Inadequate Roof Ventilation - Problems and Solutions

July 27th, 2011

One of the keys to the performance of a commercial roof is for the roof system to maintain constant temperature. Buildings in extreme weather conditions will of course experience heat and cold based on the outdoor environment. The question is, how much will those temperatures fluctuate? If there are large swings in temperature over short periods of time, this can cause problems in a roof system.

One of the most important factors to ensure constant temperature in a roof system is adequate ventilation. When roof ventilation is balanced, i.e. the air intake is equal to the air exhaust, the life of the roof itself is prolonged and the environment protected by the roof system is more easily optimized. When the roof doesn’t have proper ventilation any number of problems can result.

Mold and Mildew

In very humid climates one of the most common problems which can occur underneath the roof deck is mold and mildew. When excess moisture builds up, mold damage can begin to take its toll in just a few days. Once it starts to run its course it’s often difficult and costly to get rid of. One of the best ways to prevent mold from setting in is to maintain proper airflow within the roof system; especially in a steep slope roof.

Ice and Snow

Ice build-up is another problem frequently seen when a roof has unbalanced ventilation. Buildings in areas with colder temperatures (30 degrees or less on average within a 30 day period) are susceptible to snow and ice build up around the eaves because air is not moving past them in correct volumes or not moving past them at all. When there’s proper ventilation the regular air movement prevents the build up of ice and snow.

Shingle Damage

Shingle failure is another result of improper ventilation. In extreme heat shingles can buckle, blister, peel or cup. Their lifespan is shortened when they’re allowed to bake in excessive temperatures. While it’s important to use the correct commercial grade roofing products to cover the roof deck, the ventilation system at work below remains a critical factor in the life and performance of those materials.

Engineered Ventilation

Atlas Roofing® Corporation now offers the most complete roof ventilation system specifically designed to achieve balanced ventilation and eliminate problems caused by lack of airflow beneath the roof deck. Techni-Flo™ is an engineered ventilation system manufactured for use in steep-slope roof applications. It can be used with shingle or standing seam roofs.

Techni-Flo combines a nailable polyiso insulation product with eave and ridge vents engineered to spec for each individual roof; so each provides a prescribed ventilation capacity.

Polyiso insulation provides the most R-value per square inch available in the building industry. When used in the Techni-Flo system as sheet insulation and vent spacer strips polyiso controls temperature and facilitates cross-ventilation.

The Techni-Flo system creates intake airflow using eave vents specifically engineered for prescribed roofing requirements. The exhaust air flows out of the system through a ridge vent also manufactured to spec, so the air volume moving through the polyiso insulation panels remains consistent and even. When airflow in commercial roofing systems is balanced, temperatures remain constant and life of the structure is prolonged.