The fear of hidden mold gives rise to visions of mold remediation experts traipsing around inside specialized enclosures, while demolishing your home at tremendous expense to you. If you have noticed moldy odors or water damage, perhaps it is time to consult with a mold expert. However, for the large majority of homeowners who have not noticed the symptoms of mold growth, now is the perfect time to start looking.
Most are familiar with Stachybotrys, the "toxic black mold", which is common to water damaged gypsum wallboard. This mold organism requires high moisture availability, known as water activity, to develop. Optimal growth is achieved at .98 water activity, which is a lot of moisture. Big black patches, powerful odor, and lots of water, usually make this mold hard to miss. The real danger of hidden mold is the ability for a small mold problem to develop into a large and expensive one before being noticed. Wallpaper can help make that possible.
Wallpaper is more than a decorative wall covering. In fact, any large surfaced item or treatment added to a wall, such as bookshelves , paint or wallpaper, can alter the vapor and thermal performance of a wall. This knowledge is particularly important for the perimeter walls of the home, but should be a consideration for some interior walls, as well. There are other factors to consider, but in general; moisture moves from warm areas to cooler areas. So, in the summertime, warm moist air tries to make its way indoors where it is cooler and, in the case of a bathroom, warm moist air from bathing activities migrates to cooler areas. A well designed wall will slow the progression of moisture through the wall and yet allow it to pass through before trapping too much moisture and encountering psychrometric conditions that would permit condensation. Many wallpaper types impede moisture migration at the most crucial location, the coldest surface of the wall. The obstacle also makes possible a higher water activity in the underlying wallboard that leads to hidden mold growth.