Installing fence posts is an important part of a fence installation project. To ensure that fence posts remain in place, it's necessary to secure them using postmix / postcrete or another form of concrete. When using postmix / postcrete, determining how many bags are needed per fence post depends on a few factors, such as the size and type of fence post.

When choosing which fence post to use, the size and material of the fence post will affect how much postmix / postcrete you'll need for each one. Fence posts can range from small 75MM x 75MM posts to large wooden 150MM x 150MM gate posts. The larger and heavier fence posts usually require more postmix / postcrete for a secure installation. Generally, two 20KG bags of postmix / postcrete should be used for every four inch fence post that is set at the recommended depth of 600MM

It's also important to consider the soil type when installing fence posts with postmix / postcrete. Soil type plays an important role in determining how much postmix / postcrete is required for each fence post; loose soil may require a deeper hole, which means more postmix / postcrete because it does not provide as much support as densely packed soil and gravel would when setting fence posts into place. Although postmix / postcrete is designed to increase adhesion and buy time before the fence posts set completely, it cannot fully compensate for poor soil conditions. Before starting your project, assess the ground where you plan to install your fence and determine if it needs any improvement or additional materials such as gravel before beginning your installation process.

Once you've determined which type of fence posts you need and where you plan on installing them, calculating how many bags of postmix / postcrete you'll need per fence post is relatively simple. As a quick reference guide: two bags of postmix / postcrete will cover two feet (or 60 centimetres) of a 4” diameter fence post in moderately compacted soil;  additional bags may be necessary for larger gate posts.

In conclusion, knowing how many bags of postmix / postcrete are needed per fence post greatly depends on several key factors: size and material of the chosen fencing posts, type of ground they will be placed into, as well as their spacing apart from each other along your chosen fencing area perimeter line. By accounting for these details properly before starting your project, you can avoid having too little or too much concrete mix when completing your fences' foundations!