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  • Writer's pictureShannon George

Venting Is Key

In a previous post, we discussed ways to ensure your roofing system is properly ventilated. In this article, we explore and explain the issues and consequences when a roofing system is not properly ventilated.

First, what is a ventilation system?

The roof ventilation system allows air to move through the attic and is necessary for all homes. The moving air flows and will escape through roof vents. Roof vents allow the flowing air to escape. This is important because the vents move moisture away from the home and excess heat out as well.

Just as important as a ventilation system is that it is installed properly. When correctly installed, it will keep moisture from building up in the attic space as well as prevent overheating in the attic. Build up of moisture leads to condensation which can lead to health concerns and an abundance of heat buildup can weaken the integrity of the home's structure.

Poor ventilation whether from no system or an improperly installed system lead to numerous problems. Owning a home is an investment and making choices that extend the longevity of that home such as a properly installed ventilation system will help to keep a proper return on the investment of home ownership.

What Happens Without Proper Roof Ventilation?

The absence of ventilation in the attic or improper ventilation can cause the roof materials to deteriorate over time which in turn will compromise the structural integrity of a home. Condensation, thermal shock, heat buildup, and rusting are all things that can damage the roof and home. With poor ventilation damage to the roof will happen. Causes of damage may include condensation, rusting, and thermal shock, rusting.


In cold climates, roof vents ensure that the attic is at the right temperature. When it is icy, roof vents will prevent ice dams from forming. Ice dams develop over a short period when the heat of the sun and the warmth of the roof melt the snow and ice. This water then collects, refreezes, and creates puddles along the roof. Also, ventilation will allow any moisture in the air to clear from the living space below, escaping through the attic.


As a result of poor ventilation, rusting can occur and will lead to roof rot. A roof is made of up metal materials that hold it together. The metal connects shingles to the decking and underlayment. Without ventilation, the metal will rust. Rusted metal is weak and will no longer hold the parts of the roof together. In a worst-case scenario, this will lead to a full roof replacement

Thermal Shock:

When hot air doesn't move through the attic and out through the vents, heat from the sun enters and does not have a way out. The temperature in the house will go up, and the cooling system of your home will have to work overtime to cool the home. Thermal shock can speed up the wear and tear of the shingles of your roof. Since are the first line of defense in protecting the home, thermal shock can lead to more costly repairs than just shingles.

Poor roof ventilation can impair the health of those living in the home.

A final caution that can come from improper roof ventilation.

Seasons in North Carolina typically give us mild winters but humid and hot summers. If hot air isn’t able to flow and escape out of the roof this leads to a buildup of condensation in the attic. The trapped moisture turns to droplets of water collecting and running down the internal structures or the ceiling. The excess buildup of moisture creates a breeding ground for mold. Mold within the walls of a home can significantly impact the health of those living in the home. As molds grow and produce spores that float in the air, allergens are produced. Touching and/or inhaling mold and mold spores has been connected to allergic reactions that can include red, itchy eyes, a cough, sore throat, rashes, wheezing, and uptake in full asthma attacks for those with asthma. Some studies have also indicated that mold in the home can be a contributing factor to developing asthma in children under the age of seven. In more extreme situations, allergic reactions to mold can lead to hypersensitivity pneumonitis and the symptoms are more extreme than a typical allergic reaction.

Some signs of poor ventilation:

  • North Carolina typically has what is considered mild winters. However, North Carolina can have its share of winter weather. When it snows, this can be a telltale sign if your roof has poor ventilation. With proper ventilation, a blanket of snow will remain on the roof because the air is properly circulating and matching the air of the attic is close in temperature to the air outside. However, if there is snow and there is not a blanket of snow on the roof, it is a good indication that the roof has improper ventilation. This will be due to the roof being warmer than it should. If you see signs of this, it is time to call in the roofing experts at Herring to assess your roof with a full inspection.

  • Heat buildup that leads to condensation will also show signs of poor ventilation. Warped wood is a result of condensation due to poor roof ventilation. If the roof appears to look different or take a different shape, this is also an indicator of poor ventilation in the roofing system.

Herring Residential and Commercial are the experts in North Carolina and can ensure that your ventilation system is properly installed to protect the integrity of your roof. If your system is already showing signs of structural damage, the experts at Herring will install a new full roof replacement with quality service at a fair price. Schedule your appointment with our experts for a free estimate.


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