November 19, 2020
Are Metal Roofs Noisy?
If you’ve ever gone outside before sunrise, you’ve likely noticed dew on the grass or on your car windows. This is condensation. While we may have learned the basics of this naturally occurring phenomenon in science class, we may need a quick refresher.
Condensation occurs when there’s more water vapor (the invisible, gaseous phase of water) than the air can hold. When the water vapor is cooled off or compressed to its saturation limit—at which point the vapor’s molecular density reaches its maximum threshold—it turns into liquid. Warm air can hold more moisture, but as it cools it reaches its saturation limit and water droplets form. While not a problem on the grass or your car (once you wipe the water away), condensation on metal panels CAN be a problem for your customers. The good news is there’s a simple solution.
When temperature and humidity conditions reach dew point, moisture can condense on the underside of metal roofing and potentially cause water damage to the inside of your customer’s building. Those drips from ceilings and surface moisture occur when warm air comes in contact with the cooler roofline or walls.
High interior humidity—a common cause of condensation in metal buildings—can result from heating and air conditioning systems, how the building is used, gas-fired heating components, improper construction techniques or even human respiration, as these all give off moisture vapor.
If there is an abundance of condensation, water droplets will form and can cause damage. In metal buildings, there are a few possible consequences of trapped moisture in wall and roof systems:
Note: The probability of significant problems will depend on the location and usage of your customer’s building.
Controlling Condensation: What is the Solution?.
Traditionally, condensation is managed by insulating the metal roof so that the panel temperature never reaches the dew point. This is often accomplished using vinyl-backed fiberglass insulation to prevent humid air from coming into contact with the cooler metal roof (which may be at or below the dew point). If your customers are heating or cooling their building, adding insulation is certainly worth consideration. If they aren’t, there is another option to consider besides the installation of vinyl-backed insulation.
Your customers can consider installing Drip Stop, a patented condensation control membrane, to prevent damage from moisture. Drip Stop (manufactured by ABC) is a felt-like material with a rubber backer that can be applied to the back side of metal panels. The material literally traps and holds the moisture resulting from condensation. When conditions change, the ambient air temperature usually rises, thereby raising the dew point. The moisture is then released from the Drip Stop material back into the air in the form of normal humidity. Drip Stop can be applied to the back of metal coils (either Galvalume® Plus or painted) and then the metal can be roll-formed onto panels.
Drip Stop offers several advantages for your customers:
There’s no need for the damaging effects of condensation to put a damper on your customer’s metal building project. With a simple solution like Drip Stop, you customers can protect their assets and prevent costly and time-consuming repairs.