Gyvlon/Anhydrite

[Rookery]

There's lots of info here on preparing these screeds for tiling. Sooner or later though, we'll come across one in a re-tile situation. Will it be obvious that its an anhydrite screed and will there be any extra prep other than hoovering and priming?

 

[Andy Allen]

quite a few have allready been retiled due to bad prep..

 

[Peter]

You'll know one when you see it as it's a light grey colour and could be mistaken for SLC if you weren't sure of it. Yet to tile one myself - they haven't really caught on here thankfully.

 

[Robb o]

If your not sure just get a sharp wood chiesel if its really hard to scrape into I would say its more than likely to be SLC if you can scrape the surface easily (example Plaster work) its Gyvlon.
This is not exact science and it helps if you've worked these screeds before as experience will always count.
I think that all trades will be working more and more with these over the next 10 years or so,especialy on commercial builds where block and beam floors are standard

 

[Rookery]

I've only tiled onto one so far. That was a block n beam jobby. The screed was so uneven, the builder had to slc it first :yikes:

 

[Robb o]

@Rookery

Sounds about right mate
The problem is if its not temped out properly air locks form causing failure and try to temp out to late and lumps and bumps form,supposed to be self level, quick set so you can walk on it in a day so great for site work.
Got talking to on of the screeders on a job and he was off to Dubia they always use Gyvlon because of the high day time tempretures,sand cement would dry out too quick and crack.
He reckoned he was going to make a fortune TAX FREE this was a couple of years ago.

 

[Ajax123]

@Rookery

Sounds about right mate
The problem is if its not temped out properly air locks form causing failure and try to temp out to late and lumps and bumps form,supposed to be self level, quick set so you can walk on it in a day so great for site work.
Got talking to on of the screeders on a job and he was off to Dubia they always use Gyvlon because of the high day time tempretures,sand cement would dry out too quick and crack.
He reckoned he was going to make a fortune TAX FREE this was a couple of years ago.

I think he will be sadly disappointed going to Dubai to lay anhydrite screeds due to the high temperatures...... They should not be installed at above 30 degrees c but hey ho. Also they are not supposed to be self levelling and are not sold by manufacturers as such also air locks do not form and cause failures and lumps and bumps only form if he screed starts to set before its finished ..... This gives a working window of some four hours. You must have come across some pretty poor screeders..... Oh and by he way anhydrite screeds are not temped or tamped they are dappled.....

 

[Ajax123]

He key here I guess would have to be if you are not sure treat it like anhydrite anyway.

 

[Robb o]

Thanks for the correct terminology Ajax.
As with any building site theres always good and bad tradesman working on them.

 

[Ajax123]

Thanks for the correct terminology Ajax.
As with any building site theres always good and bad tradesman working on them.

Now that I do agree with.

 

[Rookery]

He key here I guess would have to be if you are not sure treat it like anhydrite anyway.

So thats hoovering and priming, which I do anyway. Sanding?