Underside Of Roof Damp

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.

Underside of roof damp.

As it cools it can t hold as much moisture. In the event of the attic not being properly ventilated this would condense on the underside of the roof. Warm wet air rises and meets the cold roof and cools. Picture a cloud of moisture floating overhead between the rafters.

Warm moist air enters the roof space through gaps in loft hatches or where bathroom plumbing or other services go through the roof space. The source of the attic moisture is usually indoor air that enters the attic through ceiling cracks. If attic air is humid and roof sheathing is cold condensation or frost can accumulate on the underside of the sheathing. This leads to the formation of damp spots on the surface of the roof.

Such cookers often allow for the quick rise of moist air leaving behind the cold air. The same phenomenon happens with roof systems. When this warm air reaches the spaces in the roofs it gets in contact with cold air and condenses. Essentially condensation occurs at night when the temperature inside a building is warmer than outside.

That excess moisture ends up as drops of condensation on the roof. Think of a cold drink sitting out on a summer day. Warm air can contain more moisture than colder air. When this warm moist air hits the cold air in the roof space water droplets condense on the nearest cold surface the roofing felt.

Ponce technical specialist with professional roof consultants.