Quite simply proper attic ventilation’s is a balance of air intake and air exhaust through the attic. To get the proper amount of attic ventilation you need to determine the square footage of the attic space. You will also need to decided on the best ventilation device and understand what the NFA (net free area) is of the product or system in which you’re going to use.

Benefits of having proper attic ventilation:
• Prevent premature shingle failure and validate your shingle warrenty
• Maintain proper attic moisture levels which will prevent condensation and mold which in turn prevent wood rot.
• Prevents moisture build up to protect the R value in your insulation
• Prevent hot spots in the winter months which reduce ice damming in winter.
• Saves you money on air condtioning in the summer and heating costs in the winter.

Common mistakes we see are homeowners who call to add more venting thinking that adding additional vents will solve their ventilation problem. Another thing we see a lot is bathroom exhaust vents directly vented into the attic instead of through a wall or roof.
For many years attic ventilation has been calculated by splitting the venting into two areas, with 50% of the venting coming from the soffit or overhang, and the other 50% in your roof. Many experts now realize it is better to have 60% coming from the soffit venting and 40% percent in the roof. It is always important to ensure a balanced system of intake and exhaust. Adding more roof vents without intake vents can pull the air from the interior living space into your attic causing even more problems for your home. So call a professional who understands the principles of proper ventilation and how to install a balance system.
Net physical effects of Inadequate Attic ventilation to your roof.
Improper ventilation is a major concern for shingle manufacturers and is part of having a valid shingle warranty. On a 90 degree day an attic can reach up to 130 degrees causing the shingles to super heat and fail! Super heating of the shingles can cause the oils to dry out of the asphalt and the protective covering (the granules) will wear off exposing the asphalts. When the asphalts become exposed the UV rays will burn right through the shingle. This is very bad, as it will cause your entire roof system to prematureley fail.