If you have a fencing project in mind it is worth knowing how to plan a fence for the wind conditions you face. Wind conditions vary with where you live and the local conditions. Once you’ve determined the wind conditions, there are various things to consider when you plan a fence to cope with them.
Where do you live?
In very general terms the LEAST windy areas of Britain are within an area bounded by a curved line drawn from London, Southampton, Cardiff and Manchester – the shaded area in the map.
In this area basic average wind speed is around 7 to 9 mph.
Outside this area basic average speeds go up to 8 to 10 mph, and in some areas the averages are nearly 15mph. Eight out of the ten highest averages are in Scotland.
To see a detailed map have a look at the Met Office pages on the windiest places in Britain.
Of course, storms and much higher winds can affect any part of the UK. Coastal and western areas are usually the most badly hit by storms. The UK has seen three major storms in January 2018 alone – Storm Eleanor brought gusts of up to 90mph.
Plan a fence for the wind conditions locally
Local conditions have a real impact. In rural, open situations wind speeds tend to be higher than in urban environments. In build up areas the friction of the buildings slows the wind.
Elevation is a factor too. Higher land generally sees stronger winds than lowland areas – the highest winds ever recorded in the UK were at Cairngorm Summit.
Any obstruction such as buildings or trees can cause wind to blow in gusts. This can create turbulent local effects. Gusts can easily double the basic wind speeds you experience. They are unpredictable and usually of short duration.
Some structures provide protection from the wind and create quite sheltered spots.
So if you have moved into a new home it is worth taking a little time to become familiar with the local effects so you can plan a fence for the wind conditions you are likely to experience.
Once you’ve determined whether your garden is sheltered or likely to experience windier conditions it’s time to plan the fence itself.
What type of fence is best for a windy garden?
Most domestic fences are lap panels between posts. These present a large surface area to the wind which means there will be large forces on the fence. In fact any kind of design where boards are very close together will act like a sail. It will catch the wind and place a lot of force on the whole fence.
A fence design which allows the wind to pass through to some degree will experience less wind force and so will withstand stronger winds better.
A real alternative to lap panels is hurdle fencing. It allows more wind through while still giving you plenty of privacy. The picture below shows Hazel Hurdle fencing (available from Primrose, click here for details https://www.primrose.co.uk/hazel-hurdles-fencing-panel-182m-182m-6ft-6ft-papillon-p-1728.html)
Other options include slatted fence designs, palisade fences or using trellis.
Get the height right
Wind speeds increase quickly with height, so the height of your fence plays a big role in how much wind it is exposed to.
If you are keen to have a high fence in a windier spot, how about a trellis topper? This adds height but allows wind to pass through. In this way you take some of the stress off, at the very place where that stress is strongest.
Gardeners often want to protect their plants with a fence. But, just like other structures, the fence itself will create both shelter and turbulence beyond it.
For example, a normal lap panel fence will shelter an area downwind of about five or six times the fence height. But, as the wind tumbles over the fence, it creates turbulence beyond that protected area. There the wind can be surprisingly damaging. So, when you plan the height of your fence, consider where its shelter will end and the turbulence might begin, and set your fence height (or your planting area) accordingly.
Don’t forget your post anchors!
If you plan a fence to cope with the wind, then make sure it is anchored properly too. FenceFins™ post anchors cope really well with windy conditions. They cope better with strong winds than metal spike fittings. And the added bonus is that they get stronger and stronger over the years, as the ground settles. All with no need for concrete!
You can read more about how we tested FenceFins™ and see a couple of videos that show how strong they are here.