Having balanced attic ventilation is an integral part of roof maintenance.
When attic ventilation is balanced, the amount of intake ventilation is equal to, or exceeds, the amount of exhaust ventilation. The more intake ventilation, the better. An effective ventilation system removes heat from the attic in the summer and removes moisture in the winter. Here are six reasons why balanced attic ventilation is important.
1. Mold and mildew growth
A properly ventilated attic helps fight moisture buildup in the winter when warm, moist household air rises to the attic. A buildup of moisture can cause dry rot and mold or mildew growth. It can also lower the R-value of insulation, making it less effect. The R-value measures an insulating material’s resistance to conductive heat flow, or its thermal resistance.
2. Poor air quality
The buildup of moisture, and the mold that goes along with it, can lower the air quality in the rest of the household.
3. Ice dams
A balanced attic ventilation system keeps the roof deck more uniformly cool in the winter. This helps protect against ice dams which damage gutters and shingles and can stain interior walls. Ice dams are formed when the heat from the attic, combined with the heat from the sun, melt the show on top of the roof despite the fact that the temperatures outside are freezing. The melted show slides down the roof, then freezes again at the eaves and gutters.
4. Pre-mature shingle deterioration
In the summer, heat builds up in the attic. Without proper ventilation, this can lead to the de-lamination of roof sheathing and cause the shingles to loosen or break down.
5. Utility bills
Proper attic ventilation in the summer can also reduce the cost of utility bills. A cool attic lightens the load on air conditioners, refrigerators, fans, and other cooling appliances.
6. Roof warranties
Most building codes and shingle warranties require proper attic ventilation. In fact, for many shingle manufacturers, proper ventilation is required to validate the full terms of the warranty. If damage occurs to your roof because of improper ventilation, it might not be covered.