Everytime we flush the toilet and then use either the hot or cold taps we get a loud vibration from the loft, we have looked up there and everything seems to be okay. Has anyone any idea what this might be.
It's called 'water hammer'. Androcles' diagnosis is probably closest but there is no sure way of getting rid of it without some experimentation.
Some information on it here - with some possible remedies.
http://www.practicald...ises/water-hammer.php
We have had the fog horn noise for 6 months, we had to turn on the cold tap everytime we flushed, but then very clever son visited at weekend and said it was a pressure problem, quite old house so no pressure valve on pipes so he went to Screw fix and bought a pressure valve and pipe cutter, both quite cheap, installed it and pleased to say problem fixed. Hooray
if its affecting the cold and hot water then i can only guess its going to be the jumper washer on your main stopcock, the noise travelling back up the pipwork to the loft.
Try this if it's an airlock, get a piece of hose and place over the nozzle of the cold tap (the main pressure one that comes into the house,normaly the one in the kitchen) and place the other end of the hot tap and open the taps cold first.