**Atlanta Air: Cheap Vapor Barrier Inflaming Summer Lungs?**
By Franklin Everett ShawThe air in Atlanta in August can feel like swimming through soup. It’s not just the heat; it’s the oppressive humidity that clings to everything, seeps into your clothes, and makes breathing feel like a chore. But what if I told you that the very structure of your home, designed to protect you from the elements, might be making the problem worse? Specifically, that seemingly innocuous plastic sheet tucked away in your walls – the vapor barrier – could be contributing to the respiratory woes so many Atlantans experience during those sweltering months.
The culprit isn’t the vapor barrier itself, but its misuse, particularly in a climate like Atlanta’s. These barriers, intended to prevent moisture from migrating into walls, can inadvertently trap moisture already present, creating a breeding ground for mold and releasing harmful volatile organic compounds (VOCs). This is especially true in older homes where air sealing isn’t perfect, and moisture can find its way in through cracks and gaps.
Let’s dive into the science. Vapor barriers, typically made of polyethylene plastic, are designed to slow down the movement of water vapor. In colder climates, they’re installed on the warm side of the wall (the inside) to prevent moisture generated by indoor activities like showering and cooking from condensing within the wall cavity. However, Atlanta’s climate is hot and humid for a significant portion of the year. This means that during the summer, the outside air is often warmer and more humid than the inside air, especially if you’re running your air conditioning.
When a vapor barrier is installed on the inside of the wall in Atlanta, it can prevent moisture from escaping outwards. This trapped moisture can lead to several problems:
- Mold Growth: Mold thrives in damp, dark environments. Trapped moisture within walls provides the perfect conditions for mold to flourish. Mold spores can then be released into the air, triggering allergic reactions, asthma attacks, and other respiratory problems. Many Atlanta homes, particularly those built before stricter building codes, are especially vulnerable.
- VOC Release: Many building materials, including some types of insulation, adhesives, and paints, release VOCs. These chemicals can contribute to indoor air pollution and cause a range of health issues, including headaches, dizziness, and respiratory irritation. Trapped moisture can exacerbate VOC release, as it can break down materials and increase the rate at which they off-gas.
- Wood Rot: While less of an immediate health concern, trapped moisture can also lead to wood rot, compromising the structural integrity of your home. This can be a costly problem to fix and can also create further opportunities for mold growth.
So, what can Atlanta homeowners do to mitigate these risks? The key is to understand how moisture moves through your home and to implement strategies that promote proper ventilation and moisture control.
Here’s a step-by-step guide:
- Assess Your Home’s Vapor Barrier Situation: Determine if you have a vapor barrier and where it’s located. If you’re unsure, consult with a qualified home inspector. They can use moisture meters and other tools to assess the moisture levels in your walls and identify potential problems. Pay special attention to basements and crawl spaces, as these areas are often prone to moisture issues.
- Improve Ventilation: Proper ventilation is crucial for removing excess moisture from your home. Ensure that your bathrooms and kitchen have exhaust fans that vent to the outside. Use these fans whenever you’re showering, cooking, or doing anything that generates moisture. Consider installing a whole-house ventilation system, such as an energy recovery ventilator (ERV) or a heat recovery ventilator (HRV), to bring in fresh air and exhaust stale, humid air.
- Dehumidify: A dehumidifier can help to remove excess moisture from the air, especially during the humid summer months. Choose a dehumidifier that’s appropriately sized for your home and set it to maintain a humidity level of around 50%. Regularly clean the dehumidifier to prevent mold growth.
- Consider a “Smart” Vapor Retarder: Instead of a traditional vapor barrier, consider using a “smart” vapor retarder. These materials, such as CertainTeed MemBrain, allow moisture to escape when humidity levels are high but restrict moisture from entering when humidity levels are low. This can help to prevent moisture buildup within walls while still providing some level of moisture control.
- Address Leaks and Water Intrusion: Fix any leaks in your roof, plumbing, or foundation. Ensure that your gutters are clean and properly draining water away from your home. Seal any cracks or gaps in your walls and around windows and doors to prevent water intrusion.
- Monitor Indoor Air Quality: Consider using an indoor air quality monitor to track the levels of VOCs, mold spores, and other pollutants in your home. This can help you to identify potential problems early on and take steps to address them.
- Professional Help: If you suspect that you have a serious mold problem or if you’re unsure about how to address moisture issues in your home, consult with a qualified mold remediation specialist or a building science expert. They can conduct a thorough assessment of your home and recommend the best course of action.
One common mistake developers make is assuming that a vapor barrier is always necessary, regardless of the climate. In Atlanta, a more nuanced approach is required. Another pitfall is improper installation. A vapor barrier that’s not properly sealed can actually trap more moisture than it prevents.
For example, consider a home in Decatur, Georgia, built in the 1970s. The original construction included a polyethylene vapor barrier on the interior side of the walls. Over time, small leaks developed in the roof, allowing rainwater to seep into the walls. The vapor barrier prevented this moisture from escaping, leading to significant mold growth and wood rot. The homeowners experienced persistent respiratory problems and eventually had to undertake a costly renovation to remove the mold and replace the damaged wood. They opted for a “smart” vapor retarder and improved ventilation to prevent future problems.
Another scenario involves a new construction home in Buckhead. The builder, following standard practice, installed a vapor barrier on the interior side of the walls. However, the home was not properly ventilated, and the homeowners experienced high humidity levels indoors. This led to condensation on the windows and mold growth in the bathrooms. The homeowners had to install a whole-house dehumidifier and improve ventilation to address the problem.
The key takeaway is that vapor barriers are not a one-size-fits-all solution. In Atlanta’s humid climate, they can actually exacerbate moisture problems if not properly installed and managed. By understanding the principles of moisture control and implementing appropriate strategies, Atlanta homeowners can create healthier and more comfortable living environments. Don’t let your home become a breeding ground for mold and respiratory problems. Take control of your indoor environment and breathe easier.