Hole in breeze block inner wall: leave or fill?

[mike004]

My house is 70s construction: breeze block inner and brick outer.
I was up in my loft the other day, checking out my water tank, and noticed that there was a cricket-ball sized hole nearby in the breeze block gable wall. I could look through and see the brick layer. Presumably a large chunk of mortar has fallen out at some stage, though I couldn't see it on the loft floor anywhere.
I am undecided whether this hole needs filling up? Maybe if I leave it it would provide some fresh air up there, or maybe it would be a channel for warm loft air hitting the cold external brick layer.

 

[Ivor Windybottom]

It will make absolutely no difference to anything. The loft's unheated so is essentially full of the same semi-cold air as what's in the upper part of the cavity and outside.

Its main purpose is to support the outer skin via the wall ties. If it wasn't there then the outer skin would blow down. It possibly provides some roof support too.

A hole will not matter at all.

 

[mike004]

It will make absolutely no difference to anything. The loft's unheated so is essentially full of the same semi-cold air as what's in the upper part of the cavity and outside.

Its main purpose is to support the outer skin via the wall ties. If it wasn't there then the outer skin would blow down. It possibly provides some roof support too.

A hole will not matter at all.

So I should not be worried about warmer air from the loft inside condensing on the outer brick wall?

 

[noseall]

My house is 70s construction: breeze block inner and brick outer.
I was up in my loft the other day, checking out my water tank, and noticed that there was a cricket-ball sized hole nearby in the breeze block gable wall. I could look through and see the brick layer. Presumably a large chunk of mortar has fallen out at some stage, though I couldn't see it on the loft floor anywhere.
I am undecided whether this hole needs filling up? Maybe if I leave it it would provide some fresh air up there, or maybe it would be a channel for warm loft air hitting the cold external brick layer.

Foam it, and any other suspicious looking holes or gaps. Don't foam the soffit vents though.

 

[^woody^]

So I should not be worried about warmer air from the loft inside condensing on the outer brick wall?

Just like it condenses on the cold roof felt?

Don't over-think things