Attic Ventilation

Attic Ventilation
Proper roof ventilation keeps air circulating in your attic, and just like your body, good circulation is a key to good health. Give your roof the room it needs to breathe by ensuring that you have the proper amount of intake and exhaust venting for your roof. What is the proper amount? There are actually some industry formulas that will show you the answer, but don’t worry. You don’t have to get up in your attic or get on your roof. Just call Marathon Roof and we will come to your home to assess your roof’s ventilation. A properly ventilated roof has air that comes into it from the bottom, usually through soffit vents. That air blows through the attic and exits the roof through vents at the top or the sides of the roof, depending on your home. That flow of air takes heat and moisture out of your roof and leaves it with room to breathe.

During warmer months, ventilation helps keep attics cool. It helps prevent hot, moist summer air from warping the roof sheathing. It also stops shingles from deteriorating prematurely. What’s more, fresh air in the attic makes a home much easier to cool, which can result in lower energy costs. In winter months, ventilation helps reduce moisture to keep attics dry. It stops water from backing up under shingles, damaging insulation, and rotting the roof structure itself. Over time, these consistent problems brought about by both the warm and cooler months add up and take a significant toll on your roof. Unfortunately, you will be looking at purchasing a new roof much sooner than you had anticipated. The scariest fact of all is that 9 out of 10 homes in North America are NOT properly ventilated and experience early failure due to these problems.  Why? Because most people are unaware that attic ventilation can impact the longevity of their entire home!

The mission of our company is to provide long term customer service while utilizing a cutting-edge technology.  By using energy efficient products, we can reduce energy costs for homeowners and deliver a structully superior roof.  Ventilation is crucial to the life and effectiveness of every roofing system. Vapors and condensation can cripple R-values and encourage hidden decay in the building structure. Marathon Roofing’s certified personnel will create a system that performs where you see it, and where you can’t. For example, in the summer, an improperly ventilated attic can cause heat to build in excess of 160°F. This superheated air eventually penetrates the ceiling insulation into the living area below.

Some numbers:

  • Venting offers a significant 50 % reduction in the amount of heat penetrating the conditioned space versus deck-to-deck installations
  • 22% reduction in energy consumption

Types of damage that can result  from poor ventilation includes:

  • Premature aging of your roofing system (“fried” shingles)
  • Warping, cracking, or breaking down of wood framing
  • Damage to siding, exterior or interior paint, and wallpaper
  • Higher energy costs

A properly ventilated attic can help reduce the load on your air conditioner by moving the superheated air out of your attic before it builds up and causes damage. In the winter, various household appliances, bathtubs, showers, and cooking vapors can contribute to excess moisture build-up. Improperly ventilated attics will allow this moisture to collect and cling to the underside of the roof. There, it will condense and fall, soaking the attic insulation and reducing its efficiency

Additional structural damage can include:

  • Roof deck warping and rotting of the wood frame
  • Mildew growth
  • Buckling of shingles and felt
  • Proper Attic Ventilation

Proper attic ventilation systems allow a continuous flow of outside air through the attic (see illustration at right), protecting the efficiency of the insulation and helping to lower temperatures in the living space.

It consists of a balance between air intake (at your eaves or soffits) and air exhaust (at or near your roof ridge).

The FHA (Federal Housing Administration) recommends a minimum of at least 1 square foot of attic ventilation (both intake and exhaust) for every 300 square feet of attic space. For example, if your attic is 900 square feet, you need a total of 3 square feet of ventilation. This amount is generally divided equally between intake and exhaust ventilation (i.e., 11/2 feet of each), to insure proper air flow through the attic.



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