Brickwork leaking onto paint?

[tntcoder]

Hi,

I've recently painted my hallway that was previously wallpapered. After the past 2 days of heavy rain,this has appeared on the paint near the door window!

This could be a historical problem that I just didn't see before because of the wallpaper?

Anyway, on the outside the brickwork looks like this. The wall mark is just behind that slightly dogi coloured brick under the sign - is this likely to be the problem? The motar all seems ok when prodded...

Or maybe it's completely unrelated to the rain, bad plaster or something?

Absolutely no idea how to diagnose/fix this so really appreciate any advice!

Thanks!

 

[AHarvey]

I imagine it is a cavity wall so not sure if it would be possibile unless something was bridging the gap between them.

 

[Mark A]

Could it possibly be a water stain that is eating its way through the paint? Looks like new windows, so it could be that the original windows let water though at some time. Does it feel damp?

 

[ci_newman]

As has been mentioned, that will probably be a cavity wall so if it is damp, the water is getting in elsewhere (loose roof tile etc)

 

[BigJon]

Maybe try taking the sign off if it will come off. It doesn't look new enough to have a cavity wall, so water might be getting in under the sign, or the sign is stopping the brick drying out.