There are three ways of anchoring the posts in the ground:
Mark the positions of the posts to get an idea of the final layout. It is also important to make sure the fence is straight, at right angles to the adjacent building. Use pegs to position the location of each post along the run. This will allow obstructions such as large roots from trees or shrubs to be noted before you start. Tie a string around each peg to give a picture of the straight run. This will allow you to check the straightness of the line of posts as well as obstructions due to plants.
It may be necessary to break up old concrete which was used for previous fencing. If so, use a cold chisel and hammer. It may be necessary to remove sections of paving. Make sure you lift enough to enable you to dig large enough holes.
Metal spikes are available in different sizes, suitable for different heights of fence:
A 600mm (24 inch) spike is enough for posts which will support fences up to 1.2m (4 feet) high. A 750mm (30 inch) spike is suitable to support a fence which is 1.8m (6 feet) high.
A sledgehammer is required to drive the spike into position. In order to protect the square socket at the top of the spike, which will support the post, fill the socket with a piece of surplus post before commencing with the hammering. It is important to use a spirit level on top of the socket to check that the spike is upright and in a perfect vertical position as you hammer the spike into position. Only the socket should be visible above the ground when the spike is in its final position. This may prove a time consuming job, but the durability of the fence is matched by the strength of its posts. It is therefore very important to have the spikes in the correct position before continuing.
Once ready, insert the post into the socket and secure with either clamp bolts or screwing through the holes provided in the sides of the socket. (The method used to secure the post at this stage is dependent on the type of spike used. Some spikes are sold to be secured with clamp bolts, while others have the holes for screws). If panelling is to be used, check the position of the panel before determining the exact position of the next spike. It is possible to secure the panel to the first post, supported underneath by wood, to locate the exact position of the next spike.
This type of base is suitable for securing a post to a solid surface, such as a patio. It consists of a square metal cup which supports the timber post. The rim contains holes ready made for securing the post with bolts.
The size of hole - The size of hole required is dependent on the height of the post it will be supporting. Generally, bury one quarter of the post to provide a firm foundation.
If for example, your finished fence needs to be 6 feet (1.8 m) high, use 8 feet (2.4m) posts. One quarter of 8 feet is 2 feet. Therefore dig a 2 feet deep hole to take the 8 feet high post which will give 6 feet above the ground as the visible post. Make sure the hole is wide enough to support hardcore and concrete around the bottom and sides of the post. There is a tool available called a post hole auger, which can be hired to help with the digging of the hole (see )
The auger is twisted as it drives into the ground, removing and loosening the ground. It looks like a large corkscrew on a very long handle. You will need to stop every so often to pull out the auger in order to remove the contents of the hole before proceeding again until the correct depth has been reached. The post hole auger is less effective in very stony ground.
Securing the posts - Once you have reached the correct depth, you are ready to secure the post into position. Fill the base of the hole with a bedding of hardcore, this will enable the post to have some drainage away from the base of the post (vital if the post is wooden, to prevent rotting at the base). Support the post into position with battens and stakes. If the post is concrete, stabalise its position with guy ropes. Check the vertical position of the post with a spirit level, before filling the hole with concrete - use a mixture of 1:2:3 = cement:sand:aggregate.
Push the end of a batten into the hole to make sure there are no air pockets and there is a firm even mix all around the base. When the hole has been filled, it is worth building the concrete up, just above ground level, and slope it away from the post. This will deter water running down the post and into the base of the post. The concrete should take approximately one week to harden. It is advisable to leave the supports around the post or other temporary struts to secure the positioning against any movement during this time.
Securing end posts for chain link fencing - It is essential to anchor the end posts securely, particularly when using chain link fencing. Chain link fencing requires the end posts to resist the tension of the straining wires at the top and bottom of the fencing. A notched end post is advised as this can be supported by a pre-cast strut. Secure the notched end post in the ground.
Dig a channel along the line of the fence, taking it a little further along from the position of the bottom of the strut. Make the channel approximately 18 inches (450mm) deep. Fill the bottom of the channel with hardcore and wedge a brick under the strut to force the strut tightly into the notched end post. Fill the channel with concrete and allow the area to thoroughly harden, before attempting to attach the straining wires. Use a special bolt and cleat to adjust the tension. When putting on the wire netting, bolt a stretcher bar to the cleats. Threadle galvanised wire through the pre-drilled holes and use it to tie the straining wire to the posts.
If the fence adjoins a masonry wall, the first post needs to be attached to the wall using three expanding masonry bolts. Use a washer to prevent the wood being crushed at the surface. As with all posts, use a spirit level to check that the post is in a horizontal position before securing. Drill holes at the correct positions and drive in some packing at each location. This will allow for minor adjustments when tightening the bolts to get the best fit between the wooden post and wall.
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