What Is the Difference Between a Crawl Space & a Concrete Slab?

Construction

• One of the most prominent distinctions between a concrete slab and a crawl space is in the construction. A concrete slab is considered to be the easiest option for a foundation. It requires the least amount of site work and labor. The concrete is poured directly onto the ground and only requires forms around the edges. Prior to pouring the concrete, a moisture barrier is created with gravel covered by plastic sheeting.

  A crawl space allows for open air between the ground and the house. In some homes, a concrete base is poured. In others, only concrete footings and stem walls are constructed. The sides of the crawl space are constructed using cinder blocks with a brick facing. If the ground is not level, the blocks and bricks are layered with varying mortar thickness to create a level base.

Infrastructure

• An important element to consider before choosing a concrete slab or a crawl space is how it affects the infrastructure of the home. If a concrete slab is used, the plumbing and electrical conduits must be installed prior to pouring the slab. In some cases, the home's pipes are actually embedded in the concrete. Embedded plumbing poses an impediment to any future maintenance and repair.

  With a crawl space, infrastructure items are more readily accessible. The home's plumbing system, as well as some wiring, ductwork and other utility areas, are often located in the crawl space, offering more convenient access for repairs and additional utilities.

Climate

• Geographic location and climate are important factors in choosing a type of foundation for a house. Concrete slabs do not do well in a cold climate. If the ground freezes, the slab is subject to shifting which can result in structural damage. The concrete also acts a conductor, sending the cold into the bottom floors of the house. House construction in moist climates may fare better with a crawl space foundation. It raises the house above ground level allowing air to circulate underneath it. This is also a better option for climates that foster termite propagation.

Miscellaneous

• If price is a factor in choosing a foundation, a concrete slab may be slightly less expensive, but both options are significantly cheaper than constructing a full basement. A concrete slab offers extreme durability. A crawl space offers easier access to pipes and other utilities, but can become a haven for bugs and rodents. A crawl space is equipped with slotted windows that should be adjusted for weather and temperature changes. It is important to keep the moisture level low in a crawl space to prevent the growth of mold and mildew. Prior to choosing a foundation type, check on local zoning laws to determine if restrictions are in place.