NJ Attic Mold Prevention
Often when homeowners see visible mold growth in their attics, they see a black growth on attic sheathing and rafters. It is rarely the potentially toxic Stachybotrys mold because attics are not consistently wet and are not damp enough to sustain this kind of mold. In the media, there seems to be a lot discussed about “toxic” and “non-toxic” mold. In reality, people can have respiratory sensitivities to any type of mold – and it should be removed no matter what particular strain of microfungi has taken hold in your home.
It is common to find black mold on the attic sheathing of a gable roof (the triangular portion of a wall between the edges of a sloping roof that is shaped like an inverted “V”). Very often the north-facing roof is most severely affected because it receives little sun during the day and doesn’t warm up enough to accelerate evaporation and drying out. In severe cases, water can be dripping from the roof shingle nails that penetrate the sheathing; the sheathing will be blackened and even delaminated from moisture and mold.
Attic ventilation is critical. In a cold winter climate like New Jersey, inadequate ventilation of the attic space can lead to excess humidity and moist air from the warmer rooms infiltrates into the attic around plumbing pipes, the attic hatch, or even recessed lighting fixtures. The moisture in the air then condenses on surfaces that are below the dew point. Just because roof vents have been installed doesn’t mean they were installed properly. Sometimes the external component of the vent is installed as “window dressing,” but the required opening in the roof sheathing or soffit trim was never cut. Roofers installing ventilation must cut the openings in the wood before installing ridge and soffit vents and they should install a roof vent that actually works.
Even with the best attic ventilation, a home can still have a serious mold problem if too much moisture enters the attic from the house. For example, bathroom and dryer exhausts vented into the attic instead of the outside can lead to condensation. If there is localized mold growth above the bathroom or laundry area, the bathroom vents and dryer exhausts should be re-vented directly to the outside. If there is widespread mold growing on the attic sheathing and the attic is well ventilated, it is critical to find and eliminate the source of moisture. A mold problem is a symptom of a water problem and if you want to eliminate mold the water problem must be addressed and corrected or the mold will inevitably return. Attic ventilation is important, but controlling the leakage of moisture into the attic is arguably more important.
An unbalanced heating or cooling system can create attic condensation. Your air ducts are one of the most important systems in your home, and if the ducts are poorly sealed or insulated, especially in unconditioned areas, it can add hundreds of dollars to your heating and cooling bills. Sealing ducts to prevent leaks is especially important in unconditioned areas such as attics and crawlspaces. If the supply ducts are leaking, heated or cooled air can be forced out of unsealed joints and lost; in addition, unconditioned air can be drawn into return ducts through unsealed joints. Air entering the system from a damp basement or crawlspace can wind up in the attic leading to moisture and mold.
Mold of any type in an attic may be a problem for those who are sensitized if the mold emits an odor or is disturbed such as when homeowners using unfinished attics as storage spaces disturb the growth. In finished attic spaces, mold can grow on carpeting or on walls that have been dampened by roof leaks around chimneys or plumbing venting pipes.
Signs of excess moisture in attics during the winter are condensation or frost on roofing nails. In the summer, watch for condensation on attic ducts or other piping to the indoor AC unit. Even though mold in the attic is “hidden,” it is not a problem to be ignored. Those mold spores, once airborne, can spread anywhere throughout the home.
