Looking for advice on under bay window wall issue

Members online


New Member
Hi all,

I’m looking for opinions and advice as to what the issue I am experiencing is and a solution for it.

Please see my attached photos; a section of the exterior wall under my bay window has what looks to me a damp patch (particularly worse when it rains, as it is today when these photos were taken). The second photo is inside my living room on the inside of that wall.

As you can see, the exterior wall appears to be absorbing rain water and the result is the paint on the interior wall is blistering and peeling; would I be right in thinking the issue here is the exterior render? And having the section re-rendered would solve this?

Thanks in advance for all responses.


  • 2779540C-28E1-4EC9-AB6C-F62D4C8A95A6.jpeg
    4.1 MB · Views: 215
  • 570D68B6-9AA1-4F1E-9FB4-971407D8764A.jpeg
    1.5 MB · Views: 209


Well-Known Member
Might find myself agreeing with Dollar here. Not sure about single skin but it looks deeper inside than out, and what is that brown srtuff on the wall?


Well-Known Member
Mate I quite like your comments but don't try and educate a bloke who has been fitting windows for over forty years. The drainage hole is in the bottom of the window frame and drains down to the cill and escapes at the front of the cill. The exception would be if it was face draining IE no cill.


Well-Known Member
No mate, sealant would be at the back of the cill and also across both ends of cill to stop water draining towards internal walls.


Well-Known Member
The drainage holes on a window are to the rear of your red marker. Don't push your luck I have already been courteous mate.