Define Crawl Space

Construction

• Crawl spaces under the house must be built solidly with sturdy materials, as the crawl space is essentially the foundation of the home. A common strategy is to use stacks of cinder blocks to provide the height of the space, and surround the space by a brick wall. You must take care to ensure an even and equal height of the cinderblocks and brick, as the floor of the building goes on top. Crawl spaces are also constructed from wood which has been treated to prevent moisture and insect damage.

Purpose

• A crawl space lifts the home off the ground, which allows for easy access to the home's foundation. With a crawl space, maintenance of the home is easier than if the home were built on a concrete slab, at ground level. The plumbing, pipes, heating, wiring and structural support are all easily accessible via a crawl space. This allows you to diagnose any problems more easily and cheaply than if such equipment were in the attic of the home or buried within a concrete slab. The distance from the ground a crawl space provides also ensures against water damage from rain and ground moisture.

Ventilation

• Traditionally, crawl spaces were ventilated, or unsealed, so that flowing air would prevent buildup of humidity. However, ventilation allows cool air to flow under the home, which can increase energy use to heat the home and thus increased energy costs. Another concern is that ventilation will not provide further dryness if the air outside is not drier than the air in the crawl space, for instance, in a humid climate in summertime. Many professionals, as well as the U.S. Department of Energy, now recommend that the crawl space be unventilated, or sealed, to prevent these issues and increase energy efficiency.

Insulation

• Along with sealing your building's crawl space, the U.S. Department of Energy suggests that you insulate your crawl space. You can insulate both ventilated and sealed crawl spaces. Materials for insulation include rigid foam board, batt insulation and spray foam. Insulation ensures against freezing pipes and increases energy efficiency.

Health

• Crawl spaces, especially ventilated and poorly insulated ones, pose certain health risks. Moisture buildup in the space provides an ideal home for mildew and mold on surfaces, particularly cardboard, wood and drywall. Rodents, dust mites and other pests also may leave feces in your crawl space. Air from the crawl space travels into the home, and brings with it the potentially toxic air from the crawl space. This can initiate or exacerbate health problems such as asthma. Proper sealing and insulation can minimize or eliminate these concerns.

Common Usage