Q. How should a "diamond" hip roof (one with four hip rafters rising to a point) be ventilated?

A.I would recommend continuous soffit vent on all four sides, and hooded roof vents near the peak on three slopes. The front-facing slope usually does not have a vent, for appearance. If there’s a cathedral ceiling interior, holes can be drilled through the hip rafters to access the three other vents, provided you don’t compromise the strength of the rafters. While this arrangement does not provide equal high and low venting, it is about the best that can be done. The stack effect, created by having all of the vents in one area, is usually enough to move sufficient air. It is essential that there be an air barrier and vapor retarder in the ceiling, and that all exhaust fans be vented through the roof or out the walls, to minimize the attic moisture problem.