Roof Ventilation Theory

Controlling ice damming by keeping the roof cold.

Roof ventilation theory.

Exterior wind and interior stack effect building pressures tend to force warm interior air into the ventilation spaces exacerbating roof warming. The intent of roof venting varies depending on climate but it is the same if you re venting the entire attic or if you re venting only the roof deck. Roof ventiliation explained for australian homeowners by john breeze of northern rivers insulation. In a hot climate the primary purpose of ventilation is to expel solar heated hot air from the attic or roof to reduce the building s cooling load and to relieve the strain on air conditioning systems.

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. 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. Enhancing roofing material life span by reducing sheathing temperature. Removing moisture from roof cavities structural members sheathing and insulation.

Roof ventilation is one of the systems that performs best when air sealing has been properly completed.