A Good Fence Needs Good Foundations
No matter how good the quality of the fencing materials, if the foundations are poor then the overall fence quality will be reduced. Over time the posts will start to lean and eventually the fence could fall completely.
Whoever does the hard installation work, one very important element often overlooked or skimped on are the fence foundations. Good foundations are hard work to achieve and cost money to produce.
Planning
Plan your fence foundations as carefully as you plan your fence.
The Fence Foundations.
Usually when we refer to the foundations of a fence we are referring to the way in which the fence posts are secured into the ground.
To make sure these foundations are secure and successfully hold the fence in place, make sure the following points are followed:
Whoever does the hard installation work, one very important element often overlooked or skimped on are the fence foundations. Good foundations are hard work to achieve and cost money to produce.
Planning
Plan your fence foundations as carefully as you plan your fence.
The Fence Foundations.
Usually when we refer to the foundations of a fence we are referring to the way in which the fence posts are secured into the ground.
To make sure these foundations are secure and successfully hold the fence in place, make sure the following points are followed:
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| Digging a fence post hole using a shuvholer |
- The post holes need to be the correct depth. This is a minimum of 600mm (2ft) and in most cases the hole depth will be deeper. We talk more about this later.
- Longer or heavy duty posts should be used in areas exposed to wind or soft ground conditions.
- The post hole depth is not the only concern when digging the hole but the width and sides also follow guidelines. Make sure the hole is not a large crater but is either square or round and has straight sides. If installing the fence yourself, the correct tools for the job are important and make the task much easier. A hole created for a fence post will be much better if a Shuvholer and fencing spade are used rather than a traditional shovel.
- When the hole is the correct depth and post is the correct height then you're ready to secure the post. Remember, don’t scrimp on the concrete. If using ballast and cement make sure you use enough (60kg per post for a 1.8m high panel fence is a good recommendation), make sure the mix is correct, or consider using a premixed product generally known as Postcrete. Postcrete will ensure the correct strength of mix an reduces the labour element as no mixing is required, just add water to the hole and then add the Postcrete mix. It also sets rapidly in approx. 5 minutes.
How Deep Should Fence Posts Be?
The depth of a fence post is critical for stability and longevity. A general rule of thumb is that one-third of the post’s total length should be below ground. For example, if you have a 1,800 mm (6 ft) post, aim for a hole about 600 mm (24 in) deep.
Always Check Manufacturer Guidance
Before you start, always check what the fencing company or manufacturer recommends regarding post depth. Many state the one-third rule, which means one-third of the post should be in the ground. This rule can be loosely followed for domestic applications, but heavier or commercial fencing may require deeper settings.
Practical Depth Guide
Remember to add a minimum of 50mm (2 inches) of gravel at the bottom of the prepared hole to help drainage as this helps to prevent the post rotting. It will also help to get the post at the correct height when installing.
Finally, using fully pressure treated timber is a must. Ask the supplier if the fence is covered by a guarantee or service life. Long term and respectable guarantees usually show that the timber materials and fence posts have been kiln dried before treatment. Wet or high moisture content timber is impossible to impregnate successfully unless correctly dried first and these products will not carry a long term guarantee.
Following some of these simple steps should ensure your investment in a new fence will save you money and hard work in the future and give a long term investment.
For more information and How to install a fence, see Jacksons Fencing video of installing a fence post.
Blog originally written in early 2014 and updated in August 2025
Before you start, always check what the fencing company or manufacturer recommends regarding post depth. Many state the one-third rule, which means one-third of the post should be in the ground. This rule can be loosely followed for domestic applications, but heavier or commercial fencing may require deeper settings.
Practical Depth Guide
- Low garden fences (900–1,200 mm / 3–4 ft): 450–600 mm (18–24 in) deep
- Standard fences (1,800 mm / 6 ft): 600–750 mm (24–30 in) deep
- Tall or heavy fences (2,400 mm / 8 ft or more): 900 mm (36 in) or deeper
Finally, using fully pressure treated timber is a must. Ask the supplier if the fence is covered by a guarantee or service life. Long term and respectable guarantees usually show that the timber materials and fence posts have been kiln dried before treatment. Wet or high moisture content timber is impossible to impregnate successfully unless correctly dried first and these products will not carry a long term guarantee.
Following some of these simple steps should ensure your investment in a new fence will save you money and hard work in the future and give a long term investment.
 |
| Adding Gravel at the bottom of the hole aids drainage |
For more information and How to install a fence, see Jacksons Fencing video of installing a fence post.
Blog originally written in early 2014 and updated in August 2025
