A Simple Guide to Understanding Attic Ventilation

Few people realize how important attic ventilation actually is. This particular factor affects the structural integrity and durability of theroof. Note that insufficient ventilation can void the manufacturer’s warranty for some types of roofing, so should it fail, you will have to spend a lot of money on replacement and repairs.

To avoid the problems caused by poor airflow under the roof, you’ll need to provide your attic with a suitable ventilation system. The options you can choose from include:

  • Ridge vent - this is the vent installed at the peak, or ridgeline, of the roof that allows the hot air in the attic to escape through an opening approximately 5" wide that runs the length of the vent. To install this vent, ¾ of an inch of roof decking needs to be cut along both sides of the ridgeline. Vent-a-ridge is not used with any other ventilation and is the most affective in ventilation because while vent-a-ridge expels hot air from the attic the soffit vents serve as the intake of cool air. In order to be a candidate for vent-a-ridge your roof needs to have enough gabled area based on the square footage of your roof and there must be soffit vents in place. There is an industry calculation used to determine how much VR is needed on your home so that the intake and exhaust balance.
  • Soffit Vents - the soffit areas of your house must have vents in order to provide convective movement of air in the attic. These are intake vents. kThe air would move from soffits to ridge vents. Many newer homes are equipped with soffit vents. Note that both soffit and ridge vents are necessary to provide most efficient attic ventilation.
  • Mushroom roof vents - mushrooms are passive, meaning they work without electricity. They are 15” in size
  • Airhawk roof vents - a 7” passive ventilator with a round hole, these should be installed evenly across the roof line, generally closer to the top of the roof. To be affective most roofs need several of these to cool the attic.
  • Turbine roof vents - turbines are mushroom-shaped vents that spin with the wind currents and help to expel hot air from your attic. They do not require electricity so they are also passive.
  • Solar power fan - solar power fans do not use electricity so it is free to use. The fan only works when it is getting direct sunlight, so if it is cloudy the fan will stop. Make sure to install it in a spot that does not have any tree coverage.

There are also other types of vent systems that can be installed depending on the home construction and some other factors. It’s essential to consult an experienced roofer in order to choose the option that would work best in your particular case. It might be difficult to understand all the ‘ins and outs’ of correct attic ventilation, so it’s always best to have a professional do this for you. Remember, providing a good airflow in the attic saves you money and stress by reducing the speed of roofing deterioration.

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