What is Ghosting?
Have you ever had strange dark marks that form on your ceiling or walls along the frame of the building? While you may think this is mold or leaking this is most likely Ghosting. Ghosting is when particles in the air, soot, dust, or dirt, collect along the frame of your house. These marks get darker and more numerous the longer they are allowed to form and if left untreated can create much worse issues.
These marks are caused by poor insulation and high interior humidity which allows cold air to penetrate the ceiling and walls causing the frame to change temperature and begin attracting condensation, this is called thermal bridging. This temperature change and increase in condensation in turn allows particles to stick to the studs and frame creating the dark spots visible on the walls and ceilings.
How to Prevent Ghosting
Ghosting is mainly an internal issue and fixing the insulation is usually the only 100% sure fire way to remove the stains. Painting over these stains won’t keep them covered as the soot will reappear through the paint, and the main issue of condensation is not taken care of. There are a few things though that can help to decrease the size of the stains and stop them from getting worse. The first thing you can do is decrease or stop use of candles and other burning oils like cooking oil.
This decreases the number of particles in the air. You can also decrease the number of particles by replacing filters and regularly dusting and vacuuming. Another way to help is decreasing the humidity inside your house to under 55%. This can be done with dehumidifiers or simply running bathroom vents or fans out of the house.
These remedies can only do so much however and as stated earlier re-doing the insulation is likely the only way to remove these stains completely as it stops the true source of the condensation by creating a better barrier between the air outside and the interior walls. The problems with the insulation that cause ghosting can only get worse and lead to more severe issues like mold down the line if left unaddressed.