What Can We Tell from This Photo? (Case Study 13)

Posted by in Apparent Mold/Biological Growth, Case Studies, Roof, Winter Concerns, Wood | February 22, 2016

The feature photograph was taken in an attic during a warmer month of the year.  It documents the condition on the underside of the roof deck.  This photograph provides valuable information regarding the scope and history of airborne moisture in the attic.

From this photo we observe the following:

  1. The darker discoloration on the plywood deck is biological growth, probably mold.
  2. The degree of discoloration indicates that the conditions for mold growth, that is, prolonged exposure to excessive airborne moisture, have been favorable for an extended period of time.
  3. The degree of mold growth on the fracture surfaces of the splintered plywood at the abandoned nail hole (just below the nail that is penetrating through the deck) compared to the relatively clean fracture surfaces at the splintered plywood at the penetrating nail indicates that excessive airborne moisture was present prior to the removal of the nail from the abandoned hole and prior to the driving of the penetrating nail.
  4. The corrosion at the tip of the penetrating nail and the slight discoloration on the fracture surface at the nail indicate that the the condition of excessive airborne moisture has also been present after the driving of the penetrating nail.
  5. The great number of checks in the surface of the plywood deck indicate that the deck has been exposed to excessive heat also.  The conditions of excessive heat and excessive airborne moisture indicates that the attic is probably inadequately ventilated.
  6. The spots of mold on the lighter discolorations of the mold indicate that the mold growth has occurred over multiple seasons.