Pier foundations were common in older houses. Newer home designers prefer to have continuous perimeter concrete foundations, such as full-height basement and crawl space (concrete block) designs. In modern applications, pier foundations are typically used for decks, sheds, and other smaller structures.
Like a Table
Pier foundations are put together somewhat like a table. A series of concrete pads or footings are laid out at regular intervals. These pads often consist of a section of 4x4 treated lumber encased in a prefabricated concrete shell. This enables wooden posts to be nailed to the pads.
On a larger scale, large cylindrical tubes containing steel reinforcing bars (rebar) are used as forms for poured concrete. These tubes are made essentially from dense cardboard and designed somewhat like the tube at the center of a roll of paper towel. The form can be peeled away after the concrete is set, revealing a large concrete pier. This application is most common for large decks on slopes or second-story decks.
Reinforced concrete piers may also be square or rectangular, in which case the forms are built from wood or a combination of wood and steel. In all larger piers an anchor bolt is also cast into the concrete, protruding vertically out of the top, for securing posts or beams to the pier.
Falling out of Favor
Pier foundations have fallen out of favor with homebuilders because they are not as strong as other designs. Homeowners who often build their own decks, tool sheds, and other small structures, will find pier foundations an inexpensive and doable option.
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