Very weird shower noise- what on earth is causing this?

[WinifredBanks]

At my parents' house, if you run the shower for longer than about 2 minutes, the pipes or something make a terribly loud noise like a foghorn, tailing off to aloud and angry bee. This noise is loud in the bathroom, but also throughout the house.

The noise goes on for as long as the shower is running, a for about 3 minute after it stops. I can feel the floor in the bathroom vibrating when this happens. It only happens in summer, not in winter when the heating is on. Any ideas?

Is it the pump?

A healthy shower pump will stop the second the taps are turned off, but one that will soon need replacing can take longer to turn off.

Is there a hot-water cylinder fed from a cold tank in the loft?

Thanks folks. Not an electric shower. There is a hot water cylinder fed by a cold tank in the loft.

cold tank in the loft?

Cold tank with a hole in the cover for a rat, bat or squirrel to fall into, drown, then disintegrate into bits small enough to fit into the pipes and vibrate?

It will be the ballcock in the loft tank. Turn off the water and fit a new one. You can probably leave the old stem in the tank, and remove the valve by undoing just the large brass nut.

(It is possible to fit a new cone and washer to the old one and save a few pounds, but this will take longer. If you want to tinker, fit a new valve first, then take the old one apart in the kitchen table where you have plenty of light and room, and hang it up in the loft ready to swap hack next time.)

Look at the Pegler Prestex Float Valve Part 2 (£7.29 at Screwfix). Nothing else is as good. It must be a part 2 type valve. You will also need a large and a medium adjustable wrench.

Thank you very much, that's so helpful