Why Bristol fences fail on the west side first

There is a pattern to fence failure here, and it is not random. The run that goes first is usually the one facing south west, and the thing that actually failed is usually a post rather than a panel.

This covers the wind, the ground under the post, exposed boundaries against sheltered ones, whether a run is worth repairing, and what a buildings policy will genuinely pay for. Published figures where we have them, and a plain note where we do not.

The wind arrives from the same direction every time

Fetch is the distance wind travels over open water with nothing to slow it down, which is why a south westerly here lands harder than the same system delivers inland.

So a boundary does not weather evenly. The south west facing run takes the load and most of the driven rain, and it dries slowest, while the same fence on the sheltered side of the garden can outlast it by years. When somebody rings about one panel we look at the whole run, because the failure that has happened is often the first of several.

What the big storms actually did here

We have written walls and boundaries there rather than fences on purpose. We could not find a Bristol news report about fence damage specifically from either storm, and we are not going to invent one. What happens to timber in that wind is our own trade experience, and we would rather label it as that.

High ground and valley floor are two different jobs

Bristol is not flat, and it does not weather as one place. A few markers, because they change what a boundary needs.

• Clifton Down runs from about 79 metres up to 101 metres at the Observatory, with the Avon Gorge open to the west. Exposed ground, and a run up there carries far more load than the same fence lower down. Detail on our Clifton page.
• Horfield Common is one of the highest points in the city, and boundaries on that ground take the full south westerly.
• Gloucester Road sits at the low point of a valley cut by the culverted Cutlers Mill and Horfield brooks, with streets rising on both sides. Sheltered, and damp.
• The River Malago drops from 155 metres on Dundry Hill to roughly 10 metres at the New Cut, so the gardens either side of it in Bedminster and Southville sit on valley floor.
• Fishponds sits on the broadly flat Frome valley floor, the sheltered end of our patch for wind.

We have not verified precise elevations for Kingswood, Bedminster or Fishponds and we are not going to make them up, so we are generalising: ridge and common are exposed, valley floor is sheltered, and the difference lands on what the posts have to do rather than on the panel you choose.

A sheltered garden is not an easy garden, mind. Valley floor holds water, and standing water round the base of a post finishes more fences here than wind does. Exposed ground argues for concrete posts and deeper settings because of the load. Wet ground argues for the same posts for a different reason.

What is under the post matters as much as what is above it

Digging a post hole is not the same job street to street here, and the geology is published rather than guesswork.

The British Geological Survey flags the Lias Group as containing swelling and shrinking smectite clay, medium volume change potential with some high layers. Ground that moves seasonally works a post loose over years, which is how a post feels solid in February and rocks in your hand in August.

Alluvium floors the Avon and Frome valleys, typically under 5 metres deep. Soft, wet, and no use to a post relying on the ground to grip it.

Carboniferous Limestone forms the Avon Gorge at Clifton, and Pennant Sandstone underlies much of east Bristol. Both are a slower dig, and both hold a post well once it is in. That is a cost that belongs in the quote rather than in a surprise on the day.

Kingswood is its own case, and there the ground is the story rather than the wind. It sits within a Coal Authority development high risk area, its mining history means gardens have occasionally opened up, and shafts at Siston Hill Colliery reached around 170 metres. So we look at what a post hole is going into before digging it, and stop and say so if the ground looks wrong.

It is nearly always the post, not the panel

The panel is what you find on the lawn. The post is what failed. Two ways it goes, and they need different answers.

The post snaps at ground level. Timber rots where it sits wet, so a post gives way at the waterline while the top of it still looks sound. Push the run gently before you ring anybody: if it moves at the base and the timber sounds soft, that post was at the end of its life and the storm only finished it.

The post moves in the ground. Nothing has broken. The setting has failed, because the concrete was shallow, or absent, or the hole was never wide enough. A post that leans and springs back is telling you the same thing as a snapped one, more politely.

Either way the panel is often reusable and the post is not. That is the repair or replace line.

Four things that actually keep a fence standing

• Depth and concrete. A post carries the whole run either side of it, and the load in a south westerly is a lever rather than a push. Concreted properly it flexes and holds. Set shallow, it works loose season by season and goes on the first bad night.
• Gravel boards. A concrete or treated timber board along the bottom, taking the contact with the ground so the panel sits clear of standing water. Cheapest item here and on wet ground it does the most. Detail on our posts, concrete and gravel boards page.
• Hit and miss panels. Boards fixed alternately to each side of the rails with a gap between them, so wind passes through instead of pushing on a solid sail. On exposed ground that is the difference between a fence that flexes and one that levers its own posts out.
• The posts either side of the one that went. Same age, set on the same day by the same person, same weather since. Checking them takes two minutes, and it stops you paying twice.

Repair or replace

The answer depends on the posts, and it is a five minute check rather than a judgement call. If the posts are sound and it is boards, rails or one panel that has gone, repair it. If a post has snapped or is moving, that post needs replacing whether the panel does or not. If most of a run is at that stage, doing the lot at once costs less than doing it one post at a time across three winters.

For what it costs, the only Bristol figures published by a third party are Checkatrade's.

A range you can check beats a range we assert. Storm work is on our fence repairs and storm damage page.

What your insurance will and will not pay for

Most UK buildings policies exclude storm damage to fences and gates. That is the ordinary position rather than a loophole, and it catches people out every winter, because the same policy covers the rest of the property in the same storm.

The cases usually covered are narrower:

• A vehicle running into it.
• Deliberate damage, normally with a crime reference number from the police.
• Fire.
• A tree coming down onto it.

Check your own wording rather than taking ours. Policies differ, and the exclusion is usually written plainly in the buildings section under storm.

Whatever the answer, photograph it before anything is moved. A wide shot of the whole run, a close shot of the break, and something in frame for scale. That takes a minute, and once the panels are stacked against the shed it is the only evidence that exists.

The short version

• The south west facing run goes first, because that is where the weather comes from.
• It is the post, not the panel, in almost every case we are called to.
• Exposed ground and wet ground point at the same fix: better posts, set deeper, with a gravel board.
• Photograph the damage before it is cleared, whatever your policy says.

We work weekdays 8am to 6pm and Saturday mornings 8am to 1pm. Storm damage gets priority inside those hours, and anything sent through the form gets a callback the next working morning.