I'm replacing the concrete floor in my ground floor toilet, as the original one had subsided. I've come to the stage of either laying a 60-65mm screed or timber finish and would like some reassurance and guidance on what I'm thinking of doing.
The room is big enough to fit a corner quadrant shower and later, when funds permit, I'd like to fit underfloor heating; so for now I guess a timber floor would be best?
Except for under the shower tray, I was thinking of using bathroom grade chipboard screwed to timber battens that were bonded to the new concrete slab (now 2 weeks old) with solvent based Gripfill (of which I have several unopened tubes).
My main concern is what to fit below the shower tray. The tray destructions show it requires fully supporting except when installed on legs, which seems a bit strange. Anyway I thought I could sit the tray on 18mm marine/WBP plywood screwed to timber battens as mentioned above or screed the area below the tray and sit it on that; either way the destructions call for it to be bedded on cement mortar mixed with an anti-crumbling additive.
Another option I thought of was to bed some 18mm WBP plywood (which I've already got) coated on the underside with aquaprufe (which I've already got) on to a cement mortar or screed base?
The walls are all lightweight concrete block with sand/cement render and plaster. The concrete slab has a void cast in it to take the shower waste and waste pipe. For the time being the floor covering will be lino.
I'm not sure which way to go so any advice would be much appreciated, even a better alternative method, however, like many funds are low at the moment.