Negative Pressure Roof System

Negative pressure is generated and maintained by a ventilation system that removes more air from the room than air is allowed into the room.

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. Air is allowed into the room through a gap under the door typically about one half inch high. Water moisture damage within the roof turns to vapor in low pressures created by the wind vent system. 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.

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. The negative pressure roofing system is referred to as a wind vented roof and is proven in thousands of roof installations. This makes our vacuum roofing ideal in harsh climates. 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. Water in this gaseous state can then exit the roof via the one way vortex valves.