Flat Roof Ventilation Detail

Ventilation is vital to make this type of flat roof construction work.

Flat roof ventilation detail.

There are two types of flat roof systems warm and cold roofs which affect the positioning of the ventilation. Removal of excess heat and moisture will help the life of the roof and will help the functionality and efficiency of the hvac systems. 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. 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.

Unlike vented facades or pitched roofs flat roofs do not have sufficient height differential which is a driving fac tor for air movement within a cavity. Any type of roof from tpo to epdm can be either hot or cold. Alwitra flat roof details. Flat roof ventilation is achieved by creating air changes to the attic or plenum.

Since february 1997 active ventilation products avp has been a supplier of roof vents roof jacks and whole house fans for fema federal emergency management agency housing hud united states department of housing and urban development housing and for those in the modular commercial and residential markets. Flat roof ventilation allows for the circulation of air in the property particularly for warmer rooms in residential buildings. If there is not sufficient air exchange the construction is likely to fail. How much ventilation does a flat roof need.

This system is probably the most common arrangement for residential flat roofs. A cold roof or hot roof. Find all available details and drawings of vents for flat roofs in the format dxf pdf and dwg as downloads here. The disadvantage of this roof system is that the insulation is directly under the roof covering so the covering suffers considerable temperature fluctuations.

When thermal insulation is placed below the deck the ventilation must also be on the underside. Ventilation is crucial to these areas as they affect the building as a whole both inside and out. An approved sealant is then applied to the top of the membrane upstand before it is tied off with a jubilee clip. Hot roofs have the roof deck then insulation then the roofing material.

It depends on where the insulation is installed. Flat roof ventilation is beneficial to flat roofs in all climate zones no matter the color of the roof.