Wallpaper on exterior walls, especially in older homes, is a bad idea!
So how exactly can wallpaper lead to mold? Keep reading to find out.
Are all homes at risk?
Normally, moisture from outside moves through the walls in the form of water vapor, and evaporates into drier indoor air. This moisture would then be removed from the air and expelled out of the house as a byproduct of the HVAC system heating or cooling the air.
Most older homes were constructed without an adequate vapor barrier in the walls. Homes without vapor barriers absorb more moisture from the outside air than newer, more energy efficient homes.
How does wallpaper lead to mold?
When wallpaper is applied to exterior walls, this water vapor becomes trapped. During the summer, the problem is compounded by the temperature differential of warm outdoor air and cool indoor air. Condensation begins to form on the backside of the wallpaper, leading to mold growth and even degradation of the drywall.
If you choose to install wallpaper in your home or commercial building, limit the application to interior walls, especially when using vinyl wallpaper.
Can I just kill the mold with bleach and paint over it?
No! Normally, by the time a homeowner realizes that he has a problem, the solution involves removing the wallpaper and affected drywall and cleaning mold off of wall studs and other framing components. Read more to learn why cleaning mold is more important than killing it.
If the problem has gone undetected for quite a while, the wooden framing components may have rotted. The moisture inside the walls may also attract termites.
Wallpaper leads to mold in a 1960s brick home
Last week we did a mold inspection to determine the cause of mold in the master bedroom of a local home. The homeowner thought the mold may have been the result of a roof or plumbing leak. During the inspection, we checked the dryer vent, roof, plumbing, window and gutter downspout in the adjacent area to determine the moisture source that caused the mold problem. We systematically eliminated each possibility until the true cause, the wallpaper, was identified.
The brick home was built in 1968 without a vapor barrier in the walls. The wallpaper that was on the exterior wall was acting as a vapor barrier and trapping moisture. The problem was made worse due to an HVAC system supply vent in the floor at the base of the wall that was obstructed by a dresser, causing the supply air to be directed at the wall.
During the summer, the combination of warm moist air moving through the wall from the outside, wallpaper that was trapping this air inside the wall, and the vent blowing cold air directly on the wall lead to excessive moisture inside the wall and mold growth.
How Branch Environmental can help
Branch Environmental is a full-service mold inspection, assessment, and remediation company. Contact us today if you see, smell or think you have mold.
We’re here to help whether you’d like to schedule a mold inspection, request a remediation estimate, or simply have questions regarding mold or indoor air quality.