Roof Vents For Flat Membrane Roofs

A tough reinforced double layer membrane system should not be affected by interstitial moisture.

Roof vents for flat membrane roofs.

Avp s flat roof vents are manufactured specifically for flat roof ventilation. Avp ensures that its roof vents and roof accessories install easily on membrane roofs and once installed can add years of life to a roof membrane. The keepa attic vent is typically used for ventilating attics and or plenums as a roof exhaust vent or as an air intake roof vent. In particular a warm roof system tends to be the ultimate protection from flat roof moisture concerns.

The keepa attic vent is built solely for flat roof ventilation a roof pitch that is 2 12 or less. Common flat roof membranes discussed in this article include built up asphalt tar and gravel modified bitumen and single ply membranes like epdm pvc tpo and kee. Attic vents relieve humidity during the winter and heat during the summer to help extend roof membrane life. What is flat roof ventilation.

Roof vents need to be built tall for flat roofs because flat roofs drain water poorly and slowly compared to steep sloped roofs. Made of corrosion resistant aluminum the keepa vent has a round concentric vent cap and standard 11 in. This is why the vertical height of the vents for flat roof ventilation needs to be at least 8 inches high. No ventilation is required with flat roofs when the right membrane is used and installed correctly.

Membrane roofing is often used on commercial flat roofs. Unvented flat roofs a technical discussion flat roofs have often been built with the insulation all on top of the vapor closed drainage plane as this avoids dew point condensation issues inboard of the roofing. Collar height square flange and an inner louver wildlife guard. An airspace is left above the ceiling insulation and below the under side of the roof decking and the roof is vented either around its perimeter with soffit vents a flat roof or the roof may be include intake venting at its lower edge through a soffit and outlet venting through a half ridge vent or similar outlet vent along the roof s uppermost edge a low sloped roof.

The short answer is. This slow drainage of water leads to ponding on the roof. There are two types of flat roof systems warm and cold roofs which affect the positioning of the ventilation. In addition such vents will relieve vapour pressure generated under a heated roof surface and this will help in relation to some types of membrane blistering.

Flat roof ventilation is a niche that active ventilation products avp has supported and supplied for many years. We also cover spray applied foam and liquid roofing options. All flat roof vents including air intake vents and air exhaust vents are used together for balanced roof top ventilation. However in many situations the insulation may need to be primarily or entirely below the flat roof membrane and between the roof joists if so what are the best options.

For insulating fills placed over cast in place structural concrete decks box vents are usually advisable to provide for drying of wet fill even if there is no vapour barrier.