When it comes to roofing, many people think that the most important part is simply putting on the shingles and other accessories. However, what they don't realize is that proper ventilation is just as important when installing a new roof. Incorrect ventilation has been seen in Chicago, Mount Prospect, Yorkville and many other areas when dealing with older homes and not recently built homes. So any home that's over 10 years old may not have proper ventilation installed.
A hail damage inspection reveals too many vents on this roofing system. They have box vents (also called turtle vents), attic vent and a ridge vent.
The intake and exhaust of air in an attic must be equal for proper ventilation. According to the International Residential Code (IRC), the minimum requirement for this is 1/150 which means one net free area (NFA) per 150 square feet of attic space. This can be increased to 1/300 if needed, but 1/150 is preferable.
It's also important to make sure that there are enough soffit openings for proper intake. If not, then warm air will not be able to escape from the attic and your new roof won't last as long as it should.
When it comes to roof exhaust ventilation, you need to make sure that only one type of vent is used on the roof. For example, power attic vents should not be installed with box vents or ridge vents because depending on wind conditions, the secondary exhaust can act as an intake and not ventilate the whole attic correctly.
So when looking for a roofer, make sure they check all aspects of your roofing system - including ventilation - before giving you an estimate. Don't just go with whoever offers you the cheapest estimate because it might mean they're cutting corners and leaving out important parts like ventilation. With proper attic ventilation, your new roof can last its full lifetime!