Several styles of foundations can be used to elevate homes. In discussing foundation styles, it is beneficial to categorize them as open, closed, shallow, or deep. As the name implies, open foundations generally consist of piles, piers, or columns and present minimal obstructions to moving floodwaters. With open foundations, moving floodwaters, breaking waves, and smaller pieces of floodborne debris should meet relatively few obstructions and hopefully be able to pass under the home without imparting large flood loads on the foundation.
Open foundations have the added benefit of disrupting flood flows less than larger obstructions. This can help to reduce scour around foundation elements. On the other hand, closed foundations typically consist of continuous foundation walls (constructed of masonry, concrete, or treated wood) that can enclose crawlspaces or, as in the case of stem walls, areas of retained soils. Closed foundation walls create large obstructions to moving floodwaters and large flood forces can be imparted on them by breaking waves, floodborne debris, and the hydrodynamic loads associated with moving water. Closed foundations are also more vulnerable to scour than open foundations.
Elevated open foundations also create a unique design opportunitiy by creating a shaded, outdoor patio space beneath the home. Many homeowners pour concrete pads under their houses that can be utilized for parking and storage, or can even be painted and stained to add a more finished appeal to the space.
DID YOU KNOW? - Each additional foot your home is elevated above the required finished floor elevation reduces the insurance rate, up to 65% annually at the maximum additional height of 3’. One major benefit of elevating houses comes in flood insurance savings. FIND OUT MORE at the National Flood Insurance Program (NFIP).