Void Behind Bay Window Roof - How bad of an issue is this?

[EinTopaz]

Hi all,

 

Was recently looking at replacing the soffits and facias over a front bay window, on closer inspection It looked like there was potentially a void in the outer skin of the wall that the soffits, facias and the roof of the bay window are covering.

I decided to take some tiles off to have a better look and did indeed find a void in the outer skin of the wall, and to my eyes looks like the void continues through the inner skin too? (though it'd be good for someone to confirm that). Based on the image and video below, how bad of a problem is this? should I get the roof off and seal this void? Reason I ask is because this bay window is for the dining room, notably the coldest room in the house. So perhaps not a coincidence?

 

 

Here's a video that shows the void well :- Hole Video Behind Bay

 

And images too:- 

 

Bay window in question 

 

 

 

 

Void behind the tiled roof.

 

 

 

 

What do you guys think? fine? or bad? or really bad?
 

thanks

 

Ged

Edited 19 hours ago by EinTopaz