
Which is safer/better - mounting the smoke detector on the exposed rafter, or on the plaster in between the rafters? From what I could make out online, there is potential for dead air between rafters, though these beams are quite as deep as some of the ones that were used in other examples.
Alternatively, what about mounting it on the wall? I've seen advice that suggests mounting it between 300mm and 500mm from the ceiling line, which would make it a little easier to silence in the event of a false alarm (especially for my wife, who is shorter than I am).