Knowing how to build the right foundation for your home and the soil it is built on makes John Wassmer Construction the leader in construction of foundations. A major cause of home foundation failure is land movement, or settling. Every building structure settles at one time or another. Any movement of the ground is likely to stress the foundation.
Here are important considerations before we begin.
- Load bearing capacity
- Water drainage
- Changes in soil moisture
- Differential settlement
Three Types of Residential Foundation
Crawl Space (Pier and Beam)
A pier and beam foundation consists of either vertical wood or concrete columns (piers) that support beams or floor joists above the ground. The areas between the soil and the bottom of the house floor is known as the crawl space. These foundations are built either at ground level or over a shallow excavation that varies in depth, but is commonly about 36 to 40 inches deep. The best crawl space foundations have a load-bearing concrete perimeter wall and concrete or steel piers, both having footings below the freeze line of the soil, along with a good barrier over the soil to keep moisture under control. Less expensive versions have no load-bearing perimeter walls, piers with shallow footings, and no moisture barrier at all over the soil. Crawl spaces that enclosed by a wall or by skirting must have vents on every side to allow air to circulate and help keep the soil dry under the home. These vents must be configured to prevent the entry of rodents and snakes. Crawl space foundations are most often used in areas where there is heavy clay content in the soil that can severely damage (crack) slab foundations, or in waterfront or flood prone building sites where the necessary floor height to prevent water penetration of the living space must be higher than a slab can normally provide. The primary advantages of crawl space foundations are that plumbing lines are readily accessible for repairs, and foundation settlement problems are easier and less expensive to correct than with slab foundations. A primary disadvantage occurs when these foundations are not properly maintained or are constructed without adequate ventilation, allowing water or pests to cause damage. Crawl space foundations without adequate insulation applied to the bottom of the house floor can be very energy inefficient in a cold climate.
A basement is a type of foundation which includes an accessible space between the soil and the bottom of the first floor of a home. This foundation provides living space below the home, below the ground elevation. It is basically a slab foundation with walls and a floor. Basements are most often built in cold weather climates such as the Northeast, Midwest and Rocky Mountains, and in places where the cost of excavation is not prohibitive. Basements start with a hole approximately 8 feet deep, however, some homeowners will opt for a 9 or 10 foot deep basement wall to increase height and volume of useable space. The floor and walls are built, then the house itself is built over that. Basement foundations have the advantage of providing useful space for utilities, mechanicals systems, and storage not available in the previous two types of foundations. The primary disadvantage of basements is that because they are mostly below ground level, they are vulnerable to leakage, mold formation, and flooding. Basements in wet climates must always have a working drain and pump in the floor to combat flooding.