Liquid screed drying times

[james hailwood]

Was wondering how long until I could tile a liquid screed. I hear its 1 day per mm depth. Is that right? Any specific primer needed for liquid screed? Im tiling limestone on top of it. Thanks for advice in advance

 

[Dan]

What make is it?

 

[hmtiling]

Sounds like gypsum based to me. Any ufh? If not a mm per day believe up to a certain depth but can then be more it unusually deep. Cash be force dried with ufh. Should be sanded, heating commissioned and primed. I'd use a decoupler with stone and gypsum based adhesive under it then cement based on top for cost reasons. Loads of threads on here about anhydride/anhydrite screeds.

 

[One Day]

Sounds like gypsum based to me. Any ufh? If not a mm per day believe up to a certain depth but can then be more it unusually deep. Cash be force dried with ufh. Should be sanded, heating commissioned and primed. I'd use a decoupler with stone and gypsum based adhesive under it then cement based on top for cost reasons. Loads of threads on here about anhydride/anhydrite screeds.

ditto.
i would add though - it MUST be sanded.

 

[james hailwood]

Thanks guys, it's fibre reinforced and 40mm deep with under floor heating in it. How long is it until the ufh can get turned on to start drying it out? Once dried out sand it to a rough surface, then prime, then gypsum based adhesive then decoupler then flex adhesive?? Why gypsum adhesive and not flex cement based? Cheers

 

[hmtiling]

Thanks guys, it's fibre reinforced and 40mm deep with under floor heating in it. How long is it until the ufh can get turned on to start drying it out? Once dried out sand it to a rough surface, then prime, then gypsum based adhesive then decoupler then flex adhesive?? Why gypsum adhesive and not flex cement based? Cheers

You need to find out if it's gypsum based or traditional sand and cement screed.

 

[Stef]

You need to know exactly what the screed is or it could end in disaster.
As said above get it checked.
If you put cement based addy onto a gypsum screed & you haven't created a barrier then it's going to form entrignite crystals & pop the tiles..

 

[Old Mod]

Hope it's gypsum at only 40mm!

 

[hmtiling]

Hope it's gypsum at only 40mm!

Fibre Screed - Fibre Screed - [DLMURL="http://www.premiermortars.co.uk/screeds/fibre-screed"]Fibre Screed - http://www.premiermortars.co.uk/screeds/fibre-screed[/DLMURL]

 

[Old Mod]

Fibre Screed - Fibre Screed - [DLMURL="http://www.premiermortars.co.uk/screeds/fibre-screed"]Fibre Screed - http://www.premiermortars.co.uk/screeds/fibre-screed[/DLMURL]

UFH?

 

[Old Mod]

Fibre Screed - Fibre Screed - [DLMURL="http://www.premiermortars.co.uk/screeds/fibre-screed"]Fibre Screed - http://www.premiermortars.co.uk/screeds/fibre-screed[/DLMURL]

I believed that minimum screed depth would be the 40mm plus the depth of the pipes, making minimum depth around 60mm
And if laid on insulation it would need to be 90mm
But of course I could be wildly wrong

 

[hmtiling]

I'm getting a little confused here(not for the first time). I've never heard of a fibre modified gypsum screed. Then again, I'm not a screeder.

 

[peteablard]

The thread title is liquid screed which would suggest anhydrite. Don't just base drying times on mm per day, use that as a rough guide but make sure you do a moisture test before any tiles are laid. The one I'm on at the moment took nearly twice the amount of time to dry that it should have

 

[Old Mod]

Well I must admit that made me think too!

 

[hmtiling]

It seems you do get fibre reinforced anhydrate screeds.