Improve roof longevity and energy efficiency through proper ventilation

By Metal Era. 

Discover why proper ventilation is crucial for maintaining roof longevity and energy efficiency in varying climates. 

Promoting a sustainable and energy efficient building can be accomplished with the right ventilation. This also prolongs the life of the roof system by reducing the difference between the outside temperature and attic air temperature. Metal-Era outlines the benefits of proper ventilation in supporting your sustainability needs. 

Benefits in warm regions 

In warm regions, during the dog days (and months!) of summer, proper ventilation on your building will help keep the roof cool, ultimately extending its lifespan. Keeping your roof cool is important, as excess heat can cause shingles to curl and deteriorate. 

Example (Fig. 1): Without proper ventilation, the left side of the attic is heating up to roughly 140 degrees, causing the roof sheathing to be 170 degrees. Meanwhile, the right side has a solid ventilation setup in place, resulting in the attic being roughly 25 degrees cooler while helping prevent premature shingle deterioration. 

Studies conducted by Oak Ridge National Laboratories found that ventilation can reduce the heat gain through the roof assembly up to 45% when compared to an unvented system. 

Benefits in cold regions 

In cold regions and/or during winter months, proper ventilation helps minimize the temperature differential between the attic and the outside air (Fig. 2), thus reducing the risk of moisture buildup that can cause rust and corrosion in metal roofs, insulation damage, and mold/mildew. 

One of the biggest benefits of proper ventilation is preventing freezing/thaw cycles that cause ice dams. There are three key elements to preventing ice dams: 

1 – Proper insulation: see the U.S. Department of Energy recommended R-values for each region. 

2 – Proper ventilation 

3 – Use of ice and water shields 

Proper insulation 

The U.S. Department of Energy has specific recommendations to properly insulate a building based on the climate, type of heating and cooling system, and the part of the building you plan to ventilate. 

Proper ventilation at-a-glance 

Proper ventilation minimizes the temperature differential between the attic and outside air. 

This prevents freeze/thaw cycles that cause ice dams by bringing in outside air at the eave and exhausting it at the ridge. 

Original article source: Metal-Era