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Installing Concrete Fence Posts and Gravel Boards

Why use concrete fence posts?

There are advantages and disadvantages to all types of fence post when choosing which one to use, but concrete posts remain a popular choice for garden fencing:

PROS

  • concrete is a robust and strong material with a long lifespan
  • not susceptible to rot or insect attack
  • maintenance free
  • easily withstands high windspeeds
  • fence panels are easily dropped into position, and damaged panels can be replaced quickly

CONS

  • heavy and cumbersome to install
  • less visually appealing than wood or steel
  • security - if the fence panels are not fixed in position they could potentially be removed by a determined thief

Which type of concrete post?

Steel reinforced concrete fence posts come in two main types- those for use with fence panels, and those for use with feather edge fencing - with each type having end posts, intermediate posts and corner posts.

Slotted concrete posts for use with fence panels have a deep groove down one or more sides, allowing a fence panel to slot in from the top once the post is secured.

Those for use with feather edge boards and rails, morticed concrete posts, have pre drilled holes and notches to insert rails and arris rails.


How to install a concrete fence post

Concrete posts are secured in the ground with a mixture of ballast and cement or  post mix concrete. Post mix concrete is a ready to use premixed cement which only requires water to activate - we recommend 1.5 bags per hole.

Dig your hole to the correct depth, allowing for the height of the fence panel and the gravel board. As a rough guide the hole should be a minimum 1/3 the height of the fence, so a 6 foot fence would need an 8 foot post in a 2 foot deep hole. 

Similarly, the hole should be three times the diameter of the post. To avoid having to cut a concrete fence post to size (which is laborious and throws out toxic concrete dust) you can always set your post deeper into the ground.

Digging a hole may sound like a simple task, but a long, narrow fencing spade will make this task much easier if you have multiple holes to dig, and a post hole digger will make light work of removing soil from deep holes.

Position the post in the hole, check the levels, then back fill with either a mixture of ballast and cement or post mix concrete. Be sure to leave the concrete slightly proud of the ground to avoid rainwater collecting at the base of the post. Keep on checking the levels, and adjusting the post if necessary, until the concrete has hardened. Post mix concrete will begin to harden after around 20 minutes, but the post can still be adjusted after this time.

Lay your gravel board in position on the ground and use this to line up your next hole. To ensure that your entire run of fencing is straight, use a taught  Builders Line and pegs to align the holes.


Installing concrete gravel boards for panel fencing

The gravel board is the protective layer between the ground and your fencing material or panel, providing a solid base to the fence and protecting the fence from groundwater. 

When erecting panel fencing with slotted concrete fence posts, the concrete gravel boards simply slot into the posts from the top, and can then be bedded into the concrete at the base of the posts for additional stability.

TOP TIP - rub an old candle down the grooves in the post, this will make it easier for the gravel board and fence panel to slide in


Installing concrete gravel boards for closeboard fencing

Installing a concrete gravel board onto a concrete post for closeboard fencing is slightly more complex. 

The gravel board specifically for featherboard fencing is attached to the post with a galvanised steel cleat that pushes into the pre-drilled holes at the base of our concrete posts. Secure the gravel board to the cleat with M8x80mm or M10x80mm bolts and washers.

Because of the longer length of this type of gravel board (2.885 metres) care should be taken during handling to avoid cracking.

Once installed, the gravel board centre is supported by a centre stump, which is attached by a coach screw and washer through a hole in the gravel board. The centre stump also attaches to the bottom arris rail, giving the whole structure total rigidity.


Ask the fencing experts

For further advice about your fencing project don’t hesitate to speak to our fencing experts at your local AVS Fencing & Landscaping Supplies branch. Our ranges of high quality concrete fence posts and gravel boards have different delivery options by product range, either click and collect from your local AVS Branch or home delivery within our AVS Branch delivery area. Each product is clearly marked with its delivery options. 

13th Apr 2021 AVS Fencing & Landscaping Supplies