temp of calcium screed before tiling

[J Sid]

If they told me it "SHOULD be OK" I would not use it.
I need to hear "It WILL be OK"

 

[kevinz3]

hi
no i am not going to go ahead without advice , my point was they said the surface needs to be primed to stop it coming in to contact with the screed and also said specific adhesives also need to be primed as well so the issue is the screed does not contaminate the adhesive , but why if its specific to calcium sulphate then why prime, thats all i said , if the forum is about advice etc then thats the whole point of asking is it not

 

[Sean SML Tiling]

Gypsum adhesive doesn't need to be primed as it's gypsum to gypsum. Cement adhesive needs to be primed or it will cause a chemical reaction and Debond. what happens if you trowel the floor and you damage the primer? You going to scrape the adhesive back re prime wait for it to dry then try to trowel again?

 

[Ian]

The primer should be soaking into the screed not sitting ontop (when using gypsum adhesive), the reason for a primer is really only to stop the screed drawing the moisture out of the adhesive so quickly. Yes it will seal the surface but, the adhesive will still be sticking to the screed. In the case of a cement based adhesive, the primer will be creating a barrier to stop any unwanted reaction.

 

[kevinz3]

thanks for info , so primed or no prime then if using gypsum add?? conflicting advice

 

[Ian]

Have a read of this, should answer all your questions

Broken Link Removed

 

[Sean SML Tiling]

It's always recommended to prime everything it's just a cement adhesive will react without it being 100% primed. I would use tile master anhyfix and prime with tile master prime plus mixed 4:1

 

[kevinz3]

hi
thanks of the link ,seems to explain the reason for priming as well, looks like i need to call tile masters to see where to buy it

 

[kevinz3]

only downside is the white only colour for a black tile

 

[Sean SML Tiling]

Just keep your joints clean.