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Dispelling Myths About Roof Ventilation

Chances are, your home is of the 90 percent of U.S. homes that has way too much moisture. Excess moisture can damage your home and bring sickness to your family. Ventilation is important for keeping these issues at bay. But how do you know if your roof ventilation is doing its job?

There is some confusion surrounding the amount and types of roof ventilation you need to make your home habitable. We’re here to dispel the myths.

 

“You can never have too much ventilation.”

More doesn’t mean better when it comes to roof ventilation. Insufficient ventilation means excess moisture in the winter and humid summers. But too much means excess roof penetration and more opportunities for leaks.

So, how much is too much? And how little is too little? A professional is going to give you the right answer to this question. But a good rule of thumb is this: for every 300 square feet of ceiling space you need 1 square foot of ventilation. If your home obviously doesn’t meet this criterion, it’s time to call someone.

 

“Roof ventilation is only good for energy efficiency during the summer.”

Compared to shingle color, sun exposure, and insulation, roof ventilation doesn’t do much to increase energy efficiency in warm weather. Moisture damage caused by insufficient ventilation is actually more of a concern in the winter months. To prevent condensation on your roof sheathing in a colder climate, you’ll need adequate ventilation or highly rated, rigid insulation. Opt for the ventilation.

 

“Heat rises, so ventilating your roof system is just releasing all the warm air.”

If heat is escaping and heating bills are rising, it’s more likely that insulation is the culprit, not ventilation. Your furnace should not be heating your attic at all if it is properly insulated. If warm, moist air is being allowed to rise and hit your roof, the more likely it will lead to condensation and wood rot. If you take the temperature in your attic on a winter night, it should be similar to the outside temperature.

 

“My house came with roof vents, I’m sure that’s enough.”

Among roofing experts, there is little agreement on the best roof ventilation system—mostly because no roof or system is exactly the same. Ridge vents are an agreed upon effective and inexpensive solution for most roofs IF they have accompanying baffles. Gable vents only work on a small portion of your roof. Soffit vents may trap moist air against your roof.

To be safe, consult a roofing professional. The upfront cost of an inspection and installation could save you loads on repairs and illness in the future.