Infrared imaging helps explain location of fungal growth on exterior wall

Flir One infrared image of exterior wall Feb 2017 - N. Carlson

The blue and purple colored areas are colder than the yellow and red areas on this infrared photo taken with a FLIR One infrared camera attached to a Samsung cellphone.

Dark areas of mold growth on an exterior sheetrock wall.

The space was used to store books and other materials.  The interior relative humidity was measured at 46%.  This allowed for condensation on the metal roof deck and for the equilibrium relative humidity on the sheetock over the metal studs to be greater than 70%.