Excess moisture, introduced by way of dirt, vented crawlspaces, contributes to wood rot, fungi growth and increased pest activity, including infestation and colonization. Moisture in crawlspaces migrates to the upper levels of the home through a “stack effect”. In essence, whatever air is below the house moves inside the house, mixes with the air conditioning, and carries odors and contributes to poor indoor air quality and uncomfortably high humidity levels.
Moisture Due to Stack Effect Contributes To:
- High Humidity
- Pest Infestations
- Poor Indoor Air Quality
- Mold Growth
- Musty Odors
- Damage to Property
As warm air rises and escapes through the upper levels of the home, new air finds its way into the home to replace what’s been lost. Intake air comes in at the lower levels – through the dirt crawlspace.
Homes that have properly treated and sealed wood, installed permanent crawlspace liner with closed foundation vents, and a professional dehumidifier are protected from both the humid outside air and the ground’s natural moisture. The really big benefit is that this strategy minimizes fungi and mildew growth, guarantying a more structurally sound and healthier home.
Building Science Experts Agree About Crawlspaces
Building Science Corporation says that crawlspaces are real simple to understand and deal with. When you vent crawlspaces you bring in hot, humid air and cause moisture and mold problems.............Moisture moves to the cold surfaces. Venting dirt crawlspaces made sense only when you had no air conditioning and no insulation and no crawlspace walls.
In the picture below, the customer put the house on the market and the person that bought the house explained that he did so because of the condition of the crawlspace.
This diagram shows the "stack effect".
Air flow always moves from bottom to top.
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