i have done everything as how you should do it and i am in this position .

 

[Andy Allen]

how did you sand the floor, what grit paper did you use..

 

[chequers]

how did you sand the floor, what grit paper did you use..

I handsanded with 80 grit in accordance with what cemex said you could do which was not mechanically abrade
Ta

 

[The D]

I am at the moment turning down all floors that are on to anhydrite as I just do not trust the adhesion to this sub floor. I have sanded and primed so many floors and I have on occasion had to change a tile for whatever reason and it is always the same with the floors that are anhydrite. I brake the tile out and I can get the adhesive of the floor with very little effort. I understand that my opinion may not be very popular but it is what it is.

 

[Ajax123]

Why not change the dhesive that you use to one made from gypsum...

 

[Ajax123]

Am I beating my head against the wall. The primer is simply sat on top of the screed. It has not penetrated. This is irrelevant to the Rate of dilution. The primer should be stuck to the screed. If it is not then how in the world do you expect the adhesive to hold the tiles down. You might as well put a polythene bag on the floor and tile on that. In order to get a primer to penetrate an anhydrite screed it should be abraded with typically a sixty grit or coarser paper. 80 grit is not good enough.

Cemex screed is not anhydrite unless you are in Ireland. If you are in Ireland you are not using skin free screed so mechanical abrasion is generally the thing to do followed by a blooming good vaccuum. You say the other houses are ALS peeling. This could be for the same reason or there could be three entirel different reasons as they have al been done differently. More primer coats won't make the first one stick to the floor any better. Use a primer less system.

 

[chequers]

Why not change the dhesive that you use to one made from gypsum...

Hi Ajax and all
I cannot change adhesives as i have already purchased Weber set and ad250 two part for the floors .
The problem now is to how to get this primer off and get back to the start line .
Any ideas lads , what primer i should i go back on with then .I am glad for your help because without what you have advised me i prob would have been in a far worse position further down the road

 

[Ajax123]

if you want to give me a shout tomorrow on my mobile 07545932723 I will talk you through a few options. That will give me time to have a think.

it is Cemex S assuming you are not in Ireland it will be a hemi hydrate rather than anhydrite. hemi hydrates contain citrates which anhydrites do not so I will have a think about if this affects the pr360 and how it penetrates into the screed. I am very confident though that if the primer is simply peeling off it will needto come up. My first thought is to change the primer as I appreciate your issue with changing the adhesive. Let me think on it nd ring me tomorrow if you can.

 

[The D]

Why not change the dhesive that you use to one made from gypsum...

No thank you