Why Is Proper Roof Ventilation Important?
Proper roof ventilation is important year-round. During the summer months, proper ventilation keeps attic temperatures low and below 150 degrees. During the winter months, a properly ventilated attic will remain cold; therefore, snow will not melt and run off the roof to create ice dams. A homeowner’s roof can be damaged prematurely, along with moisture issues, if there is no proper ventilation.
For proper roof ventilation, there must be at least 1 square foot of vent space for every 300 square feet of attic space. There must be equal amounts of intake vents (soffit) and exhaust vents (ridge). When there is an imbalance of intake to exhaust, there is potential for damage to your roof.
Common Roof Ventilation Issues with Massachusetts Homeowners
Too Many Intake Vents, Not Enough Exhaust Vents:
Many Massachusetts homes were built long ago, which have numerous soffit vents, but do not have enough ridge vents. This type of configuration creates a dead area above the ceiling where there is no exit path for hot air. As a result, the air remains heated; therefore, the shingles curl, crack, and deteriorate years before their time.
Blocked or Insufficient Ridge Vents:
Massachusetts homeowners who have ridge vents installed on their homes, there is still have the potential for these ridge vents to be blocked by insulation in areas above the ceiling. Similarly, some ridge vents are either too small or incorrectly installed.
Bathroom and Dryer Vents Located in the Attic:
One of the most common roofing problems we find is improper ventilation of bathroom fans and dryer vents. Local building codes dictate that bathroom fans and dryer vents must exhaust outside and cannot exhaust inside the attic. If improperly vented, thousands of gallons of moisture enter the attic space each day, leading to mold, wood rot, and rusty fasteners.
How Does Poor Ventilation Damage Your Roof Over Time?
Heat damage to shingles occurs when the hot air becomes trapped and makes the asphalt shingles brittle, causing them to contract and develop cracks. Due to poor ventilation, a roof that was designed to last 20 years typically lasts between 8 and 10 years.
Moisture accumulation occurs when humid air enters the attic space and condenses on the rafters and sheathing. At this point, wood begins to rot, the sheathing starts to delaminate, and mold begins to spread. The insulation in the attic also loses its efficiency and drives up energy consumption.
The rate of ice dam formation is directly related to the temperature of the attic space. When the attic is warmer than the rest of the roof surface, it causes the lower portion of the roof’s snow to melt. The melted water then runs to the colder roof eaves and refreeze forming ice dams. Once ice dams form, the weight of the ice dams forces water underneath the shingles and causes roof leaks.
Signs of Poor Ventilation in Your Home
Asymmetrical snowmelt on your roof indicates a problem. If the snow on your roof melts unevenly and the top section of the roof melts first while the sides remain frozen, your attic is too warm, suggesting that your ventilation system is out of balance.
Visible signs of excessive attic moisture include: condensation, frost on rafters during the winter months, or a musty odor. Visible signs of moisture accumulation include water staining on your roof sheathing or noticeable humidity in your attic.
Signs of premature aging of your shingles include curled edges, cracked shingles, or excessive granule loss earlier than expected. If your roof looks like it has aged more rapidly than expected, poor ventilation may be the underlying cause.
Evaluation of Ventilation by a Roofing Professional
When evaluating a homeowner’s ventilation system, a qualified roofing professional evaluates the total square footage of the attic space and determines if the homeowner has sufficient vent space. The professional checks to determine if the homeowner has an adequate number of intake vents and exhaust vents, and if the intake vents and exhaust vents are clear of obstructions. The professional will evaluate if the homeowner has improperly vented bathroom fans and dryer ducts and inspect the insulation in the attic to determine if there are any obstructions to airflow. The professional will also search for visible signs of moisture damage.
If you experience any of the following: ice dams, high energy consumption, or premature roof wear, it may be due to poor ventilation of your home. Contact Giannini Roofing for a professional ventilation assessment and ensure your roof is protected year-round.
