Fence Posts - Fence Post Caps
A fence is only as strong as the posts securing it, so it is important to pay attention to the selection and installation of your fence posts.
Wood fence posts
These are among the most commonly used fence posts, and can be secured in several ways. The fence post ends can be installed directly in the ground, secured to hard surfaces with a bracket, or driven into the ground with a spiked bracket, among others. Installation with brackets lends lateral strength, and is helpful in preventing rot by keeping the wood away from soil and water.
However, the most common installation technique is to install the post directly into the ground. Be sure to dig the post holes deep enough to provide lateral strength. Using pressure-treated lumber for this type of installation greatly increases the longevity of your posts. Note that if you cut pressure treated lumber, you should coat the cut ends with preservative – the factory preservative does not permeate the entire diameter of the wood.
Be careful when using concrete to secure wood fence posts. A common mistake is to put concrete in the post hole before inserting the wood post, which allows the concrete to form a cup around the entire bottom of the post. Instead, put the post in first, then the concrete, which will form an open-ended concrete collar around the post. The reason you should do this is that the concrete cup method will hold water, rotting your posts from the bottom up much faster.
For high tension wire fences (like farm fence) that utilize wood posts, wire tension cannot be maintained by relying on the lateral strength from burying the fence post ends underground. In these cases, above-ground wood tensioning structures are used. Corners are reinforced with triangular structures, and mid-fence runs are often reinforced with a wood rail between posts where the post tops are being pulled by the wire tension towards each other.
Metal fence posts
Metal fence posts are installed similarly to wood posts, with some design consideration differences. Metal does not have the same rot issues as wood, so can easily be installed directly in soil, secured with brackets, or encased in concrete. However, you should only install metal posts into soil for very light duty fencing such as silt fencing, snow fencing and the like. Because the lateral profile of many metal fence posts is small, most are installed in postholes filled with concrete to strengthen them.
A key consideration to metal fence posts is the gauge, or metal thickness, of the posts being installed. Many homeowners and commercial establishments choose thinner gauge posts because they are less expensive, and are less than pleased with the performance of the fence if it is subjected to lateral forces (climbing, bumping, animal activity, or inadvertent contact with moving automobiles) that cause the fence to partially or fully fail.
PVC fence posts
PVC fence posts act much the same way as metal, and are installed similarly. They can be inserted directly into the ground, attached to brackets or inserted in concrete. Because they are impervious to water, rot issues are non-existent. Recent innovations in the manufacture of these posts greatly increase their strength and longevity over earlier models.