Tiling to gypsum based substrates/backgrounds.

[widler]

I always thought folk on here,dave especially , were into using the right materials for the right job ???
I could be wrong but i don't think skim plaster is the same chemical compound as anhyldrite screeds ??
Again i could be wrong , but why now bring out a 'gypsum' addy for gypsum screeds when we have been tiling gypsum walls, which according to some is exactly the same stuff as anhydrite ?
Im just throwing that into the mix as well [emoji15]

 

[peteablard]

The weber products I use give instructions for tiling over anhydrite screeds which IMO mean they are suitable. If they weren't suitable they would say Not for use on anhydrite or words to that effect.

 

[Stef]

The weber products I use give instructions for tiling over anhydrite screeds which IMO mean they are suitable. If they weren't suitable they would say Not for use on anhydrite or words to that effect.

Yeah Pete, it states on the back of all weber powder addy.

 

[Stef]

I always thought folk on here,dave especially , were into using the right materials for the right job ???
I could be wrong but i don't think skim plaster is the same chemical compound as anhyldrite screeds ??
Again i could be wrong , but why now bring out a 'gypsum' addy for gypsum screeds when we have been tiling gypsum walls, which according to some is exactly the same stuff as anhydrite ?
Im just throwing that into the mix as well [emoji15]

Think we need Alan to jump into this thread. [emoji6]

 

[Tile seller]

Looks like there's two ways of tiling over anhydrite screeds then,simple as that.

The big adhesive companies have there own science labs, and if they say you can prime first, then use a cement based adhesive on bases such as plaster and anhydrite (which both contain gypsum), then that's all I need to go on. where else are we to get our information? I choose to go with what's been scientifically proven to be able to recommend the correct products for given jobs.

 

[Just Rizzle]

do you guys know that weber do a anhidrite addy but only in FRANCE

 

[Just Rizzle]

anhydrite floors are here to stay and becoming more and more used . its vastly different to wall based gypsum as we all should know. theres never been any problems with skim plaster but the impurities in the floor products is what reacts with cement based adhesives and virtually no reaction to anhydrite based products. why risk it?

 

[Ajax123]

Think we need Alan to jump into this thread. [emoji6]

Nope... I'm enjoying reading it too much. My opinions are well known but when all is said and done Dave is right if you do it all by the book you can use cement addy. The gypsum addys remove the uncertainty and cater for the less perfect. Yes I know all tilers are great and do everything by the book...I have met many who have said so and yet the floors have failed. For my money why take the risk. Sand it, heat it, cool it, test it, prime it, and tile it but use gypsum based adhesive not cement.."...

 

[Dave]

You have to have a little chuckle at widler ...lol lol..


My point isn't about what should and shouldn't be used , it's if you tile to any gypsum based background , should you be using fypsum adhesive or is it one for floors and anything for walls lol..


Ray ! .. You still haven't answered my question ?


thanks for chipping in Alan , I and many many others know your views and yes we know all about switching to gypsum adhesives for anhydrite screeds , I'm asking , should they be using it on skimmed walls as well , after all in the words of another member , if you use cement based adhesives on gypsum backgrounds , you are ALWAYS got to get a reaction.

 

[Ajax123]

No need usually for gypsum adhesives on skimmed walls as long as they are primed. There's not enough moisture borne sulphate ions to promote an adverse ettringite reaction. It's all about balances and checks and molarity etc. in short you are unlikely to get much ettringite on a skimmed wall.