Stopping Metal Roof Condensation

Metal gets cold faster than other items so condensation begins on metal first.

Stopping metal roof condensation.

That excess moisture ends up as drops of condensation on the roof. Warm wet air rises and meets the cold roof and cools. Condensation on metal roofs can be a problem once the weather starts to get cold. Why metal shed and garage roofs get condensation it took me a while to work this out but if you think of the way a solar still works that is what is happening to your shed roof.

Condensation happens when moisture filled air contacts anything that is below the dew point temperature. 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. Metal roofs are known for this with condensation forming particularly at the beginning and end of a day.

Picture a cloud of moisture floating overhead between the rafters. As it cools it can t hold as much moisture. It can lead to roof leaks even if rain has not occurred for several days. Essentially condensation occurs at night when the temperature inside a building is warmer than outside.

Placing foam insulation on the roof would prevent the metal roofing from reaching dew point on the interior.