We just repainted the wall and fixed the plaster last November due to water damage. Recently, I discovered that there appears to have some water damage on the wall again. This damage is right below a window. But the window has been closed the entire winter.
Can anyone help me to figure out what is the source of water damage?
I checked the exterior and couldn't find anything that needs repair including the tuck-point. Can it be condensation? The window curtain is also closed at all time which may make the condensation worse.
Below is the first time we had water damage last year.
2/2 Update: I took some photos as Jack recommends. I can see the paint on the exterior window sill needs to be repaired. But could that be the reason? We don't know much about whether if the window is original.But it's an old house and the window seems old.