Damp walls

[kgraham11]

In my living room there is a grate in the wall on the inside and on the outside also...I am assuming this is the damp course.air brick something or other? However, this year I have a couch under the window in front of this grate and the curtains have been closed a lot as it's so cold. I moved couch to vacuum and all around this grate it is slightly damp. Is this just condensation because it's an outside wall and I have blocked the air circulation?
It is only damp around the grate nowhere else on the wall and the grate is in the open position.
Thanks!

 

[RigidRaider]

Cold air coming into the room through the ventilation grate has cooled the area around the hole and condensation has collected.

I wouldn't fret about it, myself, as long as it's only superficial and you're sure driving rain isn't getting in.

 

[Burnerman]

I would have thought that this was a ventilation grille for a previous gas fire or similar maybe?
As its direct to the outside, the incoming air will be very cold, and chilling the surrounding wall, probably causing condensation there.
We can't recommend blocking it off if there is a gas fired appliance in the room that draws its combustion air from within the room itself.
John