(October 31, 2012
The “Ghosting” effect, also called Thermal Tracking by building technologists, shows up as dark stains on interior walls and sometimes on drywall ceiling surfaces. This happens when warm and damp indoor air circulates through the house and touches cooler spots of the perimeter walls and condenses. Household air which is full of debris sticks to these damp surfaces leaving a stain over time. Stains show a silhouette of the wall framing behind the drywall surface.
This effect is often prominent with defects in the building insulation and ventilation system. Settlement of wall insulation or inadequate installation creates voids, cold spots in the wall cavity. Inadequate ventilation can also develop when new installation of carpeting may restrict air flow under the interior doors ways. Higher than recommended humidity levels within the home can also contribute to Thermal Tracking. This problem is more related to wood frame condos and houses.
The remedy for fixing this problem is combination of the following:
- Fixing air leakage in the house
- Improving missing or inadequate insulation in the exterior walls
- Improve indoor air ventilation by installing a proper HRV system (Heat Ventilation Recovery system)