Anhydrite Screed

[widler]

This is all well and fine , is this not the old
'ive done it for years and never had a problem' senario ??
again, remember pva , it was fine to tile onto for years, but now 😉

You watch, in a year or two they will tell you that you can't use cement addy on gypsum screeds 🙂

 

[Ian]

This is all well and fine , is this not the old
'ive done it for years and never had a problem' senario ??
again, remember pva , it was fine to tile onto for years, but now 😉

You watch, in a year or two they will tell you that you can't use cement addy on gypsum screeds 🙂

I'm with @widler on this one, why would the adhesive manufacturers spend £1000's and goodness only knows how much time developing products specifically for these screeds, if something they already produce is perfectly suitable?

 

[StevieBoy]

Guide: Tiling On Anhydrite Floor Screed | Palace Chemicals Ltd

 

[widler]

Ok im giving up, i will use gypsum addys made for the job, you lot stick it to neat primer

 

[StevieBoy]

Lol

 

[AD Ceramics]

In theory is it not just like tiling on a plastered wall, you prime that to form a barrier between gypsum and cement? Who u uses these adhesives on walls?

 

[Just Rizzle]

if you reed the palace recommendations and all the other cement based addy manufacturers, what they are saying is to put a barrier between the addy and the screed so the addy sticks to the barrier not the screed.
with the gypsem based addys they are bonding with the screed not the barrier so forming a better adhesion so making the tiles more secure to the floor and in my honest opinion less likely of failing ,and less likely of you getting a call back from your clients

I understand a recent program on grand designs has had a failure where the tiler fix on anhydrite using a cement based addy

 

[widler]

In theory is it not just like tiling on a plastered wall, you prime that to form a barrier between gypsum and cement? Who u uses these adhesives on walls?

Not really as you can skim onto s/c roughcoat with no problems , completely different substrates , if they were the same they would just pump multifinish onto the floor

 

[widler]

Shoot, ive posted again, bloody still askeep

 

[Tile Shop]

But the whole point is that because the screed is porous the primer will key in. If thats well bonded to the surface there won't be any issue of it coming loose or failing. So it will prevent the gypsum reacting with the cement but the adhesive is still sufficiently stuck down.

I mentioned in a previous post 2 possible pitfalls of using the anhyfix, gypfix or whatever your weapon of choice is, and the users of it didn't jump up to defend it.

Crystalisation occurs when gypsum comes into contact with cement yes? My first point was that grouts are cement based and will come into contact with the adhesive...... see the possible problem?

Next, you can't afford for the addy to get wet. So never mop a floor again?

I am going by what i've been told tech-bods from several places. So i'm 100% behind the cement and primer because we know it works.... but i'd love someone to now defend the gypsum addy's and tell me i'm wrong, then maybe i'll have the confidence in selling the stuff.