How to seal a bathroom basin plug and waste?

[kevNes]

My husband has changed the waste and plug in the bathroom basin.  He has used silicone to seal it but it still leaks.  What are we doing wrong

[MitchellMc]

Welcome to the Bunnings Workshop community @kevNes. It's wonderful to have you join us, and many thanks for your question about sealing a sink waste.

The most common issue I've come across is that people use the included sealing washer on the underside of the sink, whereas it actually goes under the lip of the waste on the inside. This stops the water from ever getting to the threaded section of the waste. If the seal is used under the sink and the nut compresses against it, water uses the threads as an escape route.

However, if silicone had been used on the inside of the sink, then I would have thought that it would potentially seal it.

If the seal goes on the inside of the sink, there is no need for additional silicone or thread tape. Maybe if you can take an image of the setup under the sink where the waste nut is and let us know where the sealing washer was used, our helpful members could provide further advice.

Please let me know if you have any questions.

Mitchell