of attic areas and the roofing system is not only lawfully necessary, it will increase the longevity of the roof itself. Ventilation is the circulation of air in and out of the attic or area lying just underneath the roof. Improper ventilation can and will lead to problems both in the summer and winter seasons.
Ventilation In Summer
In the summer months, the sun can cause the heat to dramatically increase in the attic space. In a building with poor ventilation, the temperature can be 50 degrees higher than the outside temperature. The trapped air contains moisture and this can accumulate in the roof decking, shingles, and support structures underneath resulting in distortion and early deterioration. This heat will also radiate downwards into the living areas which will cause your air conditioning and other appliances to work harder, giving you a higher energy bill.
Ventilation In Winter
During the winter, warm air from the living areas will rise into the attic area from electrical and plumbing bypasses as well as through the ceiling. This warm air condenses on all the cold surfaces here and this time the accumulation of excess water can create a few different problems.
One, the condensed moisture on the structural surfaces will cause the deck to swell which causes the deck and shingles to buckle. Two, while doing this, the wood will rot from the condensation and lose its ability to hold fasteners or support any weight. Three, the condensation will also drip onto the insulation above the ceiling, rendering it ineffective and allowing the water to seep into the ceiling. This wet insulation causes mold, mildew, and promotes wood rot. The fourth is the formation of ice dams during snow fall, resulting in ice damage to all areas of the roof, outside and in.