Tim Watts wrote:

I have to screed a concrete floor slab. Screed is going over concrete,
not over insulation. Screed depth was supposed to be 60 to 70mm, but
the slab ended up a bit thicker than intended, so in some areas, the
screed will be down to about 40mm thick.
Will a normal dry mix sharp sand / cement be OK at that thickness, or
should I add anything (like SBR etc.) Floor will be tiled.
I was going to use sand / cement in case I need to slightly slope
levels to match floors in two adjoining rooms.
Or should I consider any other type of screed ?
Cheers,
Simon.

I would have though 40mm was OK, but it's getting near the limit.


With or without screed fibres?

I've recently had 65^2 of uneven concrete screeded and I know it must be
thin in places as I had 1m^3 left over. even where it tapers of by a door
it hasn't given a problem yet though I fully expect to have to make good
with some epoxy.One chap and a laser level laid the lot in a day without
expansion joints which surprised me a bit.

AJH