Is It Necessary To Have Venting For Flat Roofs

Circulating the air in the attic has a number of beneficial effects on the roof and the house in general.

Is it necessary to have venting for flat roofs.

Air flow between vents will also be affected by the resistance to lateral flow. The aluminum base holds the vent in place with built in flashing. In other words the entire vent opening doesn t count as vented space. In this case ventilation is required and the roof can still become wet with condensation which may cause materials to decay.

Roofing does more than just cover a structure to keep things under it dry. That said air resistance and interference such as vent grates reduces the area of true ventilation. Roofs must also breathe in the sense that they must have adequate air flow to dry moisture to melt snow and to aerate structural materials. They work with multi layer and three layer roofing systems helping to reduce the build up of moisture.

The rubber boot conforms to the exact size and shape of the pipe to keep water from leaking in. Residential homes with flat roof vents make use of the boot vent. On most flat roofs however stack effect will be ruled out since all vent openings will be at approximately the same level and there will generally be only small pressure differences from wind. In summer attic ventilation does just the opposite.

Without proper ventilation roofs develop problems that can cause leaks into the interior of the house. Generally speaking you need a ratio of 1 300 where for every 300 square feet of ceiling space you need 1 square foot of attic ventilation. Klober breather vents can be installed in both cold and warm flat roofs if needed and their design enables them to ventilate between the layers. This is a basic venting system that simply acts as a base and holder for piping that is coming through the roof.

There are two types of flat roof. Cold roofs and warm roofs. In winter the circulation allows heat to escape thus keeping the roof colder and preventing ice dams from forming. Because porches are often open and unconditioned venting a porch roof for that reason is not usually necessary.

Your roofing contractor can provide the exact number of roof vents needed for your particular roof but the rule of thumb is one vent for every 300 square feet if there is a vapor barrier in the attic.