Things have moved on a fair amount with this project now, and has reached this stage (I really should have filled in more progress as I’ve been going along!):
the vents on the end warehouse roof probably didn’t exist, but they do break up a large otherwise rather boring extent of plain roof!
however, I’ve come up with a dilemma (or more accurately a trilemma) of how to fill in the centre section of roof on the main building.
I’ve come up with three alternatives so far which I’ve mocked up:
this one I call the ‘barely legal’ option. A single ridge, but the slope either side is only about 22 degrees, which, reading around is borderline for the minimum slope allowed for a slate roof.
This one echoes the double peaked roofs of the boiler house and shed at the left end of the building (looking from the ground side). The pitch is a more sensible 40 degrees, and more aesthetically pleasing, matching the pitch of the gables either side. However what happens when it rains?
like the second option, the front and back pitches are a sensible 40 degrees, but the water trap in the middle is replaced by a flat roof - but is that realistic for a building built in the 1870s?
I’m not completely convinced with any of the options I’ve come up with so far.
The side and end elevations in the article I originally linked, and the few photos I’ve found don’t appear to show the centre rising higher than gables either side, so a single ridge with a steeper pitch doesn’t seem to be an option.