Roof venting allows fresh air into the attic space and lets older air cycle out. Soffit vents allow the fresh air in, which will travel up through the attic space as it warms and escape through the high venting. Without adequate and un-obstructed soffit venting to allow fresh air into the attic space, air becomes stagnant and heated which can lead to condensation (sometimes resulting in leaks), mould, damaged wood, and premature wear to the shingles. In the winter, a hot attic will cause snow to melt at higher points on the roof. Water will run down to the eaves and gutters, re-freeze and create ice dams. Ice dams will back up, often lifting the shingles, causing leaks and potential interior damage.
