How deep to dig fence posts?

Many different factors affect the durability and stability of your fence. One of them is the use of appropriate depth of excavations under the profiles. Are you planning to build a galvanized mesh fence or panels? From our article you will learn how to deeply concrete fence posts and what else is worth remembering when preparing excavations.

The depth of the holes for the posts matters

The poles, fixed around the border of the property, carry a mesh or fence panels for many years and resist various types of forces and external factors: winds, moisture, changing temperatures or trees growing around them. When the hole under the post is too shallow, the fence does not have good support, and this in turn contributes to the formation of defects, and in the worst case – to the need to replace the posts.

What can happen if you embed the post too shallowly? There is then a high probability that it will tilt after stretching the mesh or putting on fence panels due to intense downpours, as well as seasonal freezing and thawing of the ground, which may turn out to be unstable, blown up.

What depth under the fence posts?

There is no single, simple answer to the question of what should be the depth of the trench for the fence post. This is due to the fact that each plot has its own specifics, including: a different type of soil, the depth of ground freezing or the angle of inclination of the terrain. You also need to know that in mountainous and coastal regions, where there are strong winds, the depth of the trench for the post is crucial and determines the durability of the fences.

Specialists in the fencing industry recommend placing 1/3 of the post underground, which gives a depth of about 50-80 cm – the higher the profile, the deeper you should dig it. Deep excavations, at the level of 80-100 cm, are less often used for panel and mesh fences (more often they occur in gabion, prefabricated or forged fences). 

How to dig deep into a fence post: practice and norms

Making a shallow hole under the post means less concrete wear, lower cost of the post itself and shorter digging time. Many people who decide to install the fence themselves are looking for savings on material, downplaying building standards and the division of land freezing zones, which, in their opinion, should be taken into account only when building utility connections and building foundations. If the fence is to be used for several more decades, however, pay attention to the zone in which your plot is located and take it into account when building the fence.

Freezing the ground means that it increases in volume due to the freezing of water particles in it. This is a natural phenomenon that can cause concrete to be pushed upwards and cracked. In Poland, there are 4 ground freezing zones, namely:

• Suwałki region: the depth of ground freezing is 1.4 m,

• north-eastern region: Białystok – Łomża – Braniewo, Krosno district – Nowy Sącz: 1.2 m,

• central Poland, i.e. the belt: Gdańsk – Warsaw – Kraków: 1 m,

• Western Poland: 0.8 m.

Are you planning to erect a fence permanently and you want it to be aesthetic and durable? Take into account the given depths of ground freezing both during the construction of the fence foundation and the preparation of individual excavations for posts.

What is the depth of the trench for the posts of temporary or forest mesh?

What depth should be the holes for wooden posts intended for the installation of temporary, construction or forest fences? Measure 1/3 of the height of the stake and on the basis of this value prepare a trench. If the ground is uneven or unstable, you should deepen the holes by 10-20 cm, and then carefully stiffen the posts with sand, mixed with aggregate.

In temporary fences , corner poles play an important role (they take on significant loads) and initial poles, to which the entrance gate is attached. Make sure that the depth of the excavations under them is at least 70-80 cm, making the structure more stable.

The depth of excavations for fence posts: who is right?

On online forums and amateur videos, available on the web, you will currently find hundreds of different opinions and advice on how deep to dig fence posts. Some advise to prepare a pit with a depth of 40 cm, while others suggest 50, 60 or 70 cm. Who is right and where to get knowledge about the technique of assembling posts? Use common sense when analyzing other people's opinions and keep in mind that these are rarely expert advice.

If you want to build a fence yourself, talk to a technical advisor from a fencing company like STAL who will tell you how and how to dig deep into the posts. A lot of important advice and information about the specifics of your land will also be provided to you by an authorized surveyor, for example when making field measurements. When erecting a fence, you should use only tips from professionals involved in construction, because only thanks to them you will build a safe and functional fence.