Narrow gauge station bulding

Chimney stack now done. The stack itself is a piece of square timber, wrapped in plasticard and topped with a bit of 60 thou and a length of plastic tube. The associated bit on the left (is this a breast back here?) is pure plasticard.
I have to admit that the design of this owes much to the Coopercraft platelayers hut; the slate capping is copied from the pub at the top of the road.
Now I have to work out a way to do gutters and down pipes. Umbrella ribs have been suggested, but I've not come across any yet.