Crawl spaces are widely known as rotting, humid, dank spaces. There's a reason for this: they ARE, more often than not, rotting, humid, and dank. Unfortunately, what happens in the crawl space does not stay in the crawl space- as part of your home, a rotting, sagging crawl space will eventually affect everyone and every room in the house.
A rotting, sagging crawl space will eventually have to be fixed. Failing to do so will lead to the first floor sagging and caving in, wood support beams and sub floors failing, odors, and an unhealthy home environment. Additionally, if your crawl space is rotting, it's almost definitely vented. Besides being the source of the problem, crawl space vents will also allow in cold air in the winter and warm air in the summer, resulting in a drafty home and higher utility bills.
The "Stack Effect"
In a home, air is continually moving upwards throughout the home. Warm air rises, and when it reaches the attic and upper floors, it finds its way out of the house. As this happens, a vacuum is created in the lower floors. New air is pulled in through the crawl space and lower levels of the home.
This means that you're breathing in the air in your crawl space. And along with this air, you're breathing everything in it, including mold spores, dust mite waste, dander from rodents, odors, and anything else.
Vented Crawl Spaces
Crawl space vents were designed with good intentions. The idea behind them is that, when they're installed, they will create a crosswind in the crawl space- one that will keep air circulating throughout the space, naturally keeping the crawl space dry and at an acceptable humidity level to help prevent mold and rot.
Unfortunately, venting a crawl space is, simply put, a bad idea. In fact, it's debatably the worst building policy ever introduced. Crawl space vents introduce outdoor temperatures, humidity, mold, insects, and animals to the space. And because of the stack effect, the air doesn't go out through though one vent and out the other, it goes upwards.
Crawl Space Humidity
During the summer, outside air is hot and humid. The crawl space, however, is cooled naturally by the earth, and it remains at a constant temperature of about 50 degrees. When hot, humid summer air enters the crawl space through the vents, it's cooled in the crawl space, and the humidity skyrockets.
As the humidity reaches over 100%, the excess moisture in the air is deposited on anything nearby, including wood, metal, and all other cool surfaces. And as the air rises upwards, so does the humidity. Because humid air is much harder for an air conditioning system to cool than dry air, and this causes your cooling bills to rise significantly.
High Heating Bills due to Crawl Space Vents
In the winter, humidity in the crawl space is not as significant a problem. However, the winter season still leaves a vented crawl space open to the elements, including the cold. As this cold is pulled into the crawl space, it affects everything in the space. Furnaces, water heaters, hot water pipes, heating ducts will all be cooled, forcing the utilities to work harder just to maintain status quo. In addition, the cold air will seep upwards, cooling the floor above, making for an uncomfortable surface to walk on and a drafty, uncomfortable home. The cumulative cost of this energy drain is extremely high!
Crawl Space Mold and Rot
As humidity fills a crawl space, it leads to the rotting and decaying of the crawl space. The area will continue to degrade until the floor is caving in, the structure is compromised, the insulation is falling to the floor, and the organic building materials in the space have rotted beyond repair. Click to read more about crawl space mold and rot!
Crawl Space Structural Problems
If a crawl space problem is caught early enough, rebuilding and replacing the wood in the space may not be necessary. Instead, more permanent options, like sealing off the vents, installing a vapor barrier, and adding crawl space structural supports may be the way to go. Click to read about crawl space encapsulation or click to read about crawl space structural supports!