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Lawsons are the largest independent timber, building & fencing merchants in London and the South East of England. Established in 1921 Lawsons now have a number of branches offering the complete range of building materials.

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How to Install Fence Posts

One of the most challenging parts of installing a new fence is digging in the fence posts – most new DIYers underestimate just how deep fence their posts should go, and often buy much shorter posts than they actually need. Posts are an integral part of your fence’s structure – without proper installation, your fence will be unstable, will deteriorate faster, or even just fall over.

How Deep to Dig Your Fence Posts

To prevent your fence from tipping over, it’s important that the posts have enough leverage to withstand wind or even just the forces of gravity. As a very general rule, you should ensure that a third of the overall fence post height is underground. This means that if you are using a 4ft high fence post, your fence post will need to be 1.3ft underground. For a 6ft high fence post, 2ft will be buried underground. This also means that your fence panels and posts will not have the same height – your posts will need to be considerably higher.

Installing Your Posts

Before you start any digging, make sure that you know the location of any underground cables and pipes. You can use detectors to do this, and it can be a good idea to get in touch with your utilities suppliers just to make sure. Also, make sure you are certain about the boundaries of your property and that you will not be encroaching on your neighbours’ land.

Start your job by marking out the fence line with some string. You can use a batten the width of your fence panels to space out the posts.

Dig out the fence post holes, giving yourself enough room for 1/3 of the overall fence post length to be underground, and for around 6 inches of gravel at the bottom of the hole. Put any displaced earth on a tarp to make it easier to transport and avoid ruining your lawn.

Pour gravel unto the base of the hole to support your post and place the post in afterwards. Finally, pour in fresh concrete until it is just above ground level – this gives you some excess to trowel it smooth, sloping concrete away from the post to allow for water run-off.

Use a spirit level to check that each post is level, and prop it up using timber battens to allow the concrete to set with the post in the right position.

Leave the concrete to harden for at least an hour before adding fence posts and completing your fence.