primer peeling

[chequers]

Ok applied pr360 primer in three coats .first few tiles have been laid .the primer is peeling off this morning whilst picking the adhesive snobs that have squirmed out on the floor .its like a skin .not a good start . The tiles are large and it is s anhydrate floor .what will happen in the future a with the tiles or b if there is a small missed peel

 

[The D]

what sub floor is it??

 

[Brinkley]

did you allow the primer to puddle sounds like too much primer applied

 

[The D]

Did you dilute the pr360??

 

[Andy Allen]

did you remove the latience...

 

[chequers]

Hi yeah put a thick coat on .expected it to soak in .it has dried and is stable as long as you don't run anything sharp on it .it is anhydrate .the pr360 wad diluted about 4 to 1 should I stop tiling or does this mean the tiles will lift

 

[The D]

did you sand the floor ???

 

[chequers]

Done all the right prep on the surface . But I think the coats were too thick .ok what do do now

 

[chequers]

Yeah light ended the floor

 

[Andy Allen]

did you vacum the floor after sanding..

 

[chequers]

We hovered gave a light mop to get all dust let it dry then went over with a cloth .don't know what to do . It is fine walking on it and to touch but should the primer come off when you pull bits of adhesive that have been down overnight the size of a 50 p coin

 

[chequers]

Any thoughts guys advice welcome

 

[Brinkley]

dont know what to say mate is there anyway you can remove the primer with a scraper then resand ,hoover and reprime

 

[chequers]

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 .

 

[Ajax123]

Sadly there is only one option here. The primer has failed to penetrate into the screed surface meaning it was probably applied too thickly this means the bond strength either between primer coats or between the primer and screed will be very weak. You will need to remove the tiles and the primer and restart I am afraid. It is quite a common failure on these screeds and is often a case of "more is less" people put more primer on thinking it will do a better job but in reality you end up tiling on a plastic bag.

If you tile on it now your tiles will fail. At least right now you only lose a few tiles and a couple of days labour. If you had completed the job you would have lost all,the tiles as wwell.......trying to find a silver lining for you.

Why not use a primer less system instead. You will avoid this issue completely then.

Kerakoll h40 ideal, benfer gyps, gypfix from nicobond are all primer less.

 

[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.