Introduction

Let’s be honest. You don’t notice a great fence. You only notice a bad one. The one next door with posts leaning like tired soldiers. The gate that groans and drags on the ground. The neat line that’s gone wavy after one tough winter.

If you’re planning a new fence, you’re probably dreaming of the finish line—privacy, security, a crisp look. But the journey between buying the panels and enjoying that view is where things go wrong. I’ve seen it all. Let’s talk about the classic mistakes that turn a straightforward residential fence installation into a money pit and an eyesore, so you can steer clear of them.

Mistake #1: Treating Posts Like an Afterthought

Here’s the biggest secret in fencing: the part you don’t see matters most. Everyone picks out nice panels. Then they try to save £50 on posts or an afternoon’s digging. Big error.

Think of your fence like a sailing ship. The panels are the sails. The posts are the mast. If the mast isn’t buried deep and secured in bedrock-solid concrete, the first good gust will topple the whole thing. I’ve pulled up “failed” fences where the posts were barely a foot deep, just dangling in loose soil. For a proper residential fence installation, you need to go deep—often a third of the post’s length underground, set in concrete below the frost line. Skimp here, and you’re rebuilding in two years.

Mistake #2: Playing Fast and Loose With Your Boundary

This is the mistake that ends friendships and costs thousands. "I think it's about here," is a phrase that precedes disaster. You must know where your property ends. Not guess. Know.

That means checking your property deeds, and in tricky cases, getting a proper survey. The cost of a surveyor is nothing compared to the cost of moving a 40-foot fence you built on your neighbour’s land. And while you’re at it, be a good neighbour. The finished side of the fence should face outward. It’s a simple act of goodwill that pays off for decades.

Mistake #3: Hiring the Cheapest Hands, Not the Best

We’ve all done it. You search for "fencing contractor near me" and your eyes go straight to the lowest number. That quote is low for a reason. The “cowboy” crew will cut every corner: shallow holes, weak concrete, no gravel boards, and gates hung with hopes and prayers. They’re in and out in a day, leaving you with a fence that’s doomed from the start.

A true professional doesn’t just sell a fence; they engineer a structure. This is especially critical for security fencing in London, where strength and deterrent are the entire point. The right contractor talks about post depth, concrete specs, and proper fixings. The wrong one just talks about the price.

Mistake #4: Forgetting the Small Stuff That Becomes Big Stuff

Even with good posts, the details kill a fence.

• 1. Letting Wood Kiss the Dirt: Wood panels touching soil will rot. It’s not an if, it’s a when. A concrete gravel board at the base acts as a sacrificial barrier, taking the moisture so your timber doesn’t.

• 2. Building a Solid Wall in a Wind Tunnel: Solid featherboard panels are great for privacy, but they’re a sail. In an exposed garden, they need to be braced for the wind or designed with small gaps to let pressure through.

• 3. Assuming ‘New’ Means ‘Finished’: Treated timber isn’t maintenance-free. The cut ends where posts are sawn are vulnerable. A proper job includes treating those ends and advising you on a protective stain. A neglectful residential fence installation leaves the wood naked to the elements from day one.

A fence is a system. Every part has to work. From the depth of the hole to the treatment of the cut wood, skipping one step shortens its life. Doing it right the first time is the only real economy.

FAQs: Straight Answers from the Trenches

Q1: How do I really find a good contractor?

Look past the first page of search results for "fencing contractor near me." Ask for photos of completed jobs, specifically of the post bases and gate hangs. Read reviews that mention longevity. A good contractor is proud of their methods and will explain them. A cheap one just wants to talk price.

Q2: Is concrete absolutely necessary for posts?

For a fence that lasts more than a few years, yes. In soft London clay, it’s non-negotiable. Proper concrete footings anchor the posts against wind, ground movement, and frost heave. Postcrete in a bag is fine, but it has to be mixed and used in a deep, straight hole.

Q3: What’s the one thing I should never compromise on?

Post depth and setting. You can upgrade panels later. You can repaint. But if the foundations are weak, the entire fence has to come out to fix it. It’s the most expensive possible repair. Get the foundations right, and everything else is manageable.

Q4: My garden slopes. Is a straight fence impossible?

Not at all, but it requires skill. A stepped design (following the slope) is easier and uses standard panels. A racked design (where the fence runs smooth on a slope) is more complex but looks fantastic. Any contractor worth hiring should be able to show you examples of both and recommend the best for your space.

Q5: For security fencing in London, is anything different?

The principles are the same, but the specs are tougher. Posts need to be heavier and set deeper. Panels or mesh need to be stronger, often with anti-climb features. Fixings need to be tamper-proof. It’s a perfect example of why you can’t cut corners—the whole point is to be a robust deterrent, and that starts six feet underground.