What is a Crawl Space Foundation?

A crawl space foundation is a foundation built with room to move around under the foundation to inspect it and work on plumbing, heating, electrical wiring, and other utilities. This design has a number of advantages, and the cost varies, depending on the region and the height of the crawl space. It is important to build and seal a crawl space foundation well to address moisture issues, a common problem seen with crawl spaces in many regions of the world.

In a house with a crawl space foundation, instead of sitting on a slab or directly on the ground, the house is raised. A true crawl space is at least 18 inches (46 centimeters) high, but can be made higher to make it easier to work under the house. Utilities are installed under the home and can easily be accessed in the event of a problem, in contrast with a house on a slab, where it may be necessary to jackhammer into the slab for certain kinds of repairs.

Houses raised off the ground tend to have fewer mold and moisture problems because of increased air circulation and less wood to ground contact. Crawl space foundations that are not properly sealed, however, can create moisture problems in addition to making a house cold. The foundation should be sealed with a vapor barrier and vents should be installed to promote air circulation and prevent moisture from building up under the home. Installing good insulation between the crawl space and the home is also important. Periodic inspections of the foundation are recommended to check for leaks, mold, termites, and other problems that can develop.

When building with a crawl space foundation, people should think about the optimal height. While adding height adds expense, it can also save money in the future, in addition to making a home more pleasant to work on. A very low crawl space foundation requires people to literally crawl under the home and can be very uncomfortable and cramped when people need to do work. A higher foundation allows people to move more freely, facilitating easy inspection and repair.

Another option is a basement, a completely sealed foundation. Basements can be useful in a wide range of settings and many people like them for storage, storm safety, and other reasons. They also have moisture issues, an inherent problem with being at least partially underground. Basements need to be installed well with vapor barriers and vents and proper maintenance is key to prevent flooding and other problems.