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The crawl space does a number of things for the home. It elevates the house off of the ground (especially important in damp areas) and accommodates variations in the topography of the site. Ductwork, electrical wiring and plumbing run through the crawl space, making them easier to service. The concrete foundation wall is what creates the crawl space. The foundation distributes the weight of the structure and its occupants, and at the same time, holds the wood frame structure of the home to the ground in case of heavy winds or earthquakes. Within the concrete foundation wall is reinforcing steel. This reinforcement is what enhances the concrete's strength. Concrete is very good in compression, and steel allows for tension strength. Concrete girder pier "pads" scattered in the middle of the crawl space are there to support the posts and beams in the crawl space. These beams in turn support the I-joist for the main floor. Under-floor areas, such as the crawl space, are ventilated by openings in the exterior foundation walls or joist bays. These openings are specifically located to provide cross ventilation, and are screened with corrosion resistant wire mesh. A challenge that arises in crawl spaces and basements is dampness. In order to keep water out, perforated pipe and gravel are used in a trench around the crawl space to route water away. The drainage system also handles water that might get into the crawl space. That's why we slope and trench inside to allow for water to escape. The pipes and gravel are then backfilled with dirt that slopes away from the house to drain. |