Structure of a Barn

The Barn's Foundation

• While most buildings have a concrete foundation which is dug and poured deep into the ground, a barn is a pole building, and the foundation is built by anchoring vertical poles on a 12-inch round by 18-inch tall concrete pad 36 to 48 inches in the ground under each pole. Barns are typically built with a dirt floor because they store heavy equipment that would crack a traditional concrete pad. Once the poles for a barn are anchored, the walls are framed by "post-framing," a method which is much stronger than traditional stick-built construction.

Wall Framing

• With the construction of a post, you can make an inexpensive frame for the barn. This construction method is also one of the simplest ways to frame a building. The post frame consists of horizontally applied 2-by-4's which are called girts that run around the perimeter of the poles. The girts are used to pull the vertical poles into position. A double header, which is a pair of 2-by-10's, one on each side of the vertical poles, is attached at the top of the poles. The header supports the trusses, or roof rafters. Due to all these components, the need to create a foundation of concrete is eliminated and financial savings are increased because of the speed at which a pole building is constructed.

Roof Rafters vs. Trusses

• The roof can be built using rafters or engineered trusses. These elements can be in the shape of the traditional two plane, pitched roof or a gambrel style, four-plane roof. Newer barns are usually built with pre-engineered trusses, while older barns were built by hand, using a system of support beams inside the building that framed the roof rafters. Before installing the roof, barn owners should determine which building shape better suits their needs. Pre-engineered joists are manufactured used in factories and shipped to the construction site ready for installation. Rafter-style roofs are built on site from dimensional timbers and lumber and require additional support framing inside the building.

Barn Siding

• Many options are available in barn siding. Wood sidings are used in many barns for rustic charm, and the traditional red barns that dot the U.S. countryside are an example of how long a well-constructed barn will last. More modern barns are sided with plywood, metal or vinyl siding. These manufactured sidings install much faster and therefore cut the owner's construction costs. Sidings can be placed horizontally or vertically and their durability depends on the type of material used.