We all know that stable ambient temperature is what keeps us comfortable indoors. This is why we consider insulation such an important investment. Our HVAC heats or cools the air inside our homes, and we want to make the most of it. It makes perfect sense from both a comfort and an energy standpoint. But what few homeowners recognize is the importance of allowing air to flow freely through the home and out of the roof. It seems counterintuitive to let all that precious air escape, but without good roof ventilation, your home (and pocket) will soon suffer. The following graphic illustrates what roof ventilation can do for your roof and living spaces in the summer and winter months. In fact, the US Department of Energy goes so far to say that roof ventilation is the single most cost-effective way to keep your home cool during the warmer months, allowing you to enjoy maximum comfort and energy savings to boot. And as time goes by, good ventilation only builds on these advantages. The Dangers of Poor Ventilation A well-ventilated roof is a long-lasting roof. The inverse is also true. Below are some of the common issues associated with nonexistent or improper roof and attic ventilation: ● Mold and mildew. Ventilation provides a conduit through which warm, moist air can escape. Without it, your attic becomes humid, which leads to the growth of mold and mildew. ● Weak decking. Moisture can seep into your roof’s underlayment and weaken the adhesives that hold your roofing material in place. ● Premature roof deterioration. Granular loss, cracked shingles, and other signs of deterioration often result when heat and moisture are trapped under your roof. ● Ice dams. Ice dams form when warm air in your attic melts the snow on your roof, creating runoff. As the temperature drops, this melted snow refreezes. Repeated cycles of melting and refreezing result in ice dams that trap water at your eaves and cause massive amounts of damage. Types of Roof Ventilation There are several different types of roof ventilation ranging from basic static vents to more complex motorized units (power vents). Some of the most popular types include: ● Ridge vents. Ridge vents provide the most efficient exhaust ventilation. They are installed along the roof’s ridges and often run the entire length of the ridge. ● Soffit vents. Soffit vents facilitate intake ventilation. They are installed along the eaves or the underside of the roof’s overhang. ● Gable vents. Installed at the gables, these vents often come with a fan to improve their performance. ● Roof vents. These vents could take the place of ridge or gable vents for exhaust, provided they are placed higher up. They are installed right on the surface of the roof. Installation Considerations While having ventilation is a step in the right direction, it is not an end in itself. Ventilation has to be properly installed for it to be effective. The US Federal Housing Administration and the International Residential Code for One and Two-Family Dwellings recommend: ● 1 foot of both intake and exhaust ventilation for every 300 square feet, if half of the vent openings are along the soffits, and the other half are along the ridges. ● 1 foot of net-free ventilation for every 150 square feet of attic floor space, if there are only soffit vents. ● At least an inch (25 mm) of space between the insulation, the roof sheathing, and the soffit vents. Local building codes also have specific provisions regarding ventilation, especially in certain climate zones. Your best move would be to consult a licensed contractor to make sure that your roof and attic ventilation complies with all the necessary regulations. Author Bio: Jon Wright is professional roofer based in Texas and the owner of Jon Wright Industries. He is very passionate about what he does and loves to share his experiences to other people. Read more about him by liking his Facebook page.
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