Let’s first start with a couple of unbelievable stats about attic ventilation: 90% of current homes have the incorrect attic ventilation. Attics that are improperly vented can reach temperature exceeding 150 degrees and enough moisture can build up to cause large amounts of mold. WOW! In order to correct attic ventilation we need to know what it is. The definition of attic ventilation is: “The process of supplying continuous fresh air through the attic space”. In order to accomplish this, you need to bring fresh air into the attic (intake) and then move the hot moist air out (exhaust).
The goal is keep the attic space dry and at a temperature that matches the outside temperature as closely as possible. To do that, there are a few simple rules that must be followed.
1) The amount of vents needed is figured by a simple equation: For every 300 square feet of attic floor space a 1 square foot vent hole needs to be cut in the attic. Half of that hole goes on the roof and the other half goes in the soffit. For example, if a house has an attic floor space of 2,100 square feet. You divide 2,100 by 300 then by 2, which totals 3.5 12″ by 12″ holes in the roof and in soffit.
2) The vents need to be in balanced. The amount of roof vents (exhaust) and soffit vents (intake) need to be the same.
3) All the roof vents need to be at the same height on the roof. Putting roof vents at a different height will cause the upper roof vents to pull air from the lower roof vents. You don’t want that, you want the roof vents to pull air from the soffit vents.
4) Only install one type of roof vent on the roof. Do not mix box vents with ridge vents, turbines or power vents.
5) All of the roof vents need to be on the same side of the house. If you follow these rules you will have an attic ventilation system that is working at its optimal level.
For a professional evaluation by a licensed Omaha Roofing Contractor contact Roof-Tech at 402-896-5554 or check out our website http://www.arooftech.com