Flat Roof Ventilation Requirements

It makes a difference with your venting requirements if you have a warm deck insulation between the roof deck and the membrane or a cold deck insulation below the roof deck.

Flat roof ventilation requirements.

It depends on where the insulation is installed. Hot roofs have the roof deck then insulation then the roofing material. Vent a cold deck dont vent a warm deck. The answer depends on the type of roof you have.

There are two types of flat roof. Duo pitch roofs greater than 20 0 pitch or greater than 10m span should have additional ventilation at the ridge to assist airflow through the roof void equivalent to at least a 3 mm wide continuous gap. How much ventilation does a flat roof need. In the instances where a warm flat roof has been laid ventilation isn t usually required.

Cold roofs and warm roofs. Prior to installing the ridge vent a 1 inch wide strip of roof decking is cut out along both sides of the ridgeline to allow for air movement through the vent. The glidevale technical team has co. R806 2 minimum vent area.

Openings in roof framing members shall conform to the requirements of section r802 7. A ridge vent is a ventilation strip that is placed along the ridgeline of the home. It is important that air movement occurs and is not impeded by any framing members of the. As opposed to old built up felt roofing with joins new single ply waterproof membranes are now most commonly used.

A cold roof or hot roof. Any type of roof from tpo to epdm can be either hot or cold. Required ventilation openings shall open directly to the outside air. To meet the requirements set out by the government for thermal insulation roof ventilation may be a requirement in order to achieve the desired certification for the property.

Attic ventilation shall not be required when determined not necessary by the code official due to atmospheric or climatic conditions. Additionally if the span is greater than 10m the overall ventilation area should be increased to at least 0 6 of the total roof area.