Landing window on gable end wall leaks in at top seems only when we get wind and rain together had gable end pointed and water sealed still rains in above window
I was going to post similar Builder. I have come across water getting down the cavity to the window head when the underfelt has rotted and the eave tiles fall short of the gutter. But col said the window was in a gable end.
Another small question ........... I guess it's "face" brickwork (traditional.) So, do you have a brick arch over the window outside?
Maybe a "soldier" arch, which is bricks stood on end?
It could be curved or even a flat arch.
Most likely cause in a house of this period............
With a cavity wall .......... the outer "skin" is designed to saturate. It soon evaporates. The cavity prevents direct passage of water to the inner leaf (skin.)
Putting a window/door/opening across the cavity bridges it (quite normal.)
Water in the outer leaf will trickle down onto the top of the window .... hence ......... a leak.
To prevent this, a "cavity tray" is fitted across the window. This is stepped. The inner edge of the tray is built into the inner leaf roughly 9" above the window.
The outer edge of the tray sits directly over the window (more or less.) So the tray is stepped to make the aforementioned drips run downhill ... over the window ... and safely away to outside.
In those days, the tray would be made of tar-impregnated felt (like an old-fashioned damp-course.) This rots. 60 years would be enough time for this.
I've tried to make this as simple as possible for illustrative reasons. There may be an aesthetic consideration though. The window may well be set back a few inches from the brick face.
You'd have to consider how to deal with the obvious sight of a PVC tray looking at you .
There is a picture of a set of headers removed and a cavity tray being installed attached with this col. Not really a diy job. Unless you are proper handy.
Not a difficult job at all, but not for the faint-hearted. I've made a few assumptions, so it really needs to be looked at professionally, and quoted for.
A confident DIYer could easily undertake this, but it does need an experienced eye to assess any possible difficulties that might be met. I don't envisage any... but every case is slightly different.