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Picture of mold in the attic

Why Should I Care About Moisture in the Attic?

Moisture issues in the attic are often overlooked yet stem from common household activities that generate significant moisture. As warm air rises from the living space, it carries moisture with it, seeping into the attic through poor sealing and insulation. Addressing these underlying causes is essential in preventing the potential hazards of mold, mildew, and wood rot that can compromise the structural integrity of your home.

Causes of Attic Moisture

Attic moisture generally starts from within the home. Everyday living creates so many sources of moisture in the attic in ways that we never think about. Many sources from within our homes are hard to avoid, such as cooking, showers, baths and cleaning clothes. Other behaviors can be adjusted more easily, such as unvented heaters, overuse of humidifiers, unmanaged moisture in a basement or improper ventilation of exhaust fans. For example, many homes have these exhaust fans in the kitchen and bathrooms to remove moisture from these areas. When working properly, these fans are great for removing excess moisture from within the home. However, the fans create new problems if they are not properly venting to the outdoors. It is not uncommon to see improper installations with these fans blowing all of that moisture directly into the attic space instead of outside. 

Photo of condensation in an attic

All of the moisture created in the home seeps up into the attic. As you may remember learning in your school science class, warm air rises and acts as a transport for the moisture. As a result, most moisture in the attic comes from the warm moist air in the living space. The moisture transfers into the attic because of poor sealing and insulation between the attic and conditioned space. By sealing and insulating the attic properly, a barrier is created between the two spaces. These steps are necessary to reduce the warm moist air from rising into the attic where it then gets trapped.

Effects of Attic Moisture

This moisture generated from the home along with improper venting can cause not only moisture in your attic, but if left unresolved can lead to mold, mildew, and wood rot. According to HGTV, “the chief cause of attic mold is poor ventilation.” Fortunately, the issues that arise from the excessive moisture buildup are often easy to detect.

Visible Signs of Moisture Issues

Photo of stained roof decking with mold

Look for any of the following to indicate moisture issues in the attic:

  • Widespread water droplets, or if cold, frost along the ceiling of attic
  • Water stains indicating condensation was present 
  • Mold or fungal growth covering wide areas
  • Signs of any wood rot or decay
  • Peeling exterior paint
  • Roofing deterioration
  • Pests such as carpenter ants or termites

Solving Attic Moisture

Attic ventilation serves the purpose of keeping your attic cool while maintaining a warm living space. Despite sounding counterintuitive, having a cold attic can be advantageous. In regions with extended periods of heavy snowfall on your roof, a warm attic can potentially lead to the formation of ice dams, particularly in colder northern climates.

To prevent moisture related issues in the attic, it’s imperative to establish a barrier between the living space and the attic. Without this barrier, warm and humid air from within the house can seep into the attic. Once this warm air comes into contact with the cold roof deck or surface, it can quickly condense, leading to the formation of moisture. This condensed moisture on the attic surface is the root cause of concerns such as mold growth and wood rot. When frost or snow blankets the roof, it becomes apparent that some parts of the attic are warmer than others. Assuming that sunlight isn’t disproportionately affecting any particular area, those areas with melted snow indicate that the attic’s warmth is infiltrating from the inside. Identifying these spots is crucial in pinpointing any breakdown in the barrier between the living space and the attic.

The importance of proper attic ventilation cannot be overstated when it comes to safeguarding your home from the effects of attic moisture. By ensuring that your attic remains well ventilated, you can potentially avert the issues caused by moisture. A properly ventilated attic is not only a key element of home maintenance but also an essential aspect of preserving the integrity and comfort of your home.

Post Author: ATMOX TOM