Wetroom Shower tray waste seal

[LittleJoe]

Hi
I am fitting a wetroom shower tray former which has a waste that fits underneath the tray and is pulled up tight to the underside of the tray by a metal ring on the top side of the tray that is tightened by three bolts. The shower tray itself has a plastic former built into the centre of the tray with a circular hole and a rubber ring seal fits into the hole (a bit like a grommet) so that it forms a seal with the trap as it is pulled up underneath and the metal ring above the tray as the bolts are tightened.
My question is, should I use a ring of silicone sealant on the top and bottom sides of the rubber seal to ensure no water leaks or should I use the rubber seal dry, or with a smear of silicone grease? The instructions that came with the wetroom tray and installation kit don't mention using any silicone albeit the Installation Instructions are pretty basic.
I am paranoid about having leaks once the floor is installed, tanked and tiled !!!
Any advice very welcome

 

[Madrab]

Nope ... if everything is nice and clean and new and both sides of the seal is sitting into/onto something nice and flat and clean, then no silicone would be needed.

 

[LittleJoe]

Thanks Rob.