Dig-in or bolt-down palisade posts?
Dig-in is stronger and cheaper and should be the default. Bolt-down is for concrete you cannot break into — and it needs the right thunder bolts for the post height.
Every palisade post we sell comes as dig-in or bolt-down, and it is worth a minute's thought because changing your mind afterwards means either breaking out concrete or cutting posts down.
Dig-in
The default, and the better fence. The post is supplied longer than the fence height — roughly 550mm to 700mm extra depending on height — and that length goes into a concreted hole. The result carries load through the ground rather than through a handful of anchors, which matters when somebody drives into it or leans a ladder against it.
It is also cheaper: no base plates, no anchors, and no need for a sound concrete slab to bolt to.
Bolt-down
Posts are cut to the fence height and base-plated, then anchored to existing concrete. You choose this when you cannot dig — a concrete yard you do not want to break out, a deck, a rooftop, a slab with services under it, or a site where the fence may need to come up again.
Two things to be aware of. The anchors carry everything, so the concrete they go into has to be sound and thick enough — this is a genuine engineering question on a 2.4m or 3.0m fence, not a detail. And the bolts are an extra: they are not supplied with the posts.
Thunder bolt sizing
If you are base-plating, match the anchor to the post height. This is AA's guide rather than a specification — you are responsible for the fixings you install and the concrete you install them into.
Thunder bolt by post height
| Post height | Bolt size |
|---|---|
| 1.2m to 1.5m | M10 x 75 |
| 1.8m to 2.0m | M10 x 100 |
| 2.4m | M12 x 100 |
| 3.0m | M12 x 130 |
Anchors
Mixing the two
There is no problem running dig-in along most of a boundary and switching to bolt-down where it crosses a concrete apron or a service run. Order the posts you need for each section — they are stocked both ways at every height, and the rails, pales and fittings are identical either way.
Posts at every height
Gates are the same choice
Palisade gate posts come dig-in as standard, supplied longer than the gate height. Choose base-plated and we cut the posts and plate them. Gate posts take considerably more load than fence posts — a 6m double leaf hanging off them all day — so if there is any doubt about the slab, dig them in.
Products covered in this guide
Frequently asked questions
- Should palisade posts be dug in or bolted down?
Dig in wherever you can. It is stronger, because the load goes through the ground rather than a few anchors, and it is cheaper because there are no base plates or bolts to buy. Bolt-down is for existing concrete you cannot or do not want to break into.
- What size thunder bolts do palisade posts need?
As a guide: M10 x 75 for 1.2m to 1.5m posts, M10 x 100 for 1.8m to 2.0m, M12 x 100 for 2.4m and M12 x 130 for 3.0m. The concrete has to be sound enough to take them, and responsibility for the fixings sits with whoever installs them.
- Are base plate bolts supplied with palisade posts?
No — thunder bolts are ordered separately. The same applies to base-plated gate posts.