A question for AJAX.

[The Legend; Phil Hobson RIP]

Hi folks, this one is one for anyone, but Ajax is the one I hope can help me.

A couple of floors I am pricing are on the same new housing development. The substrate looked to me like Anhydrite, I asked the question as Alan always tells us to do. But after attending the exellent course in Durham that was hosted by Ajax. I still am not sure what this is, I have managed to get some info from the builders, I think it is probably sand and cement, but would like some advice.

The only info I have had is the subsrate is 75mm c35 fibre mix 10mm aggregate. If anyone could shed some light on this for me I would be very grateful.

Cheers, Phil.

 

[Gazzer]

It sounds like a standard sand and cement to me ..with fibres of course.

Identifying Anhydrite screeds becomes easier after the first, if it looks smooth, light grey and looks as if its leveller it stands a good chance.
I have had same issues when asking for details on screed though,..... "screed is screed innit ?"

 

[The Legend; Phil Hobson RIP]

It sounds like a standard sand and cement to me ..with fibres of course.

Identifying Anhydrite screeds becomes easier after the first, if it looks smooth, light grey and looks as if its leveller it stands a good chance.
I have had same issues when asking for details on screed though,..... "screed is screed innit ?"

Cheers Neale, this one has me baffled, it is pale grey and very smooth, but not as flat as you would expect from Gyvlon or the like. The builder has only given me the c35 fibre mix 10mm aggregate, which I presumed would be S&C. But I need to be sure before pricing. Cheers.

 

[DHTiling]

Are there expansion joints in it Phil. ?

 

[Gazzer]

of course Phil you need to be 100% sure. I have never seen a perfectly flat anhydrite screed yet, they tend to be rippled too unless thats just the screeders down this way ?

 

[Stef]

Are there expansion joints in it Phil. ?

The one thing I did notice about the Gyvlon I'm going to tile.
No expansions across doors,
This is a good give away.

I asked a week or so ago about identifying a calcium screed but got no replies..

 

[The Legend; Phil Hobson RIP]

Are there expansion joints in it Phil. ?

None Dave,

 

[Ajax123]

Hi folks, this one is one for anyone, but Ajax is the one I hope can help me.

A couple of floors I am pricing are on the same new housing development. The substrate looked to me like Anhydrite, I asked the question as Alan always tells us to do. But after attending the exellent course in Durham that was hosted by Ajax. I still am not sure what this is, I have managed to get some info from the builders, I think it is probably sand and cement, but would like some advice.

The only info I have had is the subsrate is 75mm c35 fibre mix 10mm aggregate. If anyone could shed some light on this for me I would be very grateful.

Cheers, Phil.

That sounds like it is probably an agilia type concrete floor which is cementitious. When finished it looks remarkably like anhydrite. It actually caught me out once on a job in Leeds beleive it or not. There are often cracks in agility screeds particularly if there are no joints but not always...

 

[The Legend; Phil Hobson RIP]

The one thing I did notice about the Gyvlon I'm going to tile.
No expansions across doors,
This is a good give away. 

I asked a week or so ago about identifying a calcium screed but got no replies..

That is what is frustrating me Stef, even the builder don't seem to know.

 

[Gazzer]

That is what is frustrating me Stef, even the builder don't seem to know.

Yup thats same here.

 

[Ajax123]

That is what is frustrating me Stef, even the builder don't seem to know.

I can say for certainty that if it has 10mm aggregate and fibres in it is not anhydrite.

 

[The Legend; Phil Hobson RIP]

I can say for certainty that if it has 10mm aggregate and fibres in it is not anhydrite.

Thanks Alan, and everyone who has contributed to the thread, as always Alan has come up trumps.

 

[Gazzer]

I would still press them for details, they should have an invoice or details for site. If not get screeders name and call him, thats what i have to do.

 

[Ajax123]

I would still press them for details, they should have an invoice or details for site. If not get screeders name and call him, thats what i have to do.

I agree. However It might not be a screeder but a ground worker depending on when it went in. Ths can be a good indicator...if it went in before the main build it is unlikely to be anhydrite. A few give away signs. 10mm aggregate, fibres (these are really fine so you have to look carefully) presence of a waxy curing agent on the surface, method of installation (normally anhydrite goes through a trailer pump where concrete us normally through a concrete pump or by direct discharge). Depth is obviously not a reliable indicator nor is colour. Presence of steel reinforcement is a good indicator as well...

Chemical tests are possible but they are a health and safety issue as they involve the use of acids.

 

[DHTiling]

I was edging on agilia , hence asking about joints as they are normally inserted at 3 mtr intervals.

But I will say an agilia screed is deffo identifiable over anhydrite or shall I say the ones I have tiled have been.

But as mentioned , always double check and if bit is agilia then the curing agents are now in the mix , instead of sprayed on afterwards.

 

[Dougs Third Go]

whenever I've been in this situation I've had the builder re-trace the paper trail, and ring up the screeders and then their suppliers to find out, it's saved my neck a couple of times

 

[Spud]

c35 is simply poured concrete Phil, c35 relates to the breaking strength per sq millimetre which is 35 newtons, 10mm aggregate is 10mm pea shingle