Installation of Fence Topping Security Bracket

The bracket holds several strands of wire above the top of the fence, usually at an angle of roughly 45 degrees. Why at an angle? Anyone who grabs the top edge of the fence finds the wire right above their head or in front of their face, so they cannot swing over naturally. The bracket therefore makes the fence taller and also makes climbing awkward.

It is worth fitting where the fence itself is sound but not quite enough. If the posts lean, are rusty or loose in the ground, a bracket will not solve anything. Tensioned wire puts even more load on the posts, so repair the fence first.

Brackets differ in shape and in how they fix to the post. The post profile and the direction you want to protect usually decide the choice.

• Straight bracket: continues vertically upwards and only adds height, useful where nothing may overhang the boundary
• Single angled arm: leans outwards or inwards and is the usual choice for perimeter fences
• Y-shaped double arm: protects both sides, mainly used on sites where people must also be stopped from climbing out
• Fixing method: a slip-on bracket fits into the top of the post in place of the cap, a clamp-on bracket fixes around a round post, and a bolt-on bracket fixes to a box section post or a masonry pier

For the wire there are two options. Barbed wire is enough for everyday security and is easier to work with. Razor wire, often supplied as a coil, has sharp blades and is much harder to get past. It is risky to handle, though, and suits industrial sites better than a fence next to a path where children walk.

Both the brackets and the fixings should be hot-dip galvanised, ideally also powder coated to match the fence. Fixings without galvanising tend to rust and work loose after a few winters.

On an existing fence, the fitting itself often takes less time than the preparation. A tradesperson usually works like this:

1. Walk the whole fence and check the posts: firmness in the ground, plumb, rust and the condition of the top.
2. Repair or replace loose or damaged posts, and tighten the panel clips on panel fences.
3. Choose the bracket type to suit the post profile and agree which way the arms will lean.
4. Run a string line along the tops of the posts and set one consistent fixing height.
5. Fit the brackets by slipping them on, clamping or bolting. On masonry or concrete piers, drill holes and use suitable anchors, often resin anchors.
6. Check as you go that all brackets have the same angle and direction, and tighten each fixing straight away rather than at the end.
7. Run the line wires, anchor them at end and corner posts and tension them with wire tensioners.
8. Attach the barbed or razor wire to the line wires and brackets using tie wire or the method the manufacturer specifies.
9. Check the tension and the fixings, and bend over or cover any sharp wire ends.

This is work on a ladder above the fence line with sharp material in hand, so it is described here as a trade procedure rather than a DIY guide. Without heavy gloves, eye protection and a second person holding the wire, injuries happen very easily.

The least work is a new panel fence with solid posts, regular spacing and brackets made by the fence manufacturer for that exact profile. Fitting is then quick and the result is straight.

The job takes longer mainly with:

• An old chain link fence with rusty or crooked posts that need strengthening first
• Sloping or uneven ground, where the bracket height has to be set section by section
• Masonry piers that need drilling and anchoring, especially hollow blocks
• Many corners, changes of direction and gates, where the wire has to be terminated and re-tensioned
• Razor wire instead of barbed wire, because it has to be handled more slowly and carefully
• Poor access, for example a dense hedge or a steep bank along one side of the fence

Before fitting, find out whether you need to notify anyone or apply for permission. Rules for fences vary from place to place, and raising a fence or adding wire to a fence next to a road or footpath can bring extra requirements. Do not assume nothing is needed. Ask your local building or planning authority, which can also tell you what local plans or bylaws allow.

If the fence stands right on the boundary, an outward-leaning bracket will overhang the neighbour's land or the pavement. In practice this is solved by agreement with the neighbour, a straight bracket, or arms leaning inwards. Where the land belongs to a block of flats, changes to the fencing are decided by the owners' association or the building management.

Think about who walks past the fence. Razor wire within a child's reach or above a public footpath can injure someone, and in many countries the owner can be held responsible. Warning signs are often advisable on commercial sites.

• Brackets fitted to weak or loose posts, which start to lean under the pull of the wire
• Brackets at different heights or angles, so the wire runs crooked and the fence looks untidy
• Wire tensioned too loosely so it sags, or too tightly so it bends brackets and corner posts
• No anchoring at end and corner posts, where the strain is greatest
• Ungalvanised fixings that rust quickly
• Holes drilled too close to the edge of a masonry pier, so the anchor breaks out a piece of brickwork
• Arms leaning over someone else's land without agreement

At handover, walk the full length of the fence and check:

• All brackets are at the same height with the same angle and direction
• A bracket does not move or creak when you push it firmly with a gloved hand
• Bolts and clamps are tight and galvanised
• The posts have not leaned after tensioning, especially at corners and ends
• The wire is evenly tensioned and does not sag between posts
• Sharp wire ends are bent over or covered and nothing sticks out where people walk
• The wire does not overhang the neighbour's land or the pavement unless agreed
• No offcuts of wire or other sharp waste are left around the fence