What is this vent on an internal wall?

[Jakg]

Trying to modernise my spare bedroom and I've got this oddity on the wall near the ceiling.

It's on an external wall, but only appears to vent into the cavity, not through the wall. However, even with the flap in the closed position, it still lets lots of draughts in.

I think I might be better off removing it and sealing it to reduce draughts - but I don't even know what it's called!

House is a 1930's ex-council house.

Any ideas?

[Jakg]

I’ve had another look and it has a duct inside that goes right through the cavity to an air brick on the other side, so it must be for ventilating the room, not the cavity.

It’s the only room in the house to have one - the bedroom next door doesn’t.

There was a (now removed) fireplace in the room so I’m guessing it was for that?

Leaning towards removing it.

[Jakg]

Paul Drawmer said:

It's for sweeping the chimney. Well, that would have been the original use, prior to having a duct to an air brick.

Edited by Paul Drawmer on Thursday 18th January 08:27

It's 3m away from the chimney. You'd need a long brush...

Lotobear said:

That's not a soot door, it's a room ventilator - very common in public housing of that period.

I would block it up provided you have adequate vent via windows/trickle vents

It's next to a window that has trickle vents.