Concrete fence posts

How to install concrete slotted fence posts and gravel boards

Posted on: December 18th 2023    •    Posted in: General News

Installing a fence may seem like a daunting task but with the right approach, suitable tools and materials, it can be a straightforward process.

Choosing your fence posts

The life of your fencing will be strongly influenced by the type of posts that you use, and concrete fence posts offer many advantages over timber options. Firstly, they are extremely durable and can withstand all kinds of weather and environmental conditions, including rain, frost and UV radiation, without rotting or warping. As a result, concrete fence posts can last for many years and do not carry the same maintenance requirements as wooden posts which need regular treatment and replacement in order to keep the fence in good condition.

Compared with timber, concrete fence posts offer significant strength and stability and are less likely to lean or bend in wet or windy conditions, which helps to maintain the integrity of the fence.

How to install concrete slotted fence posts

For slotted posts, you will typically need three types of posts. A corner post, which has 2 slots in the post, to accept two panels at right angles to each other. You will also need intermediate posts, which can also accept two panels, but this time on either end (so in a run of panels). End posts only have one slot in them and support just one panel.

Begin by measuring and marking the line of your fence carefully, ensuring it is straight and, if applicable, that you are observing any boundaries correctly. Using pegs and string will help to maintain a straight line.

Before you start digging, it is worthwhile to check for any pipes or electrical mains running under the ground so that you don’t damage them.

First of all, mark the correct position of the fence posts, according to the size and type of fencing you are installing. Dig holes for the posts, ensuring they are deep enough to provide stability. Typically each hole should be a minimum of 600 mm deep but this will be influenced by how tall the fence panels are, and the length of the posts to go with them. The general rule of thumb is that one-third of the length of the fence post should be in the ground, with two-thirds being above ground. If you are not sure, please contact us, and we will do our best to guide you. The width of the hole should be three times wider than the width of the post.

Place the posts in the holes and use a spirit level to ensure they are perfectly vertical.

We recommend using Postcrete rather than mixing concrete as it is a ready-to-use blend of selected sand, cement and additives especially formulated for fixing concrete and wooden posts.

Fill the hole with water to a third of the depth, and then pour in Postcrete around the post until no standing water is visible. Sprinkle water on top of the powder and position the post and check that it is level. It is best that the Postcrete sits proud of the ground and is sloped away from the post so that rain water doesn’t accumulate around the base. Use a trowel to smooth the surface and ensure a neat finish. Ensure that the Postcrete doesn’t stop the gravel board sitting flush on top of the ground. Allow the Postcrete to cure for the recommended time before slotting in the gravel boards. It needs to be sufficiently load-bearing to withstand the weight of the gravel board.

Make sure the gravel board is level, and if necessary, remove any soil or obstructions to make sure this happens.

Installing fence panels

Once the concrete has set correctly, you will need two people to lift the panels and slot them into the slotted concrete posts from the top. Gently lower the panels until they sit on top of the gravel board. Use a spirit level to check that the panels are level. Continue installing the rest of the panels.

Allen Concrete manufacture a wide range of precast concrete fencing. We offer both lightweight and heavy-duty slotted concrete fence posts, depending on your requirements. The advantage of slotted posts is that the panels can be easily replaced if needed. All of our slotted fence posts are wet cast to ensure a smooth finish to all mould faces. All of posts are available either with a round top or a pyramid top. The choice is a personal one but we find the round top posts are the more popular.

At Allen Concrete, we offer a range of precast concrete fence posts for all types of fencing panels and fence boards, all to British Standards, making us the go-to supplier for all fencing contractors, stockists and builders merchants. With sites in Northamptonshire and Surrey, our modern production methods and stringent quality control enable all of our fencing products to be produced in high volume to the same exacting high standard, post after post.

Contact our team for further help or, to place an order, email or call 020 8687 2222 (Mitcham) or 01933 276848 (Wellingborough).

Allen Concrete

35 Willow Lane

  020 8687 2222


35 - 37 Rixon Road

  01933 276848