What is a palisade?
A palisade is a continuous row of upright posts set closely together in the ground. Originally a defensive work, today mainly known as a boundary fence and as a low earth-retaining edge in the garden.
The historic palisade
In fortification and field defence, the palisade was for centuries the quickest way to close off a site. Pointed stakes were driven side by side, often cut off at an angle at the top and tied together with a horizontal rail or an iron band. Palisades are known from Roman military camps, medieval motte-and-bailey castles and the outworks of later fortress towns.
The palisade in the garden
In modern landscaping, a palisade is a row of round or square posts of equal or stepped height. It is used for:
- Retaining earth at a change in level, for example along a raised terrace or a border edge
- Boundaries and screening
- Shaping: a stepped palisade makes a flowing transition between two levels
Materials: pressure-treated softwood, hardwood, robinia, or precast concrete. Concrete is maintenance-free; timber looks more natural but has a finite life in the ground.
Practical rules of thumb
- Embedment depth: allow roughly one third to one half of the exposed height in the ground. A palisade standing 60 cm above ground goes 30 to 60 cm in — more the more earth it retains.
- Retaining or not. A garden palisade suits limited level changes. Above roughly a metre of retained height, or where there is loading from above (a driveway, a parked car), a designed retaining wall belongs there instead. Earth pressure is much higher than most people expect, and higher still if water builds up behind it.
- Bed the posts in compacted grit or lean concrete, not loose soil, and line them up with a taut string.
- Drainage behind the palisade is essential: a gravel trench with a perforated pipe and a filter fabric prevents water pressure and extends the life of the timber.
- Seal or cap the end grain at the top; that is where most moisture gets in.
- Check boundary lines and local rules on the height of boundary structures.
Related terms
- Fence post
- Pile dike
- Sheet piling
- Drainage
- Retaining wall
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