What are the dirt marks on my walls, ceilings and what is this term "Ghosting"?

We're glad you asked!

Many consumers have been blaming markings and soot deposits on walls and ceilings on their new furnace and heating system. During the last year much research has been done to scientifically prove the causes.


Ghosting

Ghosting is a phenomenon that is generally seen during the winter months. Ghosting can be identified as dark lines on the drywall of ceilings and walls that outline the wall studs or the ceiling joists inside the living space. Even though insulation is installed between the joists themselves are exposed to the cold winter temperatures in the attic. Since the wood joists are not effective insulators, they act as thermal bridges. Consequently, the temperature at the underside of each joist (attached to the drywall) is lower than the adjacent sections of the drywall that are covered with insulation bats. The lower temperature along the bottom of the joists encourages the formation of microscopic condensation. Over time, the moisture will trap dust particles hat show up as shadow lines that outline the wood joists or studs.

To prevent ghosting, install insulation bats over the exposed ceiling joists. Ideally, the insulation should fill the spaces between the joists and cover the tops of the joists as well. The same holds true for the stud spaces; however, the fix would be more difficult.



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