How Deep Should a Fence Post Be Set?

Getting Your Fence Posts Right: 25+ Years of UK Timber Experience

Here at UK Timber, we've been helping customers build lasting fences for over a century, and if there's one question that comes up time and again, it's this: "How deep should I dig my fence post holes?"

After decades of supplying timber across the UK - from the clay soils of the Midlands where our main sawmill operates, to the sandy coastal regions - we've learned that there's no one-size-fits-all answer. But there are some solid principles we always share with our customers.

The Foundation Rule (With Real-World Adjustments)

The old carpenter's rule is simple enough: one-third of your total post length should go underground. So for a 1.8m garden fence, you'd typically dig 60cm deep. But here's what 100+ years in the timber business has taught us - this rule needs adjusting for British conditions.

In our experience delivering thousands of fence posts across the UK, we've seen what works and what doesn't. Those picture-perfect fence installations you see in our delivery photos? They follow these depth guidelines we've developed:

Standard Garden Fencing (1.8m panels): 65-75cm deep Tall Privacy Fencing (2m+): 80-90cm deep

Agricultural/Stock Fencing: 90cm+ (livestock can be surprisingly determined!)

Why British Soil Matters More Than You Think

Operating sawmills across the UK, we deliver to every type of ground condition imaginable. Our crane drivers - who've been installing fence posts for decades - always tell customers about the "soil factor":

Clay Soils (common across the Midlands): These expand and contract dramatically. We recommend going 10cm deeper than standard and always using concrete. The clay around our Northamptonshire mill has taught us this the hard way!

Sandy/Coastal Soils: Less stable, so we typically advise 15cm deeper than the standard rule, especially for our customers in Cornwall and Norfolk.

Rocky Ground: Sometimes you simply can't dig the full depth. In these cases, we recommend our concrete fence posts or steel spike bases - products we've developed specifically for challenging UK terrain.

Weather Reality Check

Let's be honest about British weather - it's unpredictable and often harsh. After supplying fencing materials through countless storms (remember the 2018 Beast from the East?), we've learned that wind loading is serious business.

For exposed sites - hilltops, coastal areas, or anywhere that catches the prevailing wind - we always recommend:

• Adding 15cm to standard depth recommendations
• Using concrete setting (we stock rapid-set options)
• Considering our engineered fence posts for extreme conditions

The UK Timber Installation Method

Here's how we recommend setting posts, based on what we've seen work consistently across thousands of installations:

1. Dig 15cm wider than your post - this gives you working room and ensures proper concrete coverage
2. Add 10cm of hardcore/gravel at the bottom - crucial for drainage in our wet climate
3. Set your post and check it's plumb - our delivery drivers always carry a spirit level for this reason
4. Concrete or not? For anything over 1.5m high, we always recommend concrete. For lower decorative fencing, well-compacted soil can work

What We've Learned From Customer Callbacks

Nobody likes a callback, but they've taught us valuable lessons. The most common fence failures we see are:

• Posts set too shallow in sandy soil (especially holiday properties near the coast)
• No concrete used in clay areas that experience frost heave
• Poor drainage leading to premature post rot (even with our pressure-treated posts)

That's why we developed our fence post installation guide - it's based on real failures and real successes from over a century of timber supply.

Our Honest Recommendation

Look, we could sell you the most expensive engineered posts and concrete, but often that's overkill. For most UK garden fencing using our pressure-treated softwood posts:

• Dig 70cm deep for 1.8m fencing
• Use concrete in clay or exposed locations
• Don't forget the gravel base for drainage
• Buy quality posts to start with (ours are pressure-treated and graded for fencing use)

Why Choose UK Timber Posts?

When you're going to the effort of digging proper holes, it makes sense to use posts that'll last. Our pressure-treated fence posts are sourced from our own mills and come with the quality guarantee you'd expect from a company that's been in timber for over 100 years.

Plus, with our own fleet of crane vehicles, we can deliver your posts exactly where you need them - no dragging heavy timber around your garden.

Ready to start your fencing project? Browse our full range of fence posts or give our experienced team a call on 01536 267107. We've probably dealt with soil conditions exactly like yours before.