Whether you're putting up a new wooden fence or updating your old one, installing fence posts is absolutely within your grasp. Here, we give you instructions for accomplishing this DIY project
The strength of a fence lies in its supporting posts. Choose 3 x 3 inch posts made from a rot-resistant wood such as cedar, or pressure-treated softwood, and set them in concrete or metal post supports. Treat the timber with wood preservative every three to four years to prevent it rotting. This technique works whether you're putting up a new fence or replacing old posts, which must be done when you spot signs of deterioration. Putting up a fence post should take you about two days.
Use a claw hammer or screwdriver to free one end of the panel (image 1). Remove metal clips and fixings. Clear soil away from the base of the panel, then free the other end. Leave the top fixing brackets until last for support.
Remove the old concrete footing. Once you have removed the fence panels, dig out the soil from around the base of each post to expose the concrete block (image 2).
Using the post as a lever, loosen the block in the hole. Tie a length of wood to the post, balance it on a pile of bricks (image 3) and use this simple lever to help you lift it.
If a new post is to go in the same spot, refill the hole and compact the soil before digging a new post hole using a trench shovel (image 1). Make it about 2 feet deep and 12 inches across.
Fill the bottom of the hole with a 4 inch layer of graded base. Stand the post on the base, check it's level with the original fence line, and pack graded base around the sides (image 2).
Use a metal spike or pole to ram the graded base in place (image 3), working the post gently back and forth to help settle the material. Aim to fill the hole to about half its depth with compacted graded base.
To test that the post is vertical, hold a level against each of its four sides (image 1). Make any adjustments as necessary, and check that the post is the right height for the fence panel.
To hold the post upright while you're concreting it in place, tack it to a temporary wood brace, fixed to a peg driven firmly into the ground (image 2). Don't attach to the side that you'll be hanging the panels on.
Fill the post hole to the top with water, then let the water drain (image 3). This will help settle the graded base and improve adhesion of the concrete. Make up post-hole concrete to a pouring consistency while the water's draining.
Pour concrete into the hole, stirring gently to remove air bubbles. Shape it around the post using a trowel so that rain can run off (image 4). Wait at least 48 hours to hang panels. Remove bracing after three weeks.
When erecting posts on a solid level surface, such as paving, use bolt-down, galvanized metal plates. These can be fixed in place relatively easily and will help to prolong the life of the wood posts by holding them off the ground.
Measure and mark the exact position of the post. Take good care to do this right, even if it takes more than once; you can't change the positions of posts once they're secured in bolt-downs. Position the base plate, marking the position of each of the corner bolt holes with a pencil (image 1).
Use a percussion or hammer drill fitted with a masonry bit to drill the bolt holes. Keep the drill upright and make sure you penetrate right through the paving into the graded base underneath (image 2).
Fill the drilled holes with mortar injection resin and insert Rawl bolts. After the recommended setting time, tighten the bolts using a wrench — the bolts will expand to fill the hole (image 3).
If you have firm, undisturbed ground, use metal spike supports. Position the spike in place and insert a "dolly," a special post-driver, into the square cup. Hit the dolly with a mallet to drive the spike into the ground. Check the angle of the spike with a level (image 4) to ensure that it is going in straight — twist the dolly handles to correct any misalignment. When the spike is in the ground, remove the dolly. Clamp the square cup around the post and tighten it up.
Excerpted from Garden Design
©Dorling Kindersley Limited 2009