A Pattern of Condensation in an Attic

Posted by in Attic Ventilation, Buying/Maintaining a Home, Winter Concerns | June 18, 2018

The feature photograph shows a view of the ridge in an attic.  Note the discoloration and biological growth on both slopes.  Notice that the discoloration is worse on the slope left of the ridge than on the slope right of the ridge.

What would cause the difference?

There could be a few reasons:

  1. The slope left of the ridge could be the north slope, which is commonly colder than the south slope.  The prolonged cold temperature of the north slope promotes more and longer wetting from condensation resulting in more wetness and biological growth.
  2. The roof deck on the left slope could be of a different material than on the right slope.  Some roof deck materials are less permeable or provide ingredients than are more favorable to biological growth.