Bath waste and trap fitting

Hi All,

This may seem like a noddy, stupid question but its driving me round the bend I'm in the process of re-fitting our bathroom. Put the bath in at the weekend and connected up all the plumbing for the taps and shower and stuff... I'd already sealed the waste into the bath and tightened up the backnut to seal it to the bath (or so I thought!)

How the hell do you get the backnut tight enough to seal?! No matter what I do, I can't get it to seal. I have a thin 3mm soft rubber washer directly under the bath, then the overflow banjo, then a thick 6mm rubber washer and then the backnut. I can't for the life of me stop it weeping slightly from between the overflow banjo and the thick rubber washer I'm tempted to take it all off and sandwich it all with silicon sealant but I don't think that is the best way - or is it?! It's almost as if the rubber washer is too rigid/hard to compress and form a seal. I have PTFE on the thread to help that seal - seems to work.

What am I missing?! It's driving me round the bend and I don't think I can take another night lying on our bathroom floor staring at the waste and trap!! Or am I just being weak?

I have a thin 3mm soft rubber washer directly under the bath, then the overflow banjo, then a thick 6mm rubber washer and then the backnut.

Click to expand...

put a poly washer under the 6mm rubber one you are twisting it as it thightens hence the leak

kevplumb said:

I have a thin 3mm soft rubber washer directly under the bath, then the overflow banjo, then a thick 6mm rubber washer and then the backnut.

Click to expand...

put a poly washer under the 6mm rubber one you are twisting it as it thightens hence the leak

Click to expand...

Wow - were you typing the reply whilst I was typing my question?!

Ok, just to make sure as I really can't face this any more nights - I need to get a poly washer (i.e. a harder plastic type to the layman!) so the backnut can tighten up against that without twisting the rubber washer. Excellend - I was convinced Silicon wasn't the answer even though it was getting very tempting! In retrospect, I could see the washer and banjo turning and didn't think that was right but its bloody difficult to hold it all still and get the leverage on the backnut.

Thanks very much

Am not surprised you are getting a leak with this type of bath waste- they are cr*p , really. Like you say the issue is with getting the backnut tight enough to make a seal against the banjo 'spacer'.

I would junk it in favour of one of the ones with the centre screw fixing (no backnut) They are just as cheap and are easier to fit . Never had a leak with one yet.

wizbongre said:

Ok, just to make sure as I really can't face this any more nights - I need to get a poly washer (i.e. a harder plastic type to the layman!) so the backnut can tighten up against that without twisting the rubber washer. Excellend - I was convinced Silicon wasn't the answer even though it was getting very tempting! In retrospect, I could see the washer and banjo turning and didn't think that was right but its b****y difficult to hold it all still and get the leverage on the backnut.

Thanks very much

Click to expand...

Don't over tighten, those banjo type wastes crack easily. Just ask for a poly washer for a bath waste at your local plumbers merchant. I never use silicone on rubber washers as it makes the washer miss-shape when tightening, i use plumbers mait on those wastes.

Steady said:

Am not surprised you are getting a leak with this type of bath waste- they are cr*p , really. Like you say the issue is with getting the backnut tight enough to make a seal against the banjo 'spacer'.

I would junk it in favour of one of the ones with the centre screw fixing (no backnut) They are just as cheap and are easier to fit . Never had a leak with one yet.

Click to expand...

Not thought of that - the screw fixing I put on the new kitchen sink worked first time no problems... Thing is, we have gone for a pop-up type plug/waste so I can't fit the screw unfortunately otherwise that would have been a good option.

Lee-King said:

Don't over tighten, those banjo type wastes crack easily. Just ask for a poly washer for a bath waste at your local plumbers merchant. I never use silicone on rubber washers as it makes the washer miss-shape when tightening, i use plumbers mait on those wastes.

Click to expand...

Thanks for that - is plumbers mait a kind of caulk or something, similar to PTFE paste or the like or jointing compound? So it holds a seal but doesn't set solid and make removal impossible? IF so it sounds like the answer combined with the poly washer.