Why does the bath fan duct have dried grass in it

bathroomfansvent

So I was exploring my bathroom fan setup with the intention of sending a new wire through the wall to put the fan and light on separate switches. In the process, I noticed that there’s a white plastic cover over the part of the fan that should lead to duct work, and behind that appears to be dried, dead plant matter. Note that I don’t have attic access.

What is happening here?

Could it be a rodent issue?

An exterior vent that wasn’t screened properly?

Some bizarre diy method of obstructing a duct that wasn’t properly vented to prevent moisture from going too deep?

Should I break off that plastic piece and start clearing out all the debris behind it? Or should I just close this back up, pretend I never saw anything, and just be happy the bathroom has a window I can keep open?

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Best Answer

Yes, you have a rodent or bird nest in there. No, you shouldn't break anything.

That vent flap is simply hanging on two little integral pins or arms. You can see them in the photo. You should be able to tilt the flap into alignment with the duct, then flex it to release the arm on one side.

Do your cleaning and replace the flap. Now find out why your duct is open to the outside. It should probably have mesh over the opening to prevent pest intrusion.