One of the best ways to vent a flat roof is by specifying very deep roof trusses and providing vents at the perimeter of the shallow attic. Other methods include using open-web trusses to frame flat roofs or omitting air space above the roof insulation, but these are not recommended. Some roofers use one-way vents in order to remedy roof membrane blistering.Continue Reading
When using deep roof trusses and building vents at the perimeter of a shallow attic, make sure that the roof trusses are deep enough to provide for between 12 and 16 inches of insulation and an air gap of about 6 inches. Some roofers suggest framing the roof separately from the ceiling so that the resulting attic is deep enough for human access. When constructing vents at the perimeter of the shallow attic, choose freely between fascia vents, soffit vents and wall-mounted vents, making sure that the vents allow air from outside to connect with the air gap on top of the roof's insulation material.
Build one of several vented cupolas in the center of the roof to remain in compliance with most local building codes. In general, half of the ventilation area should be located in one or more of these cupolas.Learn more about Home Maintenance