Usually in line with the lower edges of the roof across the width of the gable wall.
Whats this all about then? A few cottages around the village with these shelves.
I shall get some pics if no one knows what i am on about.
We have one on our gable wall. It is supposed to shed a lot of rainwater. Mind you, our gable wall has quite a slope to it so the board does help. As you say, they are pretty common.
I'll post a photo shortly.
Thats the job right there. I had a feeling they were to shed rainfall but wasnt sure.
There is one in the village thats quite large on a two story (upper floor in the eves) cottage and i didnt think that much water would come from the top half of the roof, there seems to be more wall space below it than above it.
It is not unusual to find ledges of varying depth on timber framed cottages.
They usually follow the line of the internal tie beam where the lower and upper studs converge.
the reason why ledges are there ( sometime resting on oak angle brackets, 2-3 or more) is to stop the render cracking at this vulnerable and flexible point.
Sometime the rendering line protrudes above the ledge by about one inch or more in relation to the render below the ledge.
These are a later addition of course, sometimes they may also feature a lead strip for watersheding. Ledges only came into existence when homo sapiens decided to render these buildings.
We have a lovely one in the village here Middi, its on angle brackets and really looks like a large shelf. I shall get a photo of it the next time i am passing.