Sealing a Crawlspace. Good or Bad?

There are still individuals in the construction industry that will question a sealed or conditioned crawlspace but this argument should be put to rest. Studies have shown significant improvements in the home efficiency and environment with the installation of a sealed crawlspace. According to a study conducted by Advanced Energy sealed crawlspaces, when properly installed, will perform better with relative humidity, wood moisture content and energy efficiency than a traditional vented crawlspace.

The study has shown that during the summer of 2003 the studied sealed crawlspace only exceeded 70% relative humidity only 5% of the time while the vented crawlspace stayed above 70% almost all the time. The wood moisture content in the sealed crawlspace stayed below 12% during the study while the vented crawlspace wood moisture varied greatly. Also the sealed crawlspaces showed an annual energy use reduction of 15% for sealed crawlspace with insulation on the floors and 18% for sealed crawlspace with insulation on the foundation wall.

Here are some of the main benefits to having a sealed crawlspace:

1. Improved Moisture Control
- A sealed crawlspace improves the moisture content of the space by preventing transfer of moisture through three of the main entrance points, the foundation wall, the soil floor and the foundation vents.

2. Pest Control
- By removing moisture from the space the appeal to subterranean termites is reduced.

3. Improved Efficiency
- As already stated from the study results a sealed crawlspace can improve the efficiency of the home.

4. Improve Indoor Air Quality
- A good number of contaminates can come from your crawlspace. By cleaning up the space and you may be able to improve the air quality of your home. A sealed space can reduce the mold content in the crawlspace and can be used or modified to prevent radon intrusion.

5. Improved Maintenance
- This is a non-intended benefit but due to the increased visibility and improved environment homeowners are more likely to “visit” the space leading to better home maintenance. Also if the insulation is installed on the walls the floor structure is visible and individuals are more likely to find problems around plumbing or HVAC.