I'd found aileron, and thought it fitted the movable surface bit(as in airplane wing) but my dictionary didn't give the architectural definition.
Ok, this gives me _ C _ N _ _
Clue = Lean (6)
I'm thinking SCANTY but not sure if that's the same as lean.
it gives me _ N _ R _ _ _
Clue = Within or inward (7)
... Probably something starting with IN ?