Hey everyone! I've just moved into a new home in California and I've been hearing this weird banging or thumping noise coming from inside the walls. It randomly happens during the day, especially when it's warm, and lasts for about 20-30 seconds. The odd thing is, it occurs even when neither the AC nor heater is running. I've checked the roof and external dampers, added insulation, and even messed around with the bathroom exhaust fans, but nothing seems to trigger it. I also recorded the noise [here](https://jmp.sh/ljeXYqFX). Does anyone have any idea what might be causing this?
3 Answers
Have you checked if it’s related to your lawn sprinkler system? When mine first kicks in, it makes a similar noise for a few seconds. Also, if you have any loose pipes in the wall, that could be causing a bumping sound when water runs through them. Just a thought!
It could be something like squirrels or even a family of rodents living in your walls! I had a similar issue before, and it turned out to be squirrels making that noise. If the pattern is consistent, it could be them getting into something or even just running around.
From your description and the audio, it kinda sounds like the noise a washing machine makes during the spin cycle. If you’ve ruled out the fans, another thing to check might be the piping. Trapped air in pipes can cause knocking sounds too. Also, consider looking into your condensate pump—it can get loud if it hasn’t been maintained.
Definitely check the condensate pump! I’ve seen them go decades without maintenance and become really noisy.
Could be! I once thought I had a ghost, but it turned out to be a squirrel family. They can be pretty noisy!