Many homeowners think that the best way to maintain a safe and clean crawl space is by having plenty of venting throughout the area. However, many homeowners and maybe even builders alike don’t realize that venting is actually not all that beneficial– if not detrimental.
South Carolina Crawl Spaces
It’s been estimated that 70 percent of the homes being built in South Carolina have crawl spaces. Since many contractors don’t exactly want to put the extra time and expense into sealing and in other words finishing the space, most homes don’t come with finished crawlspaces.
What could happen when it isn’t sealed, insulated and finished with other beneficial products? Well, there’s mold, mildew, condensation, termites, high radon levels, and other environmental problems.
If that list sounds like a lot, that’s because it is a lot! Many homeowners are unaware of the influence the space has on their overall home environment but, the crawlspace– or basement for that matter– has a huge and vital effect on the home.
Encapsulated VS Vented
When encapsulated, it doesn’t have any vents and this is what every homeowner should want and should have beneath their home. This will help control the moisture and thermal issues that many South Carolina crawl spaces experience throughout the year.
As many South Carolina homeowners are aware, mold and decay occur a lot more often than necessary. In fact, if it weren’t for the condensation and high relative humidity, many of the issues would go away. So, how does condensation and relative humidity increase in the space?
Temperature
According to Craig DeWitt, PhD, PE, a specialist at RLC Engineering, LLC. and Larry Janesky, the owner and founder of the internationally recognized Basement Systems, Inc. network as well as CleanSpace Crawl Space Encapsulation System– venting worsens the environment.
“Venting a crawl space actually makes it wetter. A sealed one has several advantages. First, it’s dryer, decreasing the likelihood of mold and decay. In addition, wood is stronger when it is dryer, therefore the structure performs better. A decrease in moisture in the crawl space allows air conditioners to run more efficiently, since they have to remove less moisture from the air. Duct insulation also stays dry, maintaining the integrity of the insulation. Humidity levels within the crawl space and house are more uniform from season to season, creating less movement of hardwood floors, interior wood trim and cabinetry,” said DeWitt.
Relative humidity, says Janesky, defines how much water is in the air compared to the amount of water the air is actually capable of holding at a specific temperature. So, let’s look at an example of a typical hot and muggy day in South Carolina of about 90 degrees with 75 percent relative humidity. Then, let’s say your crawl space is 70 degrees, and the surface temperature measured along your walls is about 66 degrees.
When air is pulled into a crawlspace through a vent, the air is then cooled because as we have deduced, the outside air is hotter than the inside air. Then, when the air is cooled by even one degree, the relative humidity rises by 2.2 percent.
Returning to our example, this means that 90 degrees minus 66 degrees is 24 degrees. So we multiply 24 degrees by 2.2 percent and this means the relative humidity will be increased by 48 percent. The once 75 percent relative humidity is now 123 percent.
What Does This Increase in Relative Humidity Mean?
Once the relative humidity is raised above 100 percent, the dew point, the excess humidity is then released in the form of condensation. So, your entire space is now very, very wet. Once it dries out, the mold and fungi will come in to destroy the wood and other organic material.
Oh, and what’s the worst part? It’s been measured that about a third to a half of the air on the first floor of a home actually originates in the crawl space. In other words– whatever is in the space is in the rest of your home.
Repair– The Moisture Solution
Moisture comes from the soil, walls and vents. As a vapor barrier works hard to limit the moisture in your crawl space, you should also consider having a repair expert to encapsulate the space and close the vents.
