Roof Ventilation Theory

Theory behind venting ice dams form when a home s escaping heat warms the roof sheathing and melts the underside of the snow layer on the roof.

Roof ventilation theory.

Roof ventiliation explained for australian homeowners by john breeze of northern rivers insulation. In mixed climates ventilation serves either role depending on the season. A passive roof ventilation system which has openings low and high is designed to move air in an unconditioned space using the natural flow of air called stack effect. Enhancing roofing material life span by reducing sheathing temperature.

Controlling ice damming by keeping the roof cold. Removing moisture from roof cavities structural members sheathing and insulation. Exterior wind and interior stack effect building pressures tend to force warm interior air into the ventilation spaces exacerbating roof warming. Roof and attic ventilation provisions can actually promote roof warming if they are open to the interior conditioned space s.

There are traditionally four main reasons for venting a roof.