How to erect a concrete fence post

Video by The Carpenter's Daughter. This guide is inspired by the practical walkthrough "Concrete Fence Post Fencing DIY" from The Carpenter's Daughter, the UK DIY channel run by Vikkie Lee. She covers the whole job clearly and honestly, including the bits that catch people out — like how much the posts move when you're tamping postcrete and why checking level at every stage saves you from pulling posts back out later.

1. Mark out the fence line and post positions

Knock in a couple of timber stakes at each end of the fence run and stretch a taught string line between them at the height you want the top of the posts. This gives you a straight reference to work against and stops you drifting off line mid-job.

Standard concrete post spacing for most panel fences is 1.83 m (6 ft) centre to centre, to suit standard-width panels. Mark each post position with a cane or marker spray. Double-check the distance between every mark before you start digging.

2. Dig the post holes to the right depth

A solid rule of thumb is one third of the total post height in the ground. For a 6 ft fence that typically means a 1.8 m post, so you are digging roughly 600 mm deep. Add 100 mm extra at the bottom for a layer of gravel or hardcore to help drainage.

A post-hole borer makes this manageable, especially in clay. A sharp spade and a lot of effort will do it too. Try to keep the hole walls reasonably square — a neat hole holds the concrete better than a cone-shaped scoop.

3. Check for underground services before you dig

Call 0800 96 1000 (the free Dial Before You Dig service in the UK) or use the Safe Dig app if you have any doubt about what is below. Gas, electricity cables, water mains, and broadband ducting all run at depths a post hole can reach.

If you are anywhere near a boundary shared with a neighbour, confirm you are on your side first. That conversation is much easier before the spade goes in than after.

4. Drop in the post and check it is plumb

Lower the concrete post into the hole. Put a spirit level on two adjacent faces and get the bubble centred on both. Have someone hold it while you check, or lean it against a temporary prop cut from scrap timber.

Concrete posts are heavy. If you are working alone, a post-hole support spike or a bucket of loose gravel around the base makes it easier to hold position while you mix and pour.

5. Pour and tamp the postcrete

Mix one bag of postcrete per post, following the packet instructions. Tamp it firmly around the post in layers rather than pouring the whole lot in at once — tamping removes air pockets that would weaken the set.

Work quickly. Postcrete goes off fast, especially on a warm day. Top off with a slight outward slope so rainwater drains away from the post base rather than sitting against the concrete. Check plumb one final time before it stiffens.

6. Support the posts and leave to cure

Postcrete reaches a workable strength in about 20 minutes but full cure takes 24 hours. Leave the posts well alone during that window. If it is windy, brace them with a batten fixed to a temporary peg in the ground.

Resist the temptation to hang panels on a post that set only an hour ago. The load will rock it just enough to crack the concrete seal at the base, and then you have a wobbly fence from day one.

7. Drop in the gravel boards and slot the panels

With the posts solid, slot a concrete gravel board into the recesses at the base of each pair of posts. These sit at ground level and protect the bottom of the fence panels from damp soil and rot. Tamp the soil back around the outside of each post base once the boards are in.

Slide the fence panels down into the post slots from above, or fit arris rails into mortised slots if using featheredge boards. Check each panel is level before moving to the next. A string line along the top of the run is useful here — it shows instantly if a panel is sitting high or low.

When to call a handyman

Call Richard if the ground is hard clay or chalk and digging is getting nowhere, if you need more than four or five posts, or if the fence runs along a boundary that needs precise positioning. Fence jobs that look simple on paper have a habit of taking twice as long when the ground has other ideas.