Hi everyone. Does anyone have experience with a silicone washer for the basin waste? When I try to tighten it the nut against it, it just seems to bounce back. Has anyone managed to make this work? Does it seal anyway? Should I just get a rubber one instead? I've searched the internet and can't find reference to such a thing. It's the last bit of a really complicated bathroom job. Many thanks in advance for any advice!

Nut doesn’t need to be against a sealing washer, seal should be on the basin side, not underneath. Assuming you are talking about an outlet then the seal prevents any water from getting under the lip so can only go down the hole and directly into trap. 

12 minutes ago, markc said:

Nut doesn’t need to be against a sealing washer, seal should be on the basin side, not underneath. Assuming you are talking about an outlet then the seal prevents any water from getting under the lip so can only go down the hole and directly into trap. 

UNLESS it's a basin with internal overflow, in which case the waste has a couple of holes as it passes through the basin and the sealing washer IS at the bottom.

 

A picture would help.

Ahh yes, sorry I never thought about an internal overflow

Thanks @markc and @ProDave for your input. I think it has internal overflow. I'm going to have to get the whole thing out again so I'll post a photo. The seal above was one of those foam ones and from looking at some of the other questions on this forum, they don't seem to be flavour of the month, so I might need to change that too...