I have three bathroom sinks on the 2nd floor of my house. 1st and 2nd sinks are in the master bathroom, the 3rd sits in the other bathroom directly behind a wall (in other words, 2nd and 3rd sinks are separated by a wall). These two sinks separated by a wall experience loud banging. I think they are fed by the same hot water pipe because the 1st sink in the master bathroom never has this problem. The problem occurs about 1-2 minutes after running the hot water faucet: the pipes start banging behind the walls. It is deafening. Under one sink I can even see the hose feeding the faucet from the hot water valve literally jumping up and down. FYI this never happens with one sink in the master bathroom, nor any of the two showers on the 2nd floor. Only the 2 sinks separated by a wall. It stops immediately after shutting off the hot water. I investigated in the basement as well. When running the hot water from those 2 sinks I feel the vibration above the hot water heater, but don't think it's related to that site (it doesn't happen at any other sink in the house).
How do I fix this? From what I can see behind these two sinks, the pipes look pretty well tethered to the joists. I don't see any vibration except at the hose, but know the hose can't be making all that noise. How do I fix this without tearing up my entire 2nd floor walls?
If I can't fix it, and just decide to live with the annoying jackhammering, does this set me up for damage down the line to my pipes in 5 or 10 years? Do I have to fix it?