In addition to bees ailion says raccoons squirrels and birds have been known to get into attics and cause noises of course mice and rats can do the same.
Attic noises knocking slapping.
Clicking knocking and clanking no that s not the sound of chains rattling in the attic.
It s interesting how sounds manifest sometimes the activity of squirrels or raccoons sounds more like thumping or knocking than scratching or walking.
Knocking sound in attic if you hear a knocking sound in your attic this is a pretty good indication that an animal of some sort has taken up residence in that space.
Loose parts and refrigerant piping can cause vibration and if left unchecked can lead to a more serious maintenance issue.
In new homes roof trusses or the wood used to frame the attic often is green meaning it still has a high moisture content as it dries it can shift and contract triggering bangs loud enough to make you think a tree fell on the roof.
A humming sound generally isn t serious but it still signals that something inside your air conditioner is off.
Sometimes humming or buzzing noises point to electrical problems.
Critters just love to live in the attics of homes and the walls ceiling gaps crawl spaces etc.
If the compressor hums and refuses to.
Heating ducts as they cool also make banging noises as do.
Skittering sounds squeaks buzzes and other noises coming from your walls and attic may mean there s something living in your house that isn t part of your family.
A loose shutter on an attic window or loosened attic vents can cause a banging sound if it s windy as can branches hitting the roof.
Sounds coming from your attic could be from a number of causes pipes settling wind but the most common cause is the presence of an animal or animals in the attic.
Air passing through ducts and radiators can sometimes create a loud noise as can water passing through pipes.
This could be due to squirrels dropping nuts or wood creaking or a raccoon stamping on the ceiling.
When you hear a banging coming from the attic and are trying to determine the cause you are most likely dealing with one of these four animals.
The popping can sound rather loud as warm air expands or cool air shrinks the metal ductwork causing them to pop.
If you hear knocking noises in the attic it could be several different species.
Those noises should decrease during the home s first year or so.
A loose attic vent or shutter on a window can make a banging noise in the wind.