: I've noticed a ticking sound coming from the wall above my kitchen sink. It's a single story, and there's a vent stack on the roof corresponding to where I hear the noise. I only hear the noise after running some water. I've especially noticed it when the dishwasher drains. The drain and vent pipes are plastic. I've heard that this noise could be caused by the pipe expanding and contracting, rubbing against something. Is this possible? Could the vent pipe expand and contract, even though there is not technically water running through it? If this is the case, what can I do?

Mark,
Water running down any length of plastic pipe can cause expansion and contraction.
Holes should be drilled straight and allow movement of the pipe.
I have seen pipes wedged in with shims, or strapped with metal plumbers tape.
I've seen crooked holes with pipes that bend to make it through.
You can live with the ticking, or remove the wall and located the "binding" portions of the pipe and wall studs. Terry