Failed anhydrite floor

[Ajax123]

Anhydrite screeds are made in ready mix facilities where they are subjected to quality assurance regimes. The sand used is specially selected and tested for suitability by the binder manufacturers (us). The measure of sand quality is usually determined by how quickly the screed hardens. Ergo you will prove that the sand is of good quality and suitable for inclusion in the screed by doing such a test. We already know the answer before the screed is made. Same with the binder. It is unusual in the extreme for there to be anything aims with the individual components of the screed such that standard statistical process control will take care of things. Add the sand and binder together with water and you have a screed mortar. There really isn't much to go wrong during the manufacturing process itself.

Most of the issues with screeds of all types are caused not by the screed itself but what people do with it and how they do it....

 

[the diving tile]

Most of the issues with screeds of all types are caused not by the screed itself but what people do with it and how they do it....

Thanks for that , is there any type of pourable floor that does not need sanding and sealing

 

[Ajax123]

Thanks for that , is there any type of pourable floor that does not need sanding and sealing

All screeds should be lightly abraded before applying bonded floor coverings. As for sealing it depends more on the adhesives. Some don't require a primer some do. ALL adhesives based on Portland cement will require a suitable (ideally epoxy) primer.

 

[Dougs Third Go]

from purely a tilers perspective, gypsum threads certainly seem to throw up more problems than solutions, we only seem to get answers ipso facto, ie, latching the stable door after horse has bolted. Alan this is no disrespect to you whatsoever, alone, you have stood your ground and tried to explain, at bloody long length, the merits of anhydrite, but personally the only people I can see benefitting are builders looking for a quick screed.. I'm in the minority have now (having the "know how" now) as to how to prepare and test for a anhydrite screed, but Cap'n Quick and Cheerful, down the road from me will only be to willing to tell customers that I'm talking a load of garbage and he'll do it for half the price....need I add more?

 

[DHTiling]

The only bad thing about calcium screeds is a tiler who does not make sure he/she stands their ground and insist it is dry and prepped correctly , the rest is down to the tiler , get to know the correct way with your chosen adhesive etc..

Simple as that , learn to tile to them successfully or get left behind , blunt but true .

 

[Ajax123]

from purely a tilers perspective, gypsum threads certainly seem to throw up more problems than solutions, we only seem to get answers ipso facto, ie, latching the stable door after horse has bolted. Alan this is no disrespect to you whatsoever, alone, you have stood your ground and tried to explain, at bloody long length, the merits of anhydrite, but personally the only people I can see benefitting are builders looking for a quick screed.. I'm in the minority have now (having the "know how" now) as to how to prepare and test for a anhydrite screed, but Cap'n Quick and Cheerful, down the road from me will only be to willing to tell customers that I'm talking a load of garbage and he'll do it for half the price....need I add more?

I ain't gonna give up.... They'll neverrrr tak ooor freedom.... And all that.

To be fair though I have seen step changes for the better over the 10 years or so I've been dealing with these screeds and things are probably a million times better than they were when I joined the forums.

 

[The Legend; Phil Hobson RIP]

I always ask the question "what type of screed is this?" after attending Alan's course in Durham, I realize how hard it is to distinguish the anhydrite from sand and cement just by looking at them.

I think the key is to find out who laid the screed, and what is it?

 

[Ian]

I always ask the question "what type of screed is this?" after attending Alan's course in Durham, I realize how hard it is to distinguish the anhydrite from sand and cement just by looking at them.

I think the key is to find out who laid the screed, and what is it?

I always ask now, even if I think I know what it is. Anhydrite is normally easy to spot with all the foam barriers around the perimeter. It has a yellowish colour as well.

 

[Dougs Third Go]

I always ask the question "what type of screed is this?" after attending Alan's course in Durham, I realize how hard it is to distinguish the anhydrite from sand and cement just by looking at them.

I think the key is to find out who laid the screed, and what is it?

as do I Phil, but most, won't ask as they've never heard of it, thus just assume it's normal concrete screed, and the rest, as they say, is history

 

[Dougs Third Go]

I always ask now, even if I think I know what it is. Anhydrite is normally easy to spot with all the foam barriers around the perimeter. It has a yellowish colour as well.

Bri, that's a given with a concrete screed, ie perimeter expansion joint.