How to erect a fence
Difficult rating: Medium
These tasks may be tricky so will suit you if you're experienced in DIY, or simply love a challenge.
Before you get started on any of our 'how to' guides, please take a moment to read through our DIY safety tips.
1. Choosing the right type of fence
First take a look at the size and design of fencing that suits your garden and your needs. There's a wide range to choose from:
- Closeboard fencing - closeboard is made up of overlapping vertical boards of timber. This is the strongest and heaviest panel. It gives you complete privacy and is ideal for boundary fencing.
- Overlap fencing - this is made from overlapping horizontal timber boards. It's a cheaper fence that offers high levels of privacy.
- Palisade - you get both visibility and good security from this traditional picket-type fence.
- Trellis - use trellis on its own as open screen fencing or as a decorative panel on top of a solid fence.
One of the things neighbours argue about most is the boundary between their properties - where it lies and who's responsible for its upkeep. If you're unsure, check your title deeds. You can get a copy from the Land Registry. 'T marks' on the plan point in the direction of the owner who has to maintain the wall, fence or hedge (fig. 1).
2. Choosing the right posts
- Decide if you want wooden or concrete posts - there are pros and cons for both. And do you set them in concrete or use post supports? Post supports are metal containers dug into or fixed onto the ground (figs. 2 and 3).
- Concrete posts ensure you have a good strong fence, but they do need a fair bit of work to put up.
- Wooden posts are easier handle. But as they're buried in the ground, there's a slightly higher risk that they'll rot.
- Metal post supports deal with some of these problems. And they'll help you put up a fence relatively quickly (figs. 2 and 3)
Check your fence complies with planning rules - ring your local council for advice. You need planning permission for fences over 2m high.
3. Calculating the post lengths
- Decide on the height of your fence and you can work out the length of the posts to buy.
- If you're burying wooden posts in concrete you'll need 8ft (2.4m) posts for a 6ft (1.8m) fence - i.e. your posts are 2ft (0.6m) longer than the fence height.
- If you use post spikes (fig. 3) or bolt-down post sockets (fig. 2), you'll need 6ft posts for a 6ft fence.
- If using post spikes, check for pipes and electric cables in the ground as they go down to a depth of 18in.
- Use 4in x 4in posts for fences of 6ft and over and 3in x 3in posts for anything under 6ft.
4. Calculating the number of panels
- Fence panels are nearly always 6ft (1.8m) wide.
- Measure the length of the area being fenced. Divide the length by the width of the panel - example: for a 36ft fence, 36ft ÷ 6ft = 6 panels.
- You'll also need the same number of gravel boards to place at the bottom of each panel.
- Add one more fence post to the number of panels needed so you have enough posts to support both ends of the fence.
5. Preparing for the job
- Before you start, clear away vegetation and treat the area with weedkiller.
- Most fence panels and wooden posts are pre-treated to prevent rot and insect attack. But it's a good idea to treat any sawn end with an all-purpose wood preservative.
- Use a string line and pegs to mark out where the fence is going (fig. 4). Mark the position of the first post.
6. Using metal spikes as supports
- First it's important to check the location of any water pipes or power cables. If you're unsure, talk to your local council.
- Make a pilot hole with a metal spike, rod or bar. Place a piece of scrap timber into the socket of the metal spike. With a sledgehammer drive the spike into the pilot hole until the top of the socket is level with the ground.
- Stones and hard ground can make it tough to drive the post in exactly vertically. Use a spirit level as you hammer the post in to check it's staying vertical.
- Buy 600mm spikes for 4ft fences and 750mm spikes for anything higher.
- Alternatively you can bolt sockets with flat square bases (bolt-down post sockets) into concrete (fig. 2).
7. Fixing your posts in concrete
- The holes for your posts should be three times as wide as the post. So for a 4in post the hole will be at least 12in wide.
- The holes should be 2ft deep.
- Following your string line, dig a hole for each post with a post spade or a post-hole borer (which can be hired).
- So you don't have to lift a heavy panel into position when you move to the next post, use a wooden batten cut to 6ft as a guide.
- With the post in place, ram broken brick or stone hardcore into the base of the hole to support the end of the post.
- You can mix your concrete fresh but it's easier to use a bespoke concrete mix such as Postcrete.
- Normally you half-fill the hole with water and pour the powder mix on top, but check the bag instructions.
- The concrete should be just above ground level. Trowel the surface smooth, sloping the concrete away from the post to let water run off (fig. 7).
- Check the post is vertical on two adjacent sides with a spirit level. Then prop it up with one or two timber battens to hold it in position while the concrete sets (fig. 7).
- Premixed concrete sets in a few minutes, so work quickly! Go along the fence line, making sure the posts are aligned with each other as well as being upright.
- Leave the concrete to harden for at least an hour before attaching the fencing panels.
8. Fixing the fence panels
- You'll want to keep the fencing panels off the ground to prevent them rotting. Do this by adding treated gravel boards along the bottom or leaving a gap of at least 100mm under each panel.
- Screw the panels to the posts using two or three U-shaped post clips per post (fig. 5).
- Use stainless steel screws to prevent rusting.
- If you're using wooden posts, when the panels are all in place trim the tops of each post so they're all the same height. Then screw on a post cap (drill a hole in the cap first to prevent splitting - fig. 6).
9. Fencing the sloping site
- If your fence is on a sloping area, still keep the panels horizontal. Fill the angled gap under each panel by cutting a gravel board to fit it or building a low retaining wall directly under the fence.
- This will make your fence look 'natural' and level, especially if it runs alongside your house, garage or an outbuilding.
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