When you own a home, one of the first things you learn is the importance of ventilation. If your bathroom isn’t properly vented, you’ll wage a never-ending war against mildew growth. If your kitchen ventilation system is inadequate, the smells from each night’s dinner will linger for days. And if your roof isn’t vented, you’ll face a host of problems, on both the inside and the outside of your house.
The good news is, ventilation problems around the house aren’t too difficult for an experienced contractor to make changes. Should the builder have ensured that the correct ventilation systems were in place from the very beginning? If you find that your home is warmer in the summer and chillier in the winter than you’d prefer, or if you’ve ventured into the attic in July only to be hit with a wall of staggeringly hot air, your roof may not be vented adequately (or at all).
How will you know if your roof needs ventilation? Not sure which ventilation system will work best for your house? Keep reading!
In spite of the emphasis on air sealing and insulation to increase your home’s energy efficiency, your house isn’t actually meant to be a hermetically sealed box. Airflow is important in a house, especially through the attic and roof.
Warm air rises, so if your attic isn’t properly insulated or vented, your home will be subject to the negative effects of trapped hot air throughout the year.
In the summer:
Heat builds up in the attic, overheating the roof decking and the ceilings in your home
Exterior roofing materials and shingles age more quickly due to prolonged heat exposure
Heat buildup in the attic transfers to the interior of the house, which forces the air conditioning system to work harder
In the winter:
Warm, moist air from the house seeps into the attic.
Condensation develops in the attic and on the roof’s interior structural elements, which can cause wood rot and deterioration as well as mold and mildew growth on attic insulation
Warm air causes snow on the roof to melt and refreeze at the eaves in the form of ice dams
An adequately vented roof and attic help extend the lifespan of two of the most expensive systems in your house: the HVAC system and the roof. It also helps maintain good indoor air quality, since stuffy, humid air is continuously moved through the house into the outdoors.
If you want a healthier, more efficient home, put roof ventilation on your home improvement priority list.
Signs of Inadequate Roof Ventilation
1. Ice dams in the winter
Ice dams occur when the snow melts on a roof, runs down the roof’s slope and freezes at the eaves. Water expands as it freezes, and these patches of ice can damage roofing materials and cause leaks. A poorly vented roof and the attic is warm at the top and cold at the bottom, which allows this melt/freeze cycle to continue.
2. Compressed or damp insulation
Insulation needs to stay fluffy and dry to do its job. When insulation gets wet, it compresses and loses some of its insulating ability. Wet or damp insulation is often a sign of condensation in the attic, which is a result of inadequate ventilation.
3. Water stains, mildew, or mold on wooden rafters, beams, and decking
Water (or even excess moisture) has no place in your attic. If you see signs of water damage on attic structural elements or the underside of your roof, your home likely needs better roof ventilation.
4. Frost on wooden rafters and beams
Frost in your attic or on the underside of your roof is a clear sign that moist air is getting trapped in your attic.
If your attic is accessible, taking a look around periodically is a good idea. Take note of anything that looks out of the ordinary, and call an experienced roofing contractor to investigate further.
The Bottom Line
An unvented (or poorly vented) roof and attic area is a ticking time bomb of sorts. Over time, moist, hot air trapped in the attic will cause serious problems, including mildew growth, structural deterioration, and degradation of important roofing materials.
Have your roof inspected by a professional every few years to catch small problems before they worsen, and always have any signs of moisture intrusion in the attic checked out. Installing or upgrading your roof ventilation system might not be the flashiest home improvement you can make, but the benefits for your home and its major systems are undeniable.