How a Roofing Ventilation System Works

Roofing Ventilation System

Each time that you take a breath, you inhale and you exhale. Your home may not have lungs, but it does need to breathe too, through an intake and an exhaust. The most important components of a roofing ventilation system, the intake and the exhaust work together to circulate fresh air into your home’s attic space and hot air out of it.

Why is a Roofing Ventilation System Important?

GAF Roofing Ventilation System

A well-designed roofing ventilation system provides continuous air flow.

In many modern homes, insulation, multi-paned windows and other materials keep out inclement weather and extreme temperatures. As a result, the flow of fresh air is restricted, and hot air can build up underneath the roof. Proper roofing ventilation eliminates the buildup of hot air in the attic space, which reduces energy costs associated with cooling. It also prevents premature roof failure from heat damage to shingles and underlayment. Without a proper roofing ventilation system, evaporated water from activities such as cooking, cleaning, and breathing build up inside your home, which can cause allergies, mold problems and damage from condensation. If your home is suffering from excessive humidity, condensation, or mold growth, you might have a house that needs its roofing ventilation system inspected.

Ventilation vs. Air Leakage

The unregulated and unintentional escape of air is air leakage. Drafts, rattling windows, and suddenly freezing rooms in winter are all examples of this. When warm air, and especially hot air, leaks out of your home through the roof in the wintertime, it can melt snow that refreezes overnight, causing ice dams to form. This loss of hot air also makes your heating systems have to work that much harder to reheat the home, which costs you money. Likewise, the loss of cool air from your cooling system and the buildup of hot air in your attic space in the summertime also increases your energy bill. Ventilation comes in two forms: direct ventilation, such as opening a window, and indirect ventilation, which is designed to allow air and humidity to flow while controlling temperature loss or gain. The largest form of indirect ventilation should be your roofing ventilation system.

How a Roofing Ventilation System Works

A roofing ventilation system works with both an intake and an exhaust to keep the attic as cool as possible in both the summer and winter. There are many different products that can be used to install the best ventilation system for each individual house. For most homes, a roofing ventilation system with air intake up through the eaves and exhaust out the ridge vent provides ideal air circulation. For certain types of roofs such as hip roofs, ridge vents do not provide enough square inches of exhaust and roof louvers must be used instead. This is why you need an experienced roofing contractor to assess your roof and recommend the best roofing ventilation system for your home.

To optimize a roof ventilation system, first measure the attic area, and calculate the square footage of the floor space. One of the common rules of installing a ventilation system is 3 x 100. For every 100 square feet of floor space, which would be a 10′ x 10’ area, you would use three square inches of intake and exhaust. Following this rule ensures that the roofing ventilation system has the proper amount of intake and exhaust. Otherwise there could be interruptions in the air flow and your home won’t receive enough air circulation.

Eaves and Soffit Vents

Ventilation along the eaves is usually installed with permeable ventilator strips beneath the eave, which allow humidity to pass through, or with tile vents set at regular intervals. Ideally, soffit vents that run the full length of the eave provide the best intake flow. At the very least, one ventilation set on either side of the attic can allow air to enter from one side and leave through the other, taking humidity and other environmental buildup with it. However, if you’ve got a crowded or cramped attic, it’s time to add a ridge vent.

Ridge Vent

Installing a continuous ventilation strip, or ridge vent, on the ridge of the attic and roof (the topmost joint of the triangle) allows hot, humid-laden air to leave through the roof. As the hot air exhausts, it draws in fresh air up through eaves, providing a continuous air flow. One of the added benefits of a ridge vent is that it blends in the with the roof line.

If you’ve been toying with the idea of getting attic vent fans in the summertime because your attic is BLAZING hot, or if you are concerned about the freezing attic temps in the winter, this podcast has more information about attic/roof ventilation.

If you think your home is short of breath, or want to make sure a new addition has proper ventilation, contact All Weather Tite. Our experts can provide a free estimate, explain proper roof ventilation and get to the bottom of any current ventilation issues your home may have.

Posted in Roofing Systems, Ventilation.

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