Underside Of Roof Damp

The same phenomenon happens with roof systems.

Underside of roof damp.

That excess moisture ends up as drops of condensation on the roof. When this warm air reaches the spaces in the roofs it gets in contact with cold air and condenses. This leads to the formation of damp spots on the surface of the roof. When humid air from the interior makes contact with the underside of the roof surface the water vapor it s carrying turns into liquid water explains jose f.

Ponce technical specialist with professional roof consultants. As it cools it can t hold as much moisture. If attic air is humid and roof sheathing is cold condensation or frost can accumulate on the underside of the sheathing. The cause depends on whether you have an unconditioned attic or a conditioned attic.

The source of the attic moisture is usually indoor air that enters the attic through ceiling cracks. Picture a cloud of moisture floating overhead between the rafters. Warm wet air rises and meets the cold roof and cools. Warm air can contain more moisture than colder air.

Such cookers often allow for the quick rise of moist air leaving behind the cold air. Warm moist air enters the roof space through gaps in loft hatches or where bathroom plumbing or other services go through the roof space. Condensation will arise as a result of warm moist air penetrating up through the ceiling. Think of a cold drink sitting out on a summer day.

When this warm moist air hits the cold air in the roof space water droplets condense on the nearest cold surface the roofing felt.