When assessing the state of the roof, an often overlooked issue is poor ventilation. In fact, some homeowners may even close off ventilation in areas like the soffits because of the mistaken belief that the vents are compromising heating or cooling costs. The following are a few issues that insufficient roof ventilation can lead to.
Roof Moisture Damage
The most alarming sign of poor ventilation is damaged shingles. Excess moisture trapped inside the attic may seep through the seams in the roof decking, leading to moisture beneath the shingles. Further, the roof may take longer to dry after rain or other moist conditions because of a lack of airflow beneath the shingles.
Curled and cupped shingles are often one of the most major signs of damage, but you may also notice shingle cracking and granule loss. Paint may blister and peel from soffit and fascia boards. There may even be increased moss and algae growth on the roof due to the moist conditions.
Ice Dams and Icicles
Poor ventilation is almost always at the root of ice dam problems. In a properly working system, cool air enters under the roofing through soffit vents. This cool air forces rising hot air further up so that it vents from the roof ridge and gable vents. If this doesn't occur, the hot air from inside the home is trapped in the attic where it causes premature melting of ice and snow on the roof.
It's this melt that causes issues. The melt water typically makes it to the edge of the roof and then the cold exterior air refreezes it, resulting in an ice dam and water backflow beneath the shingles. It's the backflow that causes leaks. Further, large, dangerous icicles may also form along the roofline due to the quick melt on the roof but cool air temperatures.
Damp Attic Issues
Moisture in the attic may not mean that you have a leak. In many cases, the moisture is caused from poor ventilation. Warm, moist air from the house rises upward. If it can't vent out, then condensation will collect on the rafters and the underside of the roof decking.
Sometimes the moisture is only enough to dampen rafters and cause some mold growth. In extreme cases, the moisture will drip back down onto the insulation and anything else that is on the attic floor. This moisture drip can lead to extensive water damage.
Fortunately, a roofer can assess your rooftop ventilation and make any necessary changes to ensure you don't have any of these issues.
To learn more, contact a roofing service in your area.