A crawlspace is one of the most important, yet most overlooked, areas in a home. A properly designed crawlspace can serve as an insulating layer between the home and ground which will help the home stay cool in the summer and warm in the winter. However, a poor crawlspace can cause a variety of problems, some of which are even worse than energy loss. A problematic crawlspace may have too much humidity which can result in the growth of mold in the crawlspace. In fact, most homeowners do not even realize that there is a problem in a crawlspace until they notice a moldy smell or begin experiencing allergies or other respiratory problems caused by mold in the crawlspace. While crawlspaces can cause a lot of problems, there are a few simple things that can be done to make certain that a crawlspace is both energy efficient and unlikely to develop a mold problem.
Humidity in a crawlspace is a primary indicator of a problem. Too much humidity will mean that moisture will form on the surfaces in the crawlspace, and moist air will escape into the home, according to Crawlspace Depot. When crawlspace surfaces become moist, they can begin to rust or rot and mold will eventually start to form. Moist air in the home will make the home feel warm, causing those in the home to lower the thermostat temperature to feel comfortable. To test for humidity in the crawlspace, a homeowner will need to use a hygrometer. Thermo-hygrometers are a combination device that measures both temperature and humidity. Modern thermo-hygrometers are electronic devices that make periodic readings and store the reading for later retrieval. A homeowner can have a thermo-hygrometer placed in the crawlspace to monitor the crawlspace for humidity problems.
A crawlspace should have a vapor barrier that prevents moisture from the ground from coming up into the crawlspace. In essence, a vapor barrier is plastic sheeting that is placed on the ground under the home. The sheeting should be sealed as much as possible to prevent air movement. Sheets can be laid side by side to make a barrier, but solid sheeting is much more effective. Sheeting should be sealed to the walls of the crawlspace to prevent air from moving around the sheeting. Once in place, a vapor barrier will restrict air movement into and out of the crawlspace from the ground. This will help to stabilize both the humidity and temperature in the crawlspace.
The decision of where to insulate in a crawlspace is determined by the climate where the home is located. In areas that receive prolonged periods of freezing weather, it is best to insulate the walls of the crawlspace. Wall insulation will help to seal off the crawlspace from the cold weather. By sealing out the cold, the crawlspace will act as a pocket of warm air under the home and help to reduce winter heating costs. Wall insulation will also help prevent water and drain lines from freezing in colder weather. In warmer climates, it is best to insulate under the home, between the floor joists. Insulation under the floor boards will help to prevent energy loss from the home, while air can move more easily in and out of the crawlspace.
While vapor barriers are important to prevent moisture from the ground from entering a crawlspace, every crawlspace will inevitably have some moisture. To deal with this moisture, some air movement is necessary in and out of the crawlspace. Air movement is especially important in warm, wet climates. To facilitate a controlled exchange of air, vents can be placed in the walls of the crawlspace. The best vents are those that can be opened and closed as needed to deal with moisture and heat. In colder climates, vents should be left open in warm weather and shut during colder weather. Vents can be adjusted according to hygrometer readings to maintain a low level of moisture in the crawlspace. In especially moist conditions, a dehumidifier may be needed in the crawlspace to remove excess moisture.