With winter now receding and warmer weather on the way, many homeowners are contemplating home maintenance and repair issues such as roofing, energy costs, air conditioning and similar concerns.
Having an effective roof ventilation system is a key item that should never be overlooked, which raises the question: Do all roofs need to be vented?
The answer is that while some homes have little ventilation, others have none at all. Problems can arise from failure to ventilate attic spaces and crawl areas. Unwanted difficulties can include mold and mildew.
Proper ventilation can help keep your home cooler in the summer and warmer in the winter. In addition, good airflow and attic ventilation can help ensure a longer lifespan for your roof.
Roof vents, besides increasing airflow, also eliminate moisture allowing in cool, dry air, while expelling hot air and moist air.
Your local roofing contractor knows that for your home to stay healthy, it needs roof venting to breathe. In summer, for instance, your roof’s vent system helps cool the roof and underlying water barrier materials such as galvanized steel. This reduces the expansion of the metal and slows the aging of asphalt shingles.
Roof vents also are crucial in winter because they help prevent snow from melting, then refreezing in gutters, which can create ice dams that can cause leaks and water damage. These precautions can help homeowners avoid the premature expense of a new roof.
In most jurisdictions, building codes require that attics be vented, particularly in homes in which attic insulation is installed on the floor. The standard code formula requires 1 square foot of net free ventilation area for every 300 square feet of attic floor area.
These guidelines assume that half of the ventilation openings are in the lower half of an attic, generally in soffit vents. The other half are typically situated at or near the ridge. If a roof has no ridge vents and only soffit vents where the roof meets the siding, most jurisdictions require 1 square foot of net free ventilation area for every 150 square feet of attic floor area.
Soffits can be non-vented or vented to allow for maximum roof ventilation. These work best when a roof has narrow eaves, or if ventilation is needed for a large amount of attic space. Sometimes, cupolas, designed to ventilate and provide natural light, can also be used.
An obvious question might be what type of roof vent is best? Although many types are available, common types of roof venting primarily consist of two models: intake vents and exhaust vents, both of which are required to properly ventilate a roof.
A professional roofer can assess the specific needs of individual homes. But in general, intake vents allow cool air to enter an attic and help push out hot air, freshening the space and decreasing air temperature. Intake vents can be placed in one or more areas.
Exhaust vents, installed at the top of a roof, provide unobstructed opportunities for the escape of heat buildup, odors and moisture. Sub-categories include ridge vents, which are common in many modern homes. These consist of aluminum caps that span the peaks of rooflines. These tend to cover more than one area and can also be hidden by roof shingles.
Wind turbines, also known as “whirlybirds,” are among the oldest types of roof vents. A wind turbine consists of curved vanes configured in a circular shape. The vanes catch the wind and turn internal turbines that remove warm air and humidity.
Power vents, like whirlybirds, fit into holes in a roof. However, power vents have low-profile bowl shapes, and function with or without wind. Driven by electric fans, power vents are controlled by thermostats and typically used to upgrade older wind turbines. Some types of power vents are energy efficient and can be used in conjunction with solar panels. But hard-wired models that tie directly into the electrical grid of a home are more powerful.
Other options include box vents, which use wind to remove heat and moisture. Box vents are low profile and require no power. However, multiples of these are often needed to sufficiently aerate an attic.
Gable vents are specialized attic vents employed in homes with large gables. When used in concert with large gable attic fans, these maximize air venting.
The square footage of an attic space is important, because it determines the amount of venting needed to adequately remove humid, hot air.
A professional roofing contractor can be helpful to identify the appropriate ventilation system for your home.
For more information about venting or other roofing services, contact us!