I had a similar problem: noisy hot water pipes. My problem was caused by the copper pipes being too tightly fitted in the joists under the floorboards. When they carry hot water they try to expand. But they were constrained and couldn't easily move, then they'd move in fits and starts against the joists. That movement of tight copper pipes rubbing over joists is what made the cracking/banging sounds. To fix this, I listened carefully to locate the places where these noises were coming from. It was all coming from one spot. Lifted the relevant floorboards. Enlarged the cut-outs in the joists to allow the pipes to move more freely during expansion and contraction. The new silence is really sweet. Why did I put up with those irritating noises for so long?
Trevor., March 2009
