Negative Pressure Roof System

Upward migration of water vapor is vacuumed out of the roof assembly through one way valves placed in wind vortex intensity areas of a building perimeter.

Negative pressure roof system.

Water in this gaseous state can then exit the roof via the one way vortex valves. Such a negative pressure roof system would have to be able to accommodate these positive interior pressures as well as the negative ones imposed on the top surface of the roof membrane. No fasteners need to be used on the roof surface so the vapour control layer is not punctured. Except for this gap the room should be as airtight as possible allowing no air in through cracks and gaps such as those around windows light fixtures and.

Negative pressure is generated and maintained by a ventilation system that removes more air from the room than air is allowed into the room. When the vacuum roof is exposed to wind forces negative pressure is generated in the layer between the membrane and an airtight load bearing substrate. Continuous self drying of wet roofs with wind vented negative pressure system. Air is allowed into the room through a gap under the door typically about one half inch high.

Some storm conditions actually cause the building interior to become pressurized such as when fenestration fails loading dock doors are open etc. The membrane is laid in 2 or 4 metre widths then air sealed against the parapet and around any penetrations.