Metal roofing is a great residential roofing option, thanks to its unique benefits, such as long life span, durability and energy efficiency. However, precautions must be taken to minimize condensation on it. In this blog, local roofing company Cantrell Roofing, LLC shares insight on condensation, and how it relates to metal roofs.
How Roofing Condensation Forms
Heat and moisture from indoor spaces tend to rise into the attic. Without proper ventilation, they get trapped in the attic instead of getting flushed out. Condensation forms when trapped humid air comes in contact with a relatively cooler surface in the attic. It could be uninsulated spots under the roof deck or an attic window with single-pane or uninsulated glass.
Condensation is a common problem among all types of sloped roofing. Increased moisture levels in the attic can cause damage to the roofing support structure, which is typically made of wood. Droplets from condensed moisture can cause attic insulation to form clumps upon contact, resulting in diminished roofing insulation that, in turn, result in diminished energy efficiency. A capable roof maintenance and repair company like us can address condensation after the fact, however, a preventive approach is ideal for this.
How to Prevent Roofing Condensation
A poorly-built metal roof is more vulnerable to corrosion, especially if it wasn’t built up to code. Some of these metal roofs don’t even have decking, which leaves the roof’s underside vulnerable to the effects of condensation. A properly-built roof should have the following features to prevent condensation in the attic:
Proper Ventilation — Roof ventilation consists of exhaust vents located at the ridges, and intake vents at the soffits. The negative pressure caused by released hot and moist air pulls fresh air through the soffit vents, creating continuous airflow that keeps the attic cool and dry.
Insulation — Condensation forms on surfaces cooler than the air in the attic, which is precisely what happens when the roof isn’t properly insulated against heat from the outside. Metal roofs are typically insulated between sheet metal and underlayment.
Vapor Barrier — Vapor barriers are sheets of material, typically made of polyethylene, that is installed behind the ceiling drywall. It’s intended to prevent moisture in the attic from infiltrating the drywall. Certain types of roofing underlayment serves a similar function.