UNIQUE Group is a professional concrete mixing equipment manufacturers in China.

Most fences suffer from two problems - they either

by:UNIQUE      2020-10-13

The fence is approximately 1.2m high - large enough to provide a clear division without being obtrusive. Reinforced concrete posts - the type normally sold for chain link fencing - are cemented into the ground at regular intervals. Vertical battens are bolted through the holes in the posts to provide supports for the horizontal boards which make up the main panelling. The horizontal timbers are arranged in a 'board on board' pattern - alternative boards are fixed to opposite sides of the battens so that both sides of the fence look equally neat. The boards overlap each other slightly to give maximum privacy but still allow a small amount of light to shine through and fall on border plants.

PLANNING CONSIDERATIONS

Before you order any materials, check with the local planning authority which planning regulations, if any, apply to the erection of fences in your area. In the UK, planning permission is not needed for a garden fence under 2m high. Fences erected on the front boundary, on the other hand, require planning permission if they are over 1m high, so you will either have to go through the planning procedure, or alternatively build a lower version of your fence.

Plan exactly where you want the fence to stand and measure out it's complete run from start to finish. If you want the fence to turn at an angle - near the corner of a garden for instance - make a note of the length of each straight section as well.

Bear in mind that the fence posts themselves must stand inside the boundary of your property. The exact boundary lines should be marked on the title deeds of your home; otherwise consult your local planning authority which will be able to show you the most up-to-date plans.

To calculate how many posts you need, simply divide the total run into 2.5m sections (the distance between each post). You are almost certain to find that you have a small amount left over. If so, you will have to order some short horizontal timbers and erect an extra panel at the end of each straight section. If the gap is particularly small - say less than half a metre - it may be better to make up the distance by planning two shorter equal-sized panels rather than one.

The posts are 125mm x 125mm thick and 1.87m long (600mm is buried underground). Ask for reinforced 'strainer' posts intended for chain-link fencing ('spacer' posts will not do). If you can't find these, any other square-sectioned, flat-sided (not tapered or grooved) concrete posts will be suitable provided that they have at least three bolt holes.

Try to get the wood for the vertical support battens and horizontal boarding cut to length where you buy it; this will save a great deal of time and effort cutting it to size on site. The vertical battens are made up from lengths of 50mm x 50mm sawn softwood - each batten is one metre long. One batten is needed for each end post and two for intermediate corner posts.

The horizontal boards are made up from lengths of 150mm x 25mm sawn softwood. The ordinary panels use boards 2.4m long, although shorter boards may be needed to complete the run. Seven lengths are needed for each panel.

The wood must be treated with preservative to protect it from decay. Some stockists can offer timber which has been pressure-treated although this adds to the cost. Otherwise, you will have to buy a suitable timber preservative and treat the timber yourself. Ordinary creosote can be used or a proprietary coloured timber preservative.

To fix the vertical battens to the concrete posts you will need a number of 250mm M10 (3/4 inch) coach bolts plus nuts and flat washers.

The horizontal boards can either be nailed or screwed to the vertical battens. Which technique you use is largely a matter or personal preference - screws give a stronger fixing but they are more expensive and more work. Remember also that if you use screws you will need to pre-drill the timber and if you use an electric drill you will need to be within easy reach of a power point or risk using a long trailing extension. All of the fixings should be rust-proof and 38mm long. Nails can be galvanised - screws can be either zinc-plated or brass. Reckon four fixings per board. If you decide to use screw fixings you can speed things up by using a combination bit. This drills a pilot hole for the shank/thread and countersink for the head in one drilling operation. If your fence turns a corner you will need some extra 63mm screws plus some wallplugs to fit.

Bedding the posts firmly into the ground calls for a quantity of hardcore - small stones, rubble and broken bricks - and some concrete. You may be able to find enough hardcore lying around your garden. If not, try to find a demolition site or look locally for a firm that is willing to supply hardcore in such small quantities. For the concrete, use a mixture of Portland cement and 13mm all-in aggregate (sand and gravel mixed). To give you an idea of how much to order, to set in ten posts would take a 25kg bag of cement plus 125kg of all-in ballast.

SETTING OUT

Accurate setting out is essential if you want the post holes to be in the right places. Start by marking out each straight section with wooden pegs and a nylon line.

