The difference is pressure is most commonly created by a difference in temperature.
Difference between attic and scuttle.
You can buy some poison to kill the squirrels or rats in a garden centre don t let them stay up there as they can do lots of damage to the wiring etc if they remain.
This means you should insulate between and over the floor joists.
Probably a bird or squirrels.
The bird will die after a few days if it can t get out.
Don t forget to also insulate the attic hatch.
The rule here is simple.
A scuttle attic is an attic space accessed only by a small hole in a ceiling or less commonly a wall.
For air to move there must a path hole in the ceiling crack in the drywall poorly sealed attic scuttle etc and a difference in pressure.
If ductwork is located in the attic make sure to insulate it as well to reduce heat loss and gain while passing through this unfinished space.
To make sure that it isn t just a gaping obvious hole in a ceiling it often has a removable.