Hope two posts in one day is OK? Want to try to clear up problems before winter sets in. Have a problem after using my shower and occasionally after hot water taps. After using shower a quite loud buzzing starts up and last's for about 10 minutes, sometimes stops and starts up again, sometimes sound level goes quieter then louder. Have investigated where sound comes from, I have found out it comes from the loft and from a pipe that feeds into the top of the cold water tank. When I grip the pipe buzzing stops so would appear to be vibration, but everything appears to be very tight. Any ideas on what it could be and how to rectify a very irritating noise!