Best way to install shower tray

It's a wet mix, and a weak mortar. It works quite well.

The stone resin ones normally suggest bedding onto a wetish mortar mix.

I normally mix up the mortar with some SBR as an add mixture. Trowel it onto the base, and get it approximately level at about 1/2" thick. Lay a couple of bits of plastic pipe across the mix, and drop the tray onto that. Slide into final position and then pull the pipes out to drop the tray in place (its easy to do heavy trays with access from only the front this way).

Put a level on it and tap level with a rubber hammer, then leave to set having made sure the drain hole is clear and unobstructed and ready for connection.

I'll second that.

SteveW

Thanks very much both.

My shower was installed on a bed of tile adhesive, which the fitter used because it was to hand. It's been in around 15 years now, with no sign of any movement or deterioration.

So long as it confirms to the shape of the bottom of the tray and gives good support, its probably not that critical what you use.

ISTR a friend of mine did it with bonding plaster since it was what was to hand... Not so keen on using something quite so absorbent myself, but in fairness it worked well enough.

So I ended up using sand and cement. Any ideal how long it takes to set enough to stand on to tile?

Its a fairly well spread load, so a day or so should be plenty.