subject: The Importance of Proper Roof Ventilation [print this page] The Importance of Proper Roof Ventilation
Having proper roofing ventilation is just as important as any vital component of your house. In order to provide proper attic ventilation, the number of attic vents need to be calculated and strategically installed in your roof. Proper functionality of your roofing system ventilation is critical, especially in cold climates. This is one of the most important issues associated with the attic area of your house. If you have an attic it is essential that it be accessible and periodically checked for any abnormalities.
The proper attic ventilation system allows a continuous flow of outside air through the attic of your home, thereby protecting the efficiency of the insulation and helping to lower temperatures in the living space as well. It consists of a balance between air intake and air exhaust.
Poor or improper attic ventilation can result in severe damage to many elements of your home. It will ruin the insulation, warp the roof decking and/or rot wood framing, destroy the shingles, and even cause the growth of dangerous mildew. Further, neglecting to ensure proper roof ventilation will raise your energy bills. It is estimated that 9 out of 10 homes in North America do not have proper attic ventilation!
The Federal Housing Administration recommends a minimum of at least 1 square foot of attic ventilation (both intake and exhaust) for every 300 square feet of attic space.
For example, if your attic is 900 square feet, you need a total of 3 square feet of ventilation. This amount is generally divided equally between intake and exhaust ventilation (i.e., 1-1/2 feet of each), to insure proper air flow through the attic. To calculate the amount of ventilation you need for your home, please refer to this Roofing Ventilation Calculator.
Often times when a roof becomes damaged many people strike it up to cheap materials or poor workmanship by the roofing contractor who installed the roof. While either of these reasons might be true, most damages to your roofing system are more often than not caused by inadequate roofing ventilation. In the winter, various household appliances, bathtubs, showers, and cooking vapors can contribute to excess moisture build-up. Improperly ventilated attics will allow this moisture to collect and cling to the underside of the roof. There, it will condense and fall, soaking the attic insulation and reducing its efficiency. Some of the most common types of damage attributable to inadequate roof ventilation include:
Premature aging of your roofing system ("fried" shingles)
Warping, cracking, or breaking down of wood framing
Roof deck warping and rotting of the wood frame
Mildew growth
Buckling of shingles and felt
Damage to siding, exterior or interior paint, and wallpaper
