How to Install Foundation Support Piers

Choose an area that is known for stable soils. Unstable soils are no good for post and beam, especially for the do-it-yourselfer. Soils should be well packed, with little clay. The reason to use a post and beam is to keep the wood off the wet soil. This will preserve the wood. If the soil is unstable, your best bet is to lay a slab-on-grade upon a gravel base. All of this should be ascertained long before you decide to buy a piece of land.

Find an area with decent drainage. In general, this refers to a slight slope to one side. You can adjust your piers to compensate for this later. What is important is that a well-drained area will make the soil that much more stable and packed over time. Constantly wet, freezing and thawing soils will destroy even the best post-and-beam work.

Space the pier holes 3 to 5 feet apart. These dimensions depend on the size of the pier and the type of home. A simple cabin or bungalow requires piers 3 to 4 feet apart at most on each side. Larger houses might use 15 piers total, depending on their length. Erring on the side of more rather than fewer is always best.

Dig your holes about 15 inches into the ground. Each hole should be about 16 inches in diameter. In most places, this will be well below the frost line. You cannot bury your concrete footer in ground that will freeze. Usually, 15 inches is more than enough.

Line the bottom of the hole with gravel. This will add stability. Place the concrete footer into the hole. The pier is then mortared onto the footer. The footer is not absolutely necessary, but it does add stability. For simple projects, such as a hunting cabin or large shed, crushed rock will do fine. For a home, the concrete footer is either poured or bought precast, and delivered to the site. The pier will be sticking up a minimum of a foot out of the ground. The ideal pier will be almost 18 inches out of the ground. This will give you a spacious crawlspace for storage or later pipework. The tops of these piers should already be arranged to receive the post, since most store-bought piers are already outfitted for this purpose.