What should be the diameter of the opening for the fence post?

Do you want to fence your plot or construction site and are wondering what the optimal diameter of the hole for the fence post should be? The depth of the wells depends on several factors, including: the type of fence and the locally occurring soil. So how to prepare the holes correctly? In this article you will find some practical tips.

Holes for fence posts and soil type and properties

Soils, occurring in Poland, differ from each other in physical and chemical properties, such as: structure, density, tendency to shrink or relax. So before you start building your fence, check what kind of ground you are dealing with to properly strengthen your fence.

What type of soil is on your plot? There are 2 simple ways to find out. The first of them consists in the analysis of extract data from the land register, and the second – on self-assessment during an on-site inspection. Soils can be:

• clay: you will know them by their compact structure and viscous consistency, they are heavy, impermeable, plastic, it is difficult to make a hole in them for posts, but after the work is completed, the trench is even and stable; 

• sandy-loamy: formed from the combination of clay and sand particles, they are lighter and less plastic than loamy soils, they tend to retain water and fall off, which makes it difficult to maintain the desired diameter of the trench;

• sandy: the lightest of the listed types of soils, easily permeable to water, are not plastic, and after the formation of a hole under the post, it is difficult to maintain the set diameter of the hole in them, if there is no top layer of humus on them.

• 

The diameters of the holes you will determine with a drill

Do you have an extensive plot of land? To make holes for fence posts , you will use a manual or diesel drill. If the soil is compact and clayey, use a flue gas drill to quickly and effortlessly prepare a place for wooden stakes or steel profiles. Deciding on a drill, you will get a precise, standard hole diameter: 20 cm or 30 cm.

In shops and rental of construction equipment, you can also choose smaller augers with a diameter of 10-15 cm, but they are not suitable for making holes for posts of permanent fences, except for  forest, temporary and electric fences (shepherds). Small drills are also used successfully for hammering poles and stakes for climbing plants.

How to make holes for fence posts?

Do you want to put a fence in the form of system fence panels or a grid and concrete the posts? Whether you're using a regular spade or drilling rig on unstable, water-retaining or uneven ground, as well as for tall pipes and punches, keep 25-30 cm in diameter of the hole and take care to maintain this distance throughout the height of the trench. 

The holes, 30 cm wide, can be filled with sand ballast, fine rubble or aggregate, thanks to which the concrete posts will gain greater stability, and the fence will serve many years intact. When making holes in the ground, also consider the economic issue – remember that the wider the hole for the fence post, the more concrete you will use.

What holes to make under the fence posts?

For mesh fences, or consider making two types of holes: under the initial and corner poles , make holes wider, 25 or 30 cm, and under the remaining, middle pipes, 20 cm in diameter is enough. Similarly, proceed when preparing a temporary fence and take care of a solid stiffening of the corner stamps.

Do you want to install a forest mesh around a recreational plot? You do not need to concrete the holes for the stamps, so holes 1-2 cm wider than the diameter of a wooden post, which on average is about 10 cm, will suffice. If you are left with a narrow gap in the hole, cover it with earth, harden the ground, you can also stabilize the stamp with side supports.

What hole under the system fence post?

How to determine the diameter of the hole for the steel profile of the panel fence? Its value depends on the specificity of the soil and the weight of the fence. Most Polish manufacturers recommend maintaining 20-25 cm in unstable, sandy-loamy or sandy terrain and falling at a large angle.

When making holes for posts for a permanent fence, remember that ultimately it is to serve a dozen or even several dozen years. A hole too narrow will not fulfill its function and will quickly be affected by various external forces, water and frost. The depth of the trench is also of great importance in the context of its stability, so make sure that it is adapted to the specifics of the soil and the height of the fence.