Crawl spaces are the shallow spaces beneath a home's first floor, between the ground and the floor joists. Crawl spaces typically provide ventilation to protect framing members from moisture damage, as well as space for the home's plumbing and electrical components. Most types of flooring are suitable for installation over a crawl space.
Wood floors and engineered wood flooring do not perform well in the presence of moisture. If the crawl space has any moisture problems, then wood products should not be used—the moisture will make the flooring rot and cup, especially around any crawl space access doors in the floor. However, wood and engineered wood floors can be used safety if a vapor barrier has been installed in the crawl space to prevent moisture from traveling up through the floor.
Most types of tile can be used above crawl spaces, unless there are significant moisture problems in the crawl space. The major exception is any crawl space access door in the floor. Ceramic and stone tile will be too heavy and too difficult to install on the access door. Tile floors usually require an special underlayment on top of the subflooring.
Carpet can be installed on floors located above crawl spaces, although it can be damaged if the crawl space has moisture problems. If carpet is installed in a basement that has a crawl space below, the basement subfloor should be well-sealed with a vapor barrier.
Laminate floors can be installed above crawl spaces, but as with wood floors, the crawl space must be covered with an appropriate vapor barrier and have proper ventilation. If these conditions aren't met, laminate floors can cup from excessive moisture.