Position a peg at each outside corner exactly in line with one side of the fence and stretch a nylon line between the two. Next measure out and mark the positions of all the post holes by removing small divots with your spade. There should be a distance of 2460mm between each post - measured centre to centre. To make sure all the spacings are equal, keep your measure parallel to the nylon line.

Remove the wooden pegs and guidelines before digging post holes which should be 200mm square and 600mm deep; square off the sides with your spade. Check that each hole is centred correctly by double checking the distance from one hole to the next.

Once all the post holes are dug, the next step is to bolt the vertical battens to the posts. If the battens are not already cut to length, do so at this stage. Then drill holes in them for the bolts. You will find it easier and quicker to mark and drill one batten accurately, then use this as a template for marking out the rest. Rest the template batten against the side of one of the posts, 50mm from the top. Mark the bolt hole positions on the timber by pushing a pencil through each of the holes in turn. Remove the template batten and drill a 10mm diameter hole through each of the marks. Then mark and drill all the rest of the battens using the template as a guide.

Now bolt the battens to the posts. Bear in mind that each intermediate post should have two battens - one bolted to each side - while end and corner posts have only one batten which is bolted to the inside of the post. Push the end bolt into position and fit a washer and nut to the other end. Then tighten all the nuts evenly until the timber is held firmly in place. If the holes in the posts are slightly too small to pass the bolts through, open them out with a 12mm masonry bit.

For a neat appearance, make sure that the bolt heads on end and corner posts are all facing outwards.

If your fence has to turn a 90 degree corner, an extra batten should be attached to the corner post at right angles to the other batten. The easiest way to do this, since there are no available holes on that side of the post, is to use plastic wallplugs as used for making fixings in the masonry. Isolate each of the corner posts and lay them flat with the side in which you want the fixings uppermost.

Taking the first post, start by drilling four equally spaced pilot holes down the centre of its extra batten. Transfer these marks to the post, then with a masonry bit drill holes for the plugs. You may be unlucky enough to hit one of the horizontal steel reinforcing stirrups buried in the post. If so, move a little further up or down from the mark and drill a fresh hole. Fit the plus and screw the batten into place. Repeat the procedure on all the other corner posts.

If your corner turns at an angle other than 90 degrees, you can either plane one of the battens to the correct angle before fixing or sandwich a length of tilting fillet (normally used for the edges of flat roofs) between the batten and the corner post.

When all the battens are drilled and fixed, the posts are ready to be erected. Move them - preferably with the help of an assistant and a wheelbarrow - and lay them on the ground next to the relevant holes.

ERECTING THE FENCE POSTS

The most difficult task when erecting a fence is to keep the posts in a straight line and make sure all the component parts (in this case the horizontal boards) are level.

The easiest way to do this is to 'build a line', which also avoids the possibility of a creeping error - an error that gets progressively worse as you work from one component to the next attached one, making a small mistake each time.

Before you start, make sure that all of the hardcore is to hand by depositing a small pile by each hole. Erect the two end posts first. If your fence turns a corner it is best to work on each straight section separately. Place each post in the middle of the hole and shovel hardcore around the outside. Stamp the hardcore down firmly with your foot or with the end of a length of batten until you have built it up to a depth of about 300mm. Check that the post is exactly upright by placing a spirit level or a plumbline against all four sides.

The end posts should stand up on their own while you erect the rest of the posts. If not, prop them up temporarily with a few lengths of heavy timber.

Now stretch guidelines between the two posts. Position one line across the top and one on either side about 150mm lower down. The lines will act as an accurate guide when you erect each of the intermediate posts.

Push scraps of timber of uniform thickness between the lines and the post. This will give you enough clearance to position the other posts without pushing the guidelines out of true.

All the intermediate posts can now be positioned and hardcore added as above. The upper guideline keeps the tops of each post level, while the two other lines ensure that the post is vertical from front to back; all you have to do is make sure that the sides are trued up with the spirit level.

Once all the posts are in position, mix up a batch of concrete on a nearby slab or piece of board. Unless you have a lot of posts to set in, it should be easy enough to do by hand and not worth hiring a mixer. Use a bucket as a measure to ensure you get the right mix of cement to ballast - one bucketful of cement to five of ballast.

Turn the dry ingredients together with a spade until the colour is uniform. Form the mix into a ring and slowly add water - about half a bucketful to begin with - to the centre. Turn the dry ingredients into the water, taking care that it doesn't escape. When all the water is absorbed, turn the whole pile over to ensure an even mix. If it is too dry, form a new circle and add more water to the centre as before.

Concrete is heavy, so although you can carry it on a shovel it is a lot easier to load it into a wheelbarrow. Pour concrete around the posts until it reaches a height just below ground level. Agitate the concrete briskly with the end of a batten to make sure that the mix settles correctly and all air bubbles are removed. Check once again that each of the posts is correctly aligned; it should be possible to make small adjustments by pulling the post in the required direction. Leave the concrete to set hard - normally at least four to six hours.

FIXING THE BOARDING

Once the posts are in position, the horizontal boarding can be nailed or screwed into position. Before you start, shovel loose earth around the base of each post to cover the concrete slab.

If the ground is flat or only slightly sloping fixing the boarding is quite straighforward. If the boards have not been cut to length, do so at this stage. The technique is to fix all of the top boards first and then move down the fence to the next board, and so on until you reach the bottom. The two side lines can be used as a guide to keep all the boards level and should be moved down the fence as you progress.

You have a clear choice as to how you position the boarding. In the design shown here each panel is 'reversed' so that the top board on every second panel is on a different side of the fence. But you can fix the boards so that each panel is identical with the top board on the same side each time.

Position all of the top boards level with the top of the battens. Each subsequent board should overlap the others by about 8mm. The natural curves in the boards will make it virtually impossible to maintain this distance with absolute accuracy, so aim for a rough average. If you are using screws each board should be predrilled before fixing using a combination bit. Use two fixings at the end of each board.

On sloping ground, you should try to 'step' the boards. Start at the lowest end of the wall and fix all the boards in that section before you move onto the next. All you have to do to 'step' the boarding neatly is to make sure that the top board in each section is positioned correctly: it should be aligned with the top of the batten on the lower post and then levelled accurately. If the ground slopes to any great degree between the posts, it will not be possible to fit the bottom boards in place because of the angle. Don't be tempted to try and trim these boards off to match the angle of the ground. It is hard work and the result looks untidy. Instead, excavate the slope for a short distance to form a stepped terrace, so that you can fit in a straight bottom board. Any large gaps left around the feet of the posts can be levelled off with topsoil once the fence is completed.

PROOFING THE TIMBER

If you use ordinary softwood outdoors it will quickly succumb to rot or insect attack and decay. It is possible to buy timber which is specially treated for use outdoors. There are various commercial processes which inject ordinary softwood under pressure with a fluid which protects it against both fungus attack and wood-boring insects.

This adds to the cost of the wood, and such timber isn't available from all stockists. The alternative is to buy ordinary boards and treat them yourself - after they have been cut to size. There are several fluids you can use.

Creosote is a well known traditional wood preservative based on tar and oil. The main disadvantage is that it stains the wood a dark, unattractive colour. Also, the protective effect lasts for only two or three years, after which a new treatment must be given.

There are also several solvent-based chemical preservatives. Although these are often considerably more expensive, the protection is more effective and they are available in a wide range of shades - so the proofed timber will look more attractive.

Whichever preservative you choose its effectiveness depends on how well it penetrates the wood, so it is important to apply it thoroughly. There are two methods - using a brush or soaking.

If you apply it with a brush, take care to treat all sides of the timber equally. You should give at least a couple of coats to ensure thorough penetration. The cut ends of the wood expose the absorbent end grain, and these will require even more coats to ensure that they are properly protected.

Soaking ensures a consistent and deeper penetration of the preservative. The disadvantage of this larger method is that you require a larger quantity of the fluid and a suitable trough to hold it.

The easiest way to arrange a trough is to buy a sheet of heavy-duty polythene, large enough to enclose the timber you want it to treat. Lay the boards on it, then fold the sides up. Keep them in place with the concrete posts, spare pieces of timber or bricks.

Pour in the preservative and leave it for as long as possible to penetrate the wood. Turn the boards from time to time to ensure that all sides are reached. (WARNING: Timber preservatives may contain harmful chemicals. Read the makers' instructions carefully and keep pets and children away from the fluid or timber while still wet.)

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