I am installing underfloor heating in my bathroom, on top of a new, 10mm
thick thermal underlay.
I am going to instal a back to wall WC pan on a square sheet of 12mm
external grade plywood to bring it more or less level with the area
containing the heating elements, and then tile the entire room, cutting
the tiles to fit round the WC.
I would be very grateful for advice on whether it would be better to
tile all the floor and then fit the pan on top of the tiles.
Should the plywood be sealed, and if so, with what? A PVA solution?