Fencing Materials and Techniques

Materials

There are many different types of materials which can be used for sand dune fencing, and the best choice for any situation will depend on the factors detailed below. Often the simplest and cheapest materials are also the best. Most sand dune fencing has a relatively short life, compared to fencing elsewhere, and is liable to be either buried or exposed as sand levels change. The more sophisticated the design and materials, the more work is likely to be involved in repairing or removing it.

Use and intended life

1. If the fence is required only for sand trapping, and will hopefully be buried within a few months, the cheapest, degradable material such as brushwood is the most suitable. Where brushwood is not available, the next best material to use is the cheapest obtainable synthetic material, supported on non-preserved posts and mild steel wire. A life of a year is usually acceptable, as if the fence has not become buried in that time, it possibly never will.
2. Some sand trap fences are designed to trap sand seasonally, the sand then being eroded back seawards during winter storms, or blown into eroded dune areas by winds from a different direction. The aim of this ‘piggy bank’ fencing is that it remains in position for as many years as possible, the sand accumulating and eroding on an annual cycle. In this case the fencing should be as permanent as possible, usually built of tanalised posts and 4.00mm mild steel wire, supporting chestnut paling or strong svnthetic fabric. Brushwood can be used, either alone or attached to post and wire fencing, but will only have a life of about two years before it breaks up and needs replacing. Timber slat fencing (see below) is also suitable. Two examples of this type of use are shown below. See also here.
   
3. For access control purposes, fences need to be suitable for the anticipated public pressure. Normally, such fences will be needed to last for several years, before changing sand levels affect them. However, in areas recently restored with planting, sand build-up may be rapid, so that access control fences need lifting or replacing after only one season.
   A whole range of materials can be used for access control fences. Brushwood or chestnut paling are suitable where their ability to trap sand is not going to cause problems. Chestnut paling is useful because it can be lifted and re-used. It can also be erected with a gap at the bottom so that it does not trap sand.
4. Wave barrier fencing is probably the most difficult to build, as it is so vulnerable to destruction by the sea. Brushwood only, set in holes about 600mm (2′) deep, can be effective, and if this is lost, at least there is no high material cost wasted (although labour costs for handling this material may be high). Otherwise, a post and chestnut paling fence is probably the best type to use.

Vandalism

A problem closely related to access is that of vandalism. Particularly vulnerable is any material which can be removed for beach bonfires. Losses of brushwood can be reduced by attaching it to post and wire fences (see below). The deeper posts are buried in the sand, the more difficult it is to remove them. Chestnut paling needs to be kept in good repair to discourage people helping themselves to any loose pieces.

Where vandalism is a more serious problem, chestnut paling and other types of wooden fencing are unlikely to last long, and post and wire fencing will be necessary, with strong synthetic material such as ‘Wyretex’ (see below) for sand trapping. Thicker wire, of 3.15 or 4.00mm diameter, is more difficult to cut than thinner wire. It is dangerous to cut any wires while they are under tension, and particularly high tensile wire. High tensile 3.15mm wire retains its springiness, even when persistently climbed on.

Good layout of fences and paths, with clear signing, greatly reduces damage caused by people inadvertently finding themselves on the wrong side of a fence, and causing damage when they climb over or break through. For more details on access control fencing, see Chapter 6 – Access Management.

Labour, access and availability of materials

1. Brushwood fencing is much more labour intensive than other types of fencing, because of the time required to cut, gather and transport the material, as well as the time taken to erect the fence. However, where brushwood is being cut anyway as part of management within the dune system, or is available by the lorry load from elsewhere, the time factor is less significant. It is a job suitable for volunteers, as many hands can be employed, and the work is not as skilled as some other types of fencing.
2. On remote sites, and those where brushwood is not available locally, other material must be used. Synthetic netting or pre-fabricated timber slat fencing can be brought in, and is quick to erect, so making the best use of labour which is only available for a short time, such as on a volunteer project. On remote sites, it may be important to use the most lightweight material available.
3. Labour to maintain fences is also an important factor. Where no maintenance is likely, either ‘cheap’ materials such as brushwood, or low-maintenance materials such as timber slat fencing are most suitable. Chestnut paling usually requires regular maintenance;
4. Strained wire and chestnut paling fences can be erected quite quickly by a few skilled people. In places where machinery can get access, a mechanical post driver can be used which speeds up the job considerably.

Appearance

Sand dunes are amongst the most natural habitats in Britain, and even those which are damaged and degraded by erosion remain essentially wild and unmanaged places.

1. Fencing should not mar this natural appearance. Most sand fencing which is well-built and maintained is acceptable, given that repair of the dunes is necessary. Effective sand-trap fencing rapidly becomes filled with sand, and access control fences need not be an eyesore. Fencing that is poorly maintained or vandalised, or sand-trap fencing that is not functioning will always be an intrusive element.
2. Fencing that is neat and tidy in appearance is more likely to be respected by the public than fencing which is poorly constructed or badly maintained.
3. Sand trap fencing which follows a smooth line, for example along the front of the foredunes, and is of even quality and porosity throughout will trap sand evenly, making a long even dune which matches the natural sweep of the beachline. Such dunes are less likely to erode, because there is nothing to create turbulence. Fencing of a patchy uneven quality will create patchy results.

Length of fence

Strained wire fences are not usually worth erecting over lengths of less than about 10m, because the main effort, time and expense goes into erecting the straining posts, which can be used over a much greater distance. Therefore, synthetic fabrics which need supporting on tensioned wires are better suited to longer fence lines. Chestnut paling should not be highly tensioned, and for most fences on sand dunes, straining posts are not required (see below). Wire for supporting brushwood does not have to be highly strained, and therefore can be erected over short distances without straining posts.

Techniques

There are two basic types of post and wire fence used on sand dunes:

1. Strained wire fences. These fences are usually over 10m in length, and are used either for access control, or to support synthetic netting for trapping sand. The fence has a straining post at either end, which takes the strain of the wire. The intermediate posts strengthen and stiffen the fence, and hold the wires at the correct height. When constructing the fence, wire strainers such as ‘Monkey’ strainers are used at the straining post to pull the wire tight. Either mild steel wire or high tensile steel wire can be used, the latter requiring stronger straining posts. The wire is fastened off at the straining posts, but at the intermediates is held by a staple driven far enough to just touch, but not grip the wire.
2. Non-strained wire fences. These are short lengths of wire and brushwood or chestnut paling fence. No straining posts are built, so the wire cannot be tightly strained but is merely tensioned by hand, and fastened to each post with a staple which grips the wire (though does not distort it). The strain is thus held equally at each post. Monkev strainers are not used. The posts are normally spaced closer together than are the intermediate posts of strained fences.

Straining posts

The following method should be sufficient for most sand trap fences. If necessary the post can be strengthened by fitting a ‘Spanish windlass’ (see below). Where long lengths of strained fencing are being constructed, one of the designs of strainer shown for access control should be used.

Use a post about l 25-150mm diameter (5-6″) and long enough for at least 1 m (3′) to be below the Surface. Dig out a large stepped hole before placing the post. Then nail anchor plates, about 1m (3′) long, in opposite pairs as shown. Backfill the hole, treading it to pack the sand firmly. If there is water nearby, it can be sprinkled on every 50mm (2″) layer, to settle the sand.

Other posts

The usual method of erecting posts is to dig a hole 760-900mm (2′-3′) deep, using a shuv-holer. Place the post in position, and then backfill, tamping the sand with an upturned post. The tamper can be used to ‘collapse’ the side of the hole against the post, then the upper part is filled by shovelling.

Hole digging is easy enough in deep sand, but can be a slow job on sites where there is a buried beach line of shingle which is hard to dig through. Do not put posts in less than 760mm (2′) deep, or they may be easily loosened and removed by vandals.

Alternatively, posts can be melled into sand with a ‘Drivall’ or mell. This is quicker than digging, but does not usually get the post as deep or as firm in the sand as when the post is set in a dug hole. Where access by machine is possible, posts can be driven in quickly and firmly by a tractor mounted post driver.

Wire and fastening

Wire is sold by weight, and therefore the thicker the wire the higher the cost. Weight for weight, mild steel and high tensile steel wire are a similar price. Never use barbed wire in sand dune fencing, as it can be dangerous if it becomes partly buried.

For long lengths of fence supporting synthetic netting, and for access control fencing, high tensile wire can be used. This has the advantage over mild steel wire of greater springiness, and retains its tension under changing temperatures and if people climb on it. It needs properly constructed straining posts, and must be unrolled and handled with care, as weak points can develop if the wire is kinked. The 3.15mm diameter size has been found satisfactory in use. On sand dunes, it can be strained at least 100m between straining posts, taking it around turning posts as necessary. Much longer strains are possible in firm soils. The best method of fastening high tensile wire to straining posts is to use spiral fence connectors, which grip the wire as shown. These are available from major fencing suppliers. Note that only one staple is needed, to locate the wire at the correct height.

Mild steel wire can also be used, and is suitable for straining over lengths of up to 50m between straining posts. The size normally used is 3.15mm, which is reasonably easy to handle, but needs wire cutters or a hacksaw to cut, so discouraging petty vandalism. The 4.00mm size can be used as a greater deterrent. but is more expensive and slightly more awkward to erect because of its relative non-pliability.

If spiral fence connectors are not used, the wire should be fastened off at the straining post as shown.

Do not use more staples than necessary; usually two per wire should be enough. All stapling damages the wire galvanising, so reducing wire life, and adds to the non-degradable content of the fence. Staples can be dangerous if they work free and lie loose in the sand.

Always hammer staples at an angle, so the two points enter different grains in the timber. This lessens the chance of the wood splitting. At straining posts, hammer the staple so that it grips the wire, but not so far that the wire is severely distorted and the staple head flattened. At intermediate posts, the staple serves only to locate the wire at the correct height. It is therefore sufficient to hammer the staple so that it just touches, but does not grip the wire. This holds the wire so that it does not wear against the staple when moved by the wind, but allows it to move if for example a weight is leant against the fence.

Brushwood fencing

Brushwood fencing is most suited to areas having a plentiful supply of cuttings from nearby scrub thickets or forestry plantations. You can use any sort of brush as long as it retains its density. Sea buckthorn is ideal, provided you cut it in autumn and leave it to die over the winter. Otherwise it may resprout when ‘planted’ in fences. All brushwood fences are tempting sources of firewood, but sea buckthorn is too thorny and hard to burn to attract much interest. Conifer thinnings burn easily and are more likely to be taken. Spruces and firs are better than pines and larches because they have a flatter spread of branches and so remain bushy even when the needles have dropped off. Pines and larches, with their curved or twisted branches, become thin and ragged once they have dried.

Bacon (1975, p8) recommends Norway spruce (Picea abies) as ideal, followed by Sitka spruce (P sitchensis), Douglas fir (Pseudofsuga menziesii) and western hemlock (Tsuga heterophylla) in that order.

Another good source of brushwood material are unsold Christmas trees (usually Picea abies). Their value drops to nothing on Christmas Eve each year, and if you find a garden centre or shop which has over-purchased, the manager may be glad to get rid of an embarrassing surplus. A further advantage is that cut trees are packed ‘flat’ for delivery from the plantations, thus onward transport is fairly economical. The flattened shape is also useful when fence-building. In some places sand dune managers have also asked members of the public to bring along their discarded trees after Christmas. Although this may not amount to very much in terms of brushwood, it can be a good publicity exercise to encourage interest from local people.

Virtually any brushwood can be used. The important factor is the time taken to gather and transport it (see below). Loppings from roadside trees or parks that have anyway to be put on a lorry for disposal may be worth obtaining, especially where this helps the authority concerned by saving on disposal costs.

Most brushwood has a life of about two years before it starts to break up, which is ample time to allow for sand build-up. Buckthorn lasts about five years, and is therefore better used for access control fencing, or for erosion control on inland blowout, where there is no sand supply and the aim is to prevent further sand loss and allow natural regeneration to take place.

Collecting and bundling brushwood

Collecting and bundling brushwood is a good job for winter, when felling is likely to be underway and when sheltered work is at a premium. Ideally, the plantation should contain the desirable species, be accessible for transport in all weathers, have been brashed within the past year and certainly no more than three years previously (the branches become brittle with age), have an abundance of brashings and a minimum of honeysuckle, bramble and thorn for efficient collection, and be as close to the work site as possible to reduce transport costs. The last consideration is the least important, up to a distance of 20 miles (32km), since loading is more time-consuming than transport within this distance (Bacon, 1975, p8).

Once you find the plantation, you may be able to persuade the landowner, forester and gamekeeper to let you collect brushwood free of charge since clearance reduces fire risks, improves access for future forestry work and may be used to open up the forest floor for pheasants (you may have to leave brushwood around the plantation edge, for cover).

Bundling the brushwood reduces the work time and effort by two thirds compared with transporting it loose. Lay out lengths of twine (old baler twine is ideal and may be available free from farms) and place branches across them, with the butt ends one way, so that the tied strings will be at the balance points of the bundles. Grade the branches roughly into two sizes, or as required. Use one string per bundle for branches up to 1.5m (5′) long, two strings for 1.5-3m (5′-10′) long branches. Brash over 3m (10′) long is not worth the effort in handling. Tie the string with a slip knot, pull it really tight and secure it with a half-hitch.

You can leave bundles in the woods for up to twelve months (three months for brash with needles on) provided you prop