Thats interesting, do you have to mix a sbr and neat cement slurry mix and spread on the floor and then add the screed as you go before it drys? or as someone else has said just dampen the floor with water?
and how long before you can tile on it what is the drying time?
just curious about the product whitebeam.
A modified sand and cement screed can go down to 25mm.
I think I would be more inclined to go with the Marmox board route, quicker, cleaner, solid Failing that Mapei Fiberplan every time