The most reliable way to stop squirrels using your fence post caps is to remove the flat, comfortable surface they sit on. Replace flat caps with pointed or pyramid ones, cut back anything within jumping distance, and where a post still gets used, fit a short length of irregular-height deterrent spikes across the top of the cap. Squirrels treat posts as perches, lookouts and launch pads, so a post that is awkward to stand on is a post they tend to skip.
Why do squirrels keep sitting on my fence post caps?
A flat post cap is a stable platform at a useful height. From it a squirrel can see the garden, watch for cats and foxes, eat what it has taken from your feeder, and jump to the next perch. Posts are also often the last solid point before a squirrel crosses onto a shed, bird table or roofline.
Squirrels also gnaw. Timber caps with soft edges or a split can get chewed, so a cap used as a regular perch may start to look damaged. If you are seeing both squirrels on the posts and wear on the wood, the fix is the same: make the cap less useful.
If squirrels are running the length of the fence rather than just sitting on posts, read how to stop squirrels climbing your fence as well. Posts are only part of the route.
What is the free or cheap fix to try first?
Start with changes that cost little or nothing.
- Swap flat caps for pointed or pyramid ones. A steep slope gives a squirrel nothing to sit on. Most are cheap timber or plastic and fit in a few minutes with exterior glue or a nail. They won't stop a determined squirrel from running past, but they remove the resting spot.
- Cut back overhanging branches. Squirrels jump a long way, so try to leave a gap of around 2m between tree limbs and your fence or posts where you can. Check first whether the tree is protected or belongs to a neighbour.
- Move the thing they are after. If the posts lead to a bird feeder, relocating the feeder away from fences, sheds and branches does more than any cap. Our guide to stopping squirrels getting to your bird feeder covers pole baffles and placement distances.
- Clear fallen food. Spilled seed and nuts under the fence keep squirrels coming back to the same route.
These steps work best together. A pointed cap alone, with a feeder two metres away and an overhanging branch, will still be used.
When are spikes worth fitting on post caps?
Spikes are worth it when you cannot change the layout: the fence runs beside a tree, the posts are stone or concrete with flat caps, or squirrels have already made a habit of using one particular post.
The design matters. Flat spikes of one height leave gaps a squirrel can step across or balance between. ThornGuard strips use an irregular three-height pattern of 12mm, 22mm and 36mm, so there is no level line of tips to walk along. That staggered layout is what stops climbing animals as well as birds. It is the same reason cheap flat spikes tend to fail on fence tops.
The strip is humane. It makes the cap uncomfortable to stand on and does not injure the animal. No deterrent is guaranteed on every squirrel, so combine it with the habitat changes above.
How do I fit spikes to a post cap?
- Check for nests first. Look over the post and cap for any bird nest or nesting activity. If a nest is active, leave it alone and fit later. Disturbing an active nest is against UK wildlife law.
- Measure the cap. Note its width and length, and how far the cap overhangs the post. You want spikes to cover the full top surface, with no flat corner left to perch on.
- Cut to size. The strip can be cut across its four sections. Cut one length per post to match the cap, and keep offcuts for the end posts. Our guide to cutting bird spikes to size covers cutting and splitting lengthways.
- Fold if the post is the target. The strip bends four ways and folds along its length, so it can wrap the top and sides of a post rather than only sitting flat. This matters on narrow posts, where a squirrel will try to grip the edge.
- Fix it. On timber caps, use the screws supplied. Pre-drill a small pilot hole so you don't split the wood. Cable ties, also in every pack, can hold the strip to the post below the cap.
- Check for gaps. Press on each corner. A squirrel can use any bare corner or edge as a foothold.
The 4m pack (10 strips) and the 8m pack (20 strips) usually cover more posts than you would expect, because each cap only needs a short length. There is a step-by-step guide on the fitting page.
What if I can't drill into the cap?
Stone, ceramic, concrete and powder-coated metal caps are easy to crack or mark. For these, use ThornGuard's separate waterproof adhesive pads instead of screws. Clean the surface, let it dry fully, press the strip down firmly and give it time to bond before rain.
For more detail on adhesives and which surfaces suit them, see how to fix bird spikes without drilling.
What about free-standing posts with no fence?
On a lone post, such as a feeder post, sign post or washing-line post, a spike strip on top does not stop a squirrel climbing the shaft. Squirrels can climb timber easily, so you need a smooth barrier on the post itself. A pole baffle fitted below the feeder is the usual answer, and it works best when nothing is within jumping range. Use spikes on the cap only as a second layer.
Common questions
Will squirrels chew through post caps?
They can gnaw timber, especially soft or already-damaged wood. A metal or hard plastic cap resists this better, and spikes on top make the cap an unpleasant place to sit and chew. If you see heavy chewing, check for a food source nearby.
How do I stop squirrels getting on my roof from the fence posts?
Break the route: remove branches, fit deterrents on posts and fence tops, and keep a gap between fence and roofline. Our guide to stopping squirrels getting on your roof covers each access point.
Are spikes on fence posts legal in the UK?
Yes, on your own property, provided they are fitted to deter and not to harm, and you avoid any active nests. See our guide on whether bird spikes are legal in the UK for the rules.
Originally published at ThornGuard
