Mjc212

Hi all, Firstly thank you in advance for any help, new member posting but have been viewing for a while as a guest i have removed my shower tray (quadrant with riser kit) as it needs replacing want to fit a square tray in the area. I did want to fit a thin tray but as it is a concrete floor i dont think its possible? also as you can the waste has a fall down to the bend and then back up where it goes into the wall and i presume a central building waste/stack (flats) question. is there anyway to install a thiner tray or will i need a riser kit? and if i cut the waste where it comes in from the wall half way between the wall and the 90 degree bend, can i fit the trap there for the new tray?