This Old House - Improving Attic Ventilation

This Old House - Improving Attic Ventilation
By: Merle Henkenius (Page 1 of 2)

For most of us, the attic is a place to store clothes, luggage and old family photos, but for energy researchers it's a hot topic of discussion. In the last several decades, building codes have called for increased attic insulation. Most experts contend that a well-ventilated attic keeps the house more comfortable in summer and guards against moist, heated air building up in winter. There are also dissenting voices who say that the benefits of ventilation are overrated.

Who's right? Obviously more research is needed, but here's what we do know:
• Don't avoid ventilating your attic for fear you're letting cold air into the house. Your actual living space is sealed and insulated at the attic floor—the attic is outside this envelope.
• If there are asphalt shingles on your roof, the attic must be ventilated to comply with the terms of the manufacturer's warranty.
• One reason for the lack of agreement over attic ventilation is the tremendous variation in climate across North America. Rarely will you find a building practice that works everywhere.

For instance, attic ventilation is used widely in cold climates to evacuate the warm, moist air that escapes from the living space below. If this air lingers, it can condense on the underside of the roof sheathing and rot it. A healthy airflow also helps with ice dams, which begin to form when warm air in the attic melts the snow from beneath and creates runoff

This Old House Television
135 West 50th St, 10th floor
New York, NY 10020
Phone: 212-522-9465
Fax: 212-522-9435
E-mail: contact@thisoldhouse.com