Gypsum based adhesives

[Dumbo]

I as yet have not been brave enough to use a gypsum based adhesive on an anhydrate screed just wondering has anybody on here used them and if so how they have found them and most importantly any failures.

 

[hmtiling]

I as yet have not been brave enough to use a gypsum based adhesive on an anhydrate screed just wondering has anybody on here used them and if so how they have found them and most importantly any failures.

I've used Norcross tile to gypsum, Nicobond gypfix, Granfix csa and Tilemaster anhyfix. No failures and there shouldn't be if used correctly and not in wet areas. Also used Kerakoll h40 ideal which isn't a gypsum adhesive as such but is suitable for anhydrite screeds.

 

[Rich Midge]

Used Norcros and TileMaster both without any issues. TM was supplied considerably cheaper but is most likely superior imo (not a big fan of Norcros)

 

[Ajax123]

not used directly but have recommended for at least 8 years now. seen dozens of failures with cement adhesives in that time. on the other hand have only seen 2 failures with gypsum adhesive over the same period. both of those were easily explained. I don't know why you think using gypsum adhesive is a brave thing to do. It seems just common sense to me. cement on cement and gypsum on gypsum...

 

[Dumbo]

not used directly but have recommended for at least 8 years now. seen dozens of failures with cement adhesives in that time. on the other hand have only seen 2 failures with gypsum adhesive over the same period. both of those were easily explained. I don't know why you think using gypsum adhesive is a brave thing to do. It seems just common sense to me. cement on cement and gypsum on gypsum...

I never trust adhesive manufacturers fully as I have seen lots of failures on some of their products like 2 part flexible rubber crumb adhesive. And having been dumped on by bal over grout which dried out grey instead of limestone but they still claimed it was in the expected colour spectrum . So I would prefer to others who have used the product and as you know you learn more when you have problems than when everything goes perfectly

 

[Fix it Jon]

A gypsum based adhesive is fine if it is mixed correctly and the screed has been properly prepared and is dry. However if the gypsum screed has UFH in it as many of them have, then I would recommend decoupling it, so you would have to go down the cement based route.

 

[hmtiling]

A gypsum based adhesive is fine if it is mixed correctly and the screed has been properly prepared and is dry. However if the gypsum screed has UFH in it as many of them have, then I would recommend decoupling it, so you would have to go down the cement based route.

Why would you have to go the cement based route with a decoupler Jon?
If stone, i would decouple and use gypsum adhesive under and cement based on top but only switching to cement based for cost reasons

 

[Fix it Jon]

With some of the decoupling membranes they don't recommend using a gypsum based adhesive. If you are using Ditra then I believe you can use them but I would still use a cement based adhesive on top, I think the bond strength is better than a gypsum based adhesive.

 

[J Sid]

Ditra is fix with cement based or Ardex AF200 only

 

[Dumbo]

Ditra is fix with cement based or Ardex AF200 only

I've seen fixed on concrete substrate with carpet spray . Although it was curling up before he started fitting tiles