Common Causes of Mold Growth in Bathrooms or Hallways
In older homes mold is often found growing on the walls, on the ceiling, and on the top edges of walls in bathrooms and hallways. Many contractors can become confused by the location of this mold because there are no apparent plumbing problems, no roof leaks and no visible water damage. However, when you take a closer look you may notice that attic air is entering the home. Recessed lights should be removed from any room where mold is present.
The most common air infiltration is a hallway attic pull down stairs, a whole house attic fan, or recessed lights. When the heating and air-conditioning system comes on it can create negative air pressure within the home, that negative air pressure pulls in hot, and at times humid air. When this hot air meets colder walls it causes minor amounts of condensation. Now given a few weeks or even months over a hot, humid, or rainy summer the walls can start to develop visible mold growth. The mold is usually only on the surface of the walls when these conditions exist. A way to remedy to stop the attic air from entering the hallway is that attic stairways can have enclosures built over them and house attic fans can have foam enclosures built over them. One product that is designed to block the air from leaving the attic is called The Attic Tent. These tents are designed to be energy efficient and at the same time they are built to block humidity and reduce mold grown. Once air filtration has been stopped the walls need to be cleaned with disinfected and then scrubbed and rinsed with a new damp rag at least three times. After getting the walls cleaned and wiped down, they should then be painted with a mold resistant product such as Zinsser Perma White. The walls must be prepared according to the manufacturer’s recommendations. This is also the ideal time to add insulation to your attic area. The lack of insulation can promote mold growth, but more often when mold is found in the hallways it is due to attic air infiltration.
Mold is often also found in bathrooms. When people call to have their bathroom investigated, many times there are no larger problems with the bathroom other than the daily use of a bathtub or shower. Showers and bathtubs provide a continuous stream of water. Typically a bathroom should be cleaned weekly to prevent mold and other related problems. There are too many products out there to list that help aid in cleaning your bathroom. A disinfectant removes 99.9% of fungi and bacteria with a low toxicity level is recommended. We suggest avoid using bleach type or tilex products as these products can be very dangerous to use and can burn the lung tissue if inhaled, they also require lots of outside air flow.
Bathrooms should be investigated to determine if the problem is just a lack of cleaning and maintenance or if there are hidden problems such as leaks in the wall or subflooring. Most people may not have a thorough enough understanding of their plumbing and home construction to determine the difference between a cleaning problem and a legitimate problem with their bathroom. Often there are other places that provide odors that are overlooked such as the first floor bathroom of a concrete slab house under the bathtub/shower unit. Typically when a concrete slab is poured there is an 8”x8” area left open to the soil for the plumbing. This soil is rarely if ever covered back up and soil gases, moisture and odors often enter through this soil. If enough humidity enters it can and will promote mold growth within the walls and under the bathtub. Often this can be reached by taking out the sheetrock from an adjacent room and the space can be sealed.
When in doubt hire a professional to inspect your home. Finding problems sooner than later will save you money. Removing and preventing future mold will create a healthier home environment.