Tapping Pipes

[mark_richards]

Hi

I am very new to this DIY stuff :oops: !

I have recently moved in to a new hause (new to me about 20 years old). It's only a small one bedroom and has no Gas, all Electric.

I keeping on hearing this strange noise in ceiling/wall that I can only describe as 'tapping' - it sounds like someone is tapping a nail in on the other side of the wall.

This happens every time I drain water from the sink or the bath. It doesn't happen if I run the tap with the plug in the drain, but as soon as I pull the plug out and water starts to drain the tapping starts and lasts until just after all the water has gone.

Any ideas what it could be??? :?:

Thanks

Mark

[htg engineer]

Could it just be the plastic waste pipes expanding when the hot water runs through ?