Chimneys and Roofs – How They are SimilarApril 6th, 2016
What? Roof Systems and chimneys the SAME? You’re thinking, “No way, Jose!” Okay, before leaving this post, give me just a second to explain.
We at TRA Snow and Sun sell ventilated roof flashings and ridge risers which help with roof system ventilation. No, we don’t want you to set them on fire thereby showing that roofs and chimneys are the same because of fire.
Chimneys are ventilation systems for the hot air and smoke produced in a fireplace. Roof systems can also be ventilation systems. We’re not talking here about venting an attic, but venting UNDER the roofing product from eave to ridge.
In a chimney, hot air rises because it is less dense than the colder air outside the building. This causes a draft from low to high and out the top of the chimney.
For both chimneys and roof ventilation, there are factors which affect the amount of draft produced.
- The distance from eave to ridge on a roof or from the fireplace to outside in a chimney
- The temperature outside compared to inside for a chimney and from the eave to the ridge on a roof.
- Obstructions between eave and ridge. Design such as valleys, dormers, skylights, etc., will inhibit the venting of a roof system.
- On the roof, the lower the slope the harder it is for a draft to form, therefore the duct size or opening below the roofing product must be greater on lower slopes.
Venting a roof system in a cold climate will help stop ice damming and in a warm climate will cool the house by helping prevent radiant heat from the sun getting trapped by the roofing product.
Talk to the experts at TRA Snow and Sun about venting your roof!