Improved attic ventilation helps protect your roof and keep your home comfortable
In most homes, the attic is stuffed with insulation to help keep the home warm during the winter and cool during the summer. So it might seem counterintuitive to create openings in the space so it can be ventilated as well.
Yet proper ventilation is an important part of keeping your home comfortable in any season. Moreover, a poorly ventilated attic can cause a plethora of problems, such as faster roof deterioration and higher energy bills.
If there are no vents in the attic, any air in the space will have a more difficult time escaping. Family Handyman says the attic will trap warm, moist air rising from the living spaces below during the winter. During the summer, hot air will build up in an unventilated attic, which can conduct heat into the home.
This situation can quickly take a toll on the structural elements in the upper parts of the home. The International Association of Certified Home Inspectors says poor ventilation can lead to mold and mildew, wood rot, peeling paint, and even melting shingles. Pests such as termites and carpenter ants are also more likely to be attracted to the home when there are higher levels of heat and moisture.
Improper ventilation contributes to the winter phenomenon known as ice dams. Merle Henkenius, writing for This Old House, says ice dams form when warm air melts snow on the roof, with the water flowing down and refreezing on the eave. Ice dams can then trap water on the roof, causing leaks and structural damage.
Ideally, the attic should be cold in the winter, with the insulation working to contain heated air in the living spaces. The Energy Star program says a natural flow of air through the attic will prevent ice dams during freezing temperatures while removing moisture and extremely hot air from the space on hot days.
There are a few simple ways to check your attic ventilation to see if it is sufficient. Family Handyman says you should be able to spot some vents in the roof and eaves when inspecting these areas. The home may also have a ridge vent that runs along the length of the roof's peak or vents on top of the gables.
During the summer, check the ceilings beneath the attic to see if they feel hot. During colder months, you can inspect the rafters and other surfaces in the attic to see if moisture or frost are present.
A visual inspection can also locate some indicators of poor attic insulation. Schaefer Exteriors, a company based in Sykesville, Md., says these include gaps around pipes or ductwork, kitchen or bath fans that vent into the attic instead of through the roof, or vents located on only one side of the home.
The best way to ensure that attic insulation is adequate is to establish vents that will efficiently move air through the space. The International Association of Certified Home Inspectors says a combination of soffit vents to allow air into the attic on the underside of the eaves and ridge vents to allow air out will accomplish this goal; having just one or the other is insufficient. If eaves are not present, a "drip edge" vent on the edge of the roof can be used.
Many homes have passive ventilation, which relies on wind or a temperature differential to circulate air through the attic. Adding an active element, such as an attic fan, will get the air moving, particularly on stifling days with little wind. However, you'll want to make sure the attic is adequately sealed for this to work well. The Energy Star program says attic fans will pull cooled air up from the living spaces if the soffit vents are blocked or if there is not enough insulation.
Make sure any soffit vents are clear of obstructions. Henkenius says you should pull any insulation away from the vent and install a baffle to make sure the vent stays open.
Determine whether you have enough vents in the attic. Family Handyman suggests that there should be one square foot of ventilated openings for every 150 square feet of attic space, with these vents about evenly divided between roof and soffit vents.
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