An attic with insufficient ventilation can be a source of problems year-round. During the summer, attic temperatures can soar to up to 150 degrees F., adding a heavy load to an air-conditioning system. In the winter, temperature differences between the attic and heated living spaces below cause moisture to condense on the underside of the roof, lowering the R-value of insulation, rotting rafters, sheathing and soffits, and causing ice dams to form near the eaves. Ice damming, buckled shingles, damp ceiling insulation and paint peeling off soffits are all signs that the attic needs better ventilation.

Most homes have a combination of passive vents, which include intake vents at or near the eaves and soffits, and outtake vents at gable ends or on the roof. The airflow pattern created helps equalize temperatures on both sides of the roof.

Creating and maintaining an adequate flow of fresh air through your attic depends on two factors: having a sufficient number of air intake and outtake vents; and making sure the air passages are clear.

INTAKE VENTS - Soffit vents can be added to increase intake airflow on closed soffit systems. Eave vents can also be installed in the house siding near the eave area. Gable vents are larger rectangular or triangular vents installed in the siding near the peak of a roof gable.

OUTTAKE VENTS - Flat roof vents are simple nylon, PVC or metal vent covers that fit over holes cut in to the roof, usually near the ridge. Ridge vents are highly effective, providing even outtake airflow along the entire ridge. Ridge vents are generally installed during initial construction, but can be added as a retrofit project or when reshingling the roof. Turbine vents are installed in much the same way as flat roof vents, but provide greater airflow by actively drawing air through the vent area as they spin. Even on a windless day, you will often see them slowly swirling, due to convection currents from hot air escaping the attic. You can also purchase powered turbine vents driven by an electric motor to establish a consistent airflow. Generally, you would install powered vents only in roofs with a significant airflow problem.

Questions or concerns about your roof ventilation system, email us at Palmer Custom Builders today, or call us at 704/841-4106.