We are having a large (1650 x 800) and heavy stone resin shower tray fitted on a concrete floor this week and I want to be able to ask the right questions and make an informed decision. Is a leg pack better than a wooden plinth to raise the tray above the waste, or would you use both? From what has been said so far I think the plan is for the shower tray to be placed on 4x4 wooden supports but not necessarily constructed into a plinth with supports going from side to side as well. I thought it should have a frame all the way round with 3 or 4 supports running side to side which should be attached to the frame. Which is correct? I've read somewhere that the tray then needs to be mounted onto mortar and levelled. I think the plumber may have suggested a bed of silicone but I need to double check this. Is either correct, if not how should the shower tray be positioned and levelled on the legs/plinth? One of the contractors we spoke to said the walls should be tanked, others said not. Is tanking a part of the building regs these days? I'm also wondering how on earth they are going to lift the tray into position and manoeuvre it once there to get it level given how heavy it is. How have others done this?