I live in a 3 story condo building and have had very loud banging in the pipes from both my own home as well as my upstairs neighbors. The noise occurs mostly while using the hot water in the shower or bathroom sink. The noise stops shortly after cutting off the water. I had a plumber come out last week and he tells me that the noise is coming from the drainage pipe, something about it expanding when the hotwater runs through. Does that sound likely? Any suggestions? He says the plumbing cost will be about $250 (in the Northern Virginia area) but probably another $250 to repair the drywall.
Thanks for any help!