What Are The Signs That Your Roof Isn’t Properly Vented?

When hot air from your attic isn’t sufficiently ventilated, your roof can become damaged, leading to expensive repairs. Many people don’t understand the importance of attic ventilation and how much damage improper ventilation can cause to roofing materials. When attic temperatures rise to 150 degrees or higher in the summer, it can lead to damaged shingles, a buildup of condensation, and unhealthy mold and mildew growth. 

When your attic is improperly ventilated, the second floor of your home can be up to ten degrees hotter than the first floor. Poor ventilation problems have significant consequences that can cost you time and money. They cause an increase in your overall energy costs and create significant damage both inside and outside your home. 

We want to help so this doesn’t happen to you! In this blog post, we will tell you eight signs that indicate you don’t have proper roof ventilation. 

Damage to Shingles and Roofing Materials

Too much moisture in your attic can cause a lot of damage to your roof. Rust may form on your roof nails and venting duct straps. Unsightly mold, algae, or fungus may appear on your roofing materials. Your roof can decay because of moisture in your attic. 

Uncomfortable Indoor Temperatures

When poor ventilation causes hot air to build up in your attic, it can flow into your living space, making your home uncomfortably warm. When hot air builds up in your attic during the summer, its temperature can climb to over 150 degrees. The hot air then passes through your attic floor into your home. This results in increased energy bills, an overworked air conditioning system, and an uncomfortable indoor atmosphere in your home. 

Dampness in Your Attic

When roof ventilation doesn’t work correctly, moisture from rising warm air condenses on your rafters. Dampness in your attic is a clear sign you have problems with the roof ventilation. 

Ice Dams

Attic ventilation systems should bring attic temperatures as close to outdoor air temperatures. In the wintertime, cool air enters the attic through intake vents above the eaves and helps prevent ice damming. Ice dams develop when snow melts and then refreezes at the edges of your roof. This refreezing is because of the buildup of heat in your attic space. 

Ice dams can cause extensive damage. They may cause damage to your walls, ceiling, and insulation.  

Moisture Build-Up

During cold winters,  excessive moisture can build up under your roof due to poor insulation. When too much moisture is trapped in your home, it can cause your paint to peel or blister. This can happen with both indoor and outdoor paint. 

Flashing on Your Roof is Visible

Roof flashing is a thin material, usually galvanized steel, that professional roofers will use to direct water away from critical areas of the roof, wherever the roof pane meets a vertical surface like a wall or a dormer. Flashing is installed to surround roof features, such as vents, chimneys, and skylights. 

If you can see the flashing on your roof, you may need to call a professional to replace it.

Roof Warp

Roofs with poor ventilation will often warp, creating a texture of lumps and bumps visible to the naked eye. Improper ventilation will cause the plywood beneath your roof to delaminate and curl. Excessive heat stored in the house can also melt the glue of the roof sheathing, creating a slightly buckled appearance. If you’re looking at your roof and notice hips and dips, it’s the first sign something may be awry. 

Mold on Attic Sheathing

Mold growth on attic/roof sheathing is common in cool climates, such as the Pacific Northwest. In the vast majority of cases, mold growth is caused by condensation. This occurs when the sheathing temperature drops below the dew point, creating a thin layer of moisture. If this happens regularly, mold spores will activate and begin to grow. 

Mold growth will return if the underlying issues are not addressed. Typically, this involves increasing the roof ventilation and air-sealing the top floor’s ceiling. Combining these two techniques limits the influx of warm, moist air and helps remove the damp air that slips through. 


If you notice any signs of improper roof ventilation, fill out the form below to contact us for a free inspection.