Humidity and Odors in Your Raleigh Crawl Space & Basement

For the last 100 years, we have basically ignored that damp, ugly space under our homes. We use the space as a place to locate mechanical, plumbing and electrical to save space and to keep these things out of sight. However, the crawl space is much more than just a storage space for equipment. The crawl space is an integral part of your home. The EPA says that 65% of all the air on the first floor of your home comes from the crawl space. So, if your crawl space is a damp, dirty and moldy area, then this is the air you are breathing inside of your home!

The History of Problem Crawl Spaces

Crawl spaces in general do not make sense. We have made attempts over the years to try to address the unique issues inherent to a crawl space. In the 1800’s and early 1900’s, homes were built on stone or brick piers, with no exterior walls. This method allowed a lot of air to move under and up into the house. This caused the house to be drafty and cold in the winter months. It also allowed animals easy access under the house, which caused obvious problems. We then started to build walls around the bottom of the house to stop the cold drafts and animals and the traditional crawl space was born.

Once the walls were built, this created another problem. The air under the house became stagnant, and odors started to build. The solution was to add foundation vents to relieve the stagnant air and also to cross-ventilate the space. Soon after, we started to add vapor barriers to try and stop the moisture from coming up through the soil. Some agreed that the vapor barrier should cover all the soil in the crawl space, while others said that some moisture is needed and that we should cover only 80% of the ground. Powered foundation vents were also introduced. These fans were installed to pull humidity from the crawl space and expel it to the exterior.

Where the Problems Have Lead

As time passed and additional studies have been done, we now know there are several problems with foundation vents and passive ventilation in general. The first major problem is that in the South, we are trying to use very hot, humid air to cross-ventilate the cool, damp crawl space. This can cause several problems in the crawl space such as:

  • Heavy condensation
  • Wet insulation
  • Sweating duct work
  • Mold
  • A damp environment that attracts bugs and insects

Another misconception is that a 6mil vapor barrier that is laid on the crawl space floor will stop moisture from coming out of the ground. Unless a vapor barrier is totally sealed to the walls and columns are tightly sealed at the seams, it can never stop the hydrostatic pressure that builds and pushes through the gaps and unsealed seams. A simple vapor barrier is just not enough to prevent moisture problems.

The only solution to prevent moisture, mold, odors and pests is a sealed crawl space! Sealing the crawl space stops the bad air from entering the foundation vents, and also prevents the moisture from coming up from the ground. It will make your home more energy efficient and will greatly improve the air quality in your home.

For more information about a sealed crawl space, contact Crawl Space and Basement Technologies at 919-847-7072.