Effects of Moisture on Roof Membranes

Roof membranes undergo a range of stress due to environmental and occupancy factors, such as humidity, temperature fluctuations, and air pollutants. Excessive moisture in the membrane can lead to degradation and, eventually, system failure.

Sources of Moisture

• Exterior: Rainwater, snowmelt, and condensation.
• Interior: Vapor diffusion from within the building (e.g., showers, cooking).

Consequences of Excessive Moisture

• Membrane Degradation: Hydrolysis (chemical breakdown) of membrane components, leading to reduced strength and flexibility.
• Mold and Mildew Growth: Organic membranes can become susceptible to biological growth, which can further degrade the membrane and indoor air quality.
• Corrosion of Metal Components: Moisture ingress can accelerate corrosion of metal roofing elements, such as flashing and fasteners.
• Leaks: Membranes can become compromised by moisture-induced damage, resulting in leaks and water damage to the building.

Moisture Tolerance

The moisture tolerance of a roof membrane varies depending on its material composition and design. Some membranes, such as TPO and PVC, are relatively moisture-resistant, while others, like EPDM, are more susceptible to water absorption.

Regardless of the membrane type, excessive moisture exposure should be avoided to ensure optimal performance and longevity. Proper ventilation, moisture barriers, and regular maintenance are crucial for mitigating moisture-related issues.