By Andy Swan, Roof Saver.
By now you know that attic ventilation is a means to allow hot, moist air to escape from the attic. The excess heat needs to escape for the comfort of the occupants, to reduce air conditioning demand and to get as much life from the roofing covering materials as possible. You want the moist air to exhaust from the attic primarily to deter the growth of mold and mildew but also because too much moisture in the attic reduces the effectiveness of attic insulation.
An effective attic ventilation system requires a balance of intake and exhaust vents. The use of vented soffit as an intake and continuous ridge vent as exhaust is a popular way to achieve the requirements of the building code. The building code offers two ratios depending on construction materials. If the warm in winter side of the attic has a vapor retarder such as Kraft faced insulation you can install one square foot of net free area per 300 square feet of attic area. If the attic lacks a vapor retarder you need twice the total net free area of attic ventilation and use the 1:150 ratio.
If you remember your school days, checking your work was a best practice. The same is true for the roofing materials you use – who’s checking their work? We do have a complete study guide to help you become a ventilation expert - click here.
Andy Swan is president of Blocksom and Co., manufacturer of Roof Saver Ridge Vent. For more information on Roof Saver visit www.roofsaver.com.
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