Metal roofing is durable and fire- and insect-resistant. However, this material is known to "sweat," a process in which condensation collects on the underside of the roof. This happens when the metal is cool and the temperature inside a home is warmer. Condensation can lead to moisture damage, mold growth, and leaks. Here are a few ways you can reduce the risk of your roof sweating. 

How to Prevent Roofing Condensation

1. Measure the Pitch

The pitch of metal roofing can determine how likely sweating is. When the pitch is 6 degrees or less, condensation can collect and build in the corrugated areas because there isn't enough slant to help moisture flow downward. Before installation, talk to your roofer and design a structure with sufficient pitch to help moisture drip instead of linger.

2. Ventilate


When there is sufficient airflow, condensation quickly evaporates, preventing moisture issues. A ventilation system with holes and openings at the eaves and in gable walls allows air to flow easily, making condensation less likely.  

3. Insulate

Sweating occurs when the temperature of your metal roofing material is below the dew point of the air inside your house. By prioritizing insulation, you'll keep heated air in your living spaces while preventing your roof from reaching a low temperature that leads to sweating. Spray foam insulation and traditional fiberglass insulation in the attic and the walls will help curb the problem while enhancing comfort and energy efficiency. 

4. Install a Membrane

To mitigate water damage, leaks, and possible corrosion, install a membrane or anti-condensation layer along the underside of the roof. This added line of defense, typically composed of polyester and rubber, will serve as a buffer, collecting condensation droplets and helping them evaporate. 


If you're concerned about condensation, contact Tory's Roofing & Waterproofing Inc. in Pearl City, HI. With nearly five decades of experience, this third-generation family business is proud to serve clients across Oahu with a commitment to timely, quality roof repairs. To schedule an estimate, call (808) 456-5990. For more information on their services, visit their website.