Understanding whether or not you need roof ventilation really begins with understanding the purpose behind roof ventilation.
The purpose of roof ventilation is to prevent heat buildup from occurring in the hotter months of summer and prevent moisture buildup in the winter. In some more extreme climates where snow and ice are a common issue, roof ventilation is necessary to prevent ice dams.
In the wintertime, cold air in the attic cannot hold water vapor in the air created by things like showering, cooking – even breathing – and that water vapor will condense in the colder air and turn into frost or drops of water. And that frost or water drops can get into the insulation and over time create all sorts of problems: Mold and mildew can form in the insulation; wood framing in the attic can rot; the overall air quality in the house can suffer.
In the summertime, heat buildup in the attic can damage shingles and it can make it harder for the air conditioning to cool the house (increasing cooling expenses). Without proper roof ventilation, summer bills can be higher than necessary, and long-term costs can be even worse.
To protect the home and lower expenses, homeowners should be certain that their home has ventilation adequate to ensure that attic spaces are not too hot in the summer and releasing too much moisture into the home in the winter.
For a roof ventilation to work properly, there has to be a good combination of intake vents and exhaust vents, otherwise the ventilation system won’t be balanced and will not be as effective. Proper ventilation is determined by the construction of the home. If the attic space is livable space, the roof deck will have to be ventilated, while the attic can be ventilated if the attic is non-livable space.
And sure, in the South, the bigger problem is heat buildup in the hot months, but only focusing on a ventilation system to protect against heat buildup could expose homeowners to cold-weather troubles.
The Federal Housing Administration recommends at least one square foot of ventilation for every 300 square feet of attic space. If your attic is too warm in the summer, it’s a good indication that you need more ventilation in your roof.