Rattling cold water feed to tank

[Jameswren]

I have a pipe making a loud rattling noise when I use a cold water tap off mains - it started yesterday and had never done it before.

The pipes are not accessible until they reach the loft.

Any idea of the cause? How can I fix it?

 

[PrenticeBoyofDerry]

Is this any cold water tap or just one.
What you are describing is water hammer, normally happens on high pressure systems when valves/taps are being closed quickly or if you have loose pipework that requires clipping.
It could be down to a faulty tap value, if there is no history of this previously.

 

[Jameswren]

Thanks for the reply

The Mrs called to say water was coming from the loft a seems like a faulty ball valve and badly fitted overflow combined.