Choosing fencing tools
The list above is what exists. This is how to decide which of it you actually need, what separates a tool worth keeping from one that ends up at the back of a drawer.
Whose boundary is it
Before anything is dug, establish where the boundary is and who owns the fence. The title deeds and the Land Registry plan show the general line, and a T mark on a plan indicates which side has responsibility for that boundary.
The practical point is that posts and their concrete need to sit on your side of the line, and a fence built over a boundary can be required to come down. A conversation with the neighbour before the first hole is dug prevents nearly every fencing dispute there is.
- Check the deeds
- The Land Registry plan and any T marks showing which side owns which boundary.
- Posts on your side
- Including the concrete. A post centred on the line is a post partly on their land.
- Talk to the neighbour first
- Before digging. It prevents nearly every fencing dispute that arises.
- Height limits apply
- Generally 2 metres, or 1 metre next to a highway, before planning permission.
Post depth and spacing
A post goes in to roughly a quarter to a third of its above ground height, so a 1.8 metre fence needs about 600mm in the ground and a 2.4 metre post. Shortening that is the commonest reason a fence leans within a few years.
Spacing is set by the panel: 1.83 metre panels need posts at 1.83 metre centres plus the post width, which is why measuring from the same reference each time matters. Errors accumulate and arrive as a panel that will not fit at the end of the run.
- A quarter to a third
- Of the above ground height. A 1.8 metre fence wants about 600mm in the ground.
- Deeper in exposed positions
- Wind load is what pushes a fence over, and it acts on the whole panel area.
- Spacing by panel width
- Plus the post thickness. Measure from the same reference, not post to post.
- Set the ends first
- Then a line between them, then the intermediate posts to that line.
Concrete, postcrete or nothing
Postcrete is the fast option: pour water in, add the mix, and it sets in minutes. Convenient, and it can trap water around the post if it forms a collar with no drainage, which accelerates rot at exactly the point where the post fails.
The alternative is gravel in the bottom for drainage with concrete above, finished proud and sloped away so water runs off rather than pooling. Or a metal post spike or bolt down shoe, which keeps the timber out of the ground entirely.
- Gravel in the bottom
- So water drains away from the post end rather than sitting against it.
- Finish concrete proud and sloped
- Water runs off. A dished top holds a puddle against the post permanently.
- Postcrete is fast, not better
- It sets in minutes and it can form a water trapping collar. Drainage still matters.
- Metal spikes keep timber clear
- A spike or bolt down shoe means the post never touches the ground at all.
Where a post actually rots
Not at the bottom, but at ground level, where the timber cycles between wet and dry and has oxygen available. That is the zone where fungal decay works fastest, and it is why a post snaps at the surface with sound timber above and below.
So use pressure treated timber with a use class rated for ground contact, treat any cut end with preservative because the cut exposes untreated heartwood, and keep the concrete or soil sloped away rather than banked up against the post.
- It rots at ground level
- Wet, dry and oxygen together. That is why posts snap at the surface.
- Use class matters
- Ground contact rated timber, not general treated. The treatment depth differs.
- Treat every cut end
- Cutting exposes untreated heartwood. Preservative on the cut, before it goes in.
- Slope soil away
- Soil banked against a post holds moisture in the exact failure zone.
What is under the fence line
Fence lines follow boundaries, and boundaries are where service runs, drains and soakaways often sit. A 600mm hole is deep enough to reach a shallow water main, a gas service or a drain, and post holes are dug with force rather than care.
So sweep the line with a detector, check for inspection covers and meter positions, and dig the first few centimetres carefully. Where a service is found, a post can usually be moved a little without affecting the fence at all.
- Sweep the line first
- A cable detector along the whole run before any hole is started.
- 600mm reaches things
- Shallow water mains, gas services and drains all sit at that depth or above.
- Look for covers and meters
- They tell you where the runs go. A meter at the boundary means a service crosses it.
- Move the post
- A post shifted 200mm changes nothing about the fence and avoids the service.
Frequently asked questions
- What tools do I need to put up a fence?
- A post hole digger or auger, a spade, a post level, a string line, a tamping bar, a spirit level, a saw and a cordless drill. Add a cable detector for the line, postcrete or concrete, and gravel for drainage in the bottom of each hole.
- How deep should fence posts go?
- Roughly a quarter to a third of the above ground height, so a 1.8 metre fence needs about 600mm in the ground and therefore a 2.4 metre post. Deeper in exposed positions, since wind load on the panel area is what pushes a fence over.
- How far apart should fence posts be?
- Set by the panel width plus the post thickness, so 1.83 metre panels need posts at that spacing plus the post. Set the two end posts first, run a line between them, and position the intermediate posts to that line rather than measuring post to post.
- Is postcrete better than concrete for fence posts?
- It is faster rather than better. Postcrete sets in minutes, which is genuinely useful, and it can form a collar that traps water against the post. Either way, put gravel in the bottom for drainage and finish the top proud and sloped away.
- Why do fence posts rot at the bottom?
- They rot at ground level rather than at the bottom, because that zone cycles between wet and dry with oxygen available, which is where fungal decay works fastest. That is why a post snaps at the surface with sound timber above and below it.
- Do I need to treat cut fence posts?
- Yes. Pressure treatment penetrates from the outside, so cutting a post exposes untreated heartwood at the cut. An end cut buried in the ground without preservative is a direct route for decay into the middle of the post.
- How high can I build a fence without planning permission?
- Generally 2 metres, or 1 metre where it adjoins a highway used by vehicles, though there are exceptions for listed buildings, conservation areas and covenants. Check with the local authority if the fence is anywhere near those limits.
- Whose fence is it and who repairs it?
- The title deeds and Land Registry plan show the boundary, and a T mark on a plan indicates which side has responsibility for it. Posts and their concrete must sit on your own side of the line, and a fence over a boundary can be required to come down.
