During summer, proper attic ventilation seems like a no-brainer. On a hot day, an under-ventilated attic can turn into a broiling oven that radiates heat down through the ceiling into living spaces below, raising cooling costs and diminishing comfort. It may not be as self-evident, but attic ventilation is also important in winter, although for less obvious reasons.

Ice Dam Prevention

Ice dams form when the upper portion of the roof is warmer than the rest of the roof, causing snow near the peak to melt faster. This runoff re-freezes as it reaches the lower, frigid zone of the roof, forming a barrier that prevents water from draining into the gutters. Pooling water on the roof quickly penetrates the shingles and roof sheathing, dripping into the attic and eventually leaking through your ceiling. Serious water damage is the result.

Uneven roof warming is caused by accumulation of heat in the attic. Because warm air naturally rises, heat conducted from the living spaces up through the ceiling into the attic accumulates at the underside of the upper roof, warming only that section and causing uneven snow melt. The remedy is a uniformly cold attic. Make sure attic vents up at the roof peak and down near the soffits are fully open and unobstructed to permit optimum attic ventilation and exhaust accumulating heat.

Condensation Reduction

In addition to warm air, water vapor from the living spaces may migrate up into the attic through small cracks and gaps in the ceiling and around recessed light fixtures. Humidity accumulates in an under-ventilated attic. When temperatures plunge on a cold night, water vapor in humid air naturally condenses. Attic insulation becomes soaked by condensation, degrading its insulating properties and spawning mold growth. Wet wooden structural members in the attic may warp and rot. Maintaining adequate flow of passive attic ventilation into soffit vents and out the vents at the peak of the roof maintains constant circulation of air to exhaust water vapor and prevent condensation.

In greater Cincinnati, ask the professionals at Apollo Home Heating, Cooling and Plumbing for more options to ensure optimum attic ventilation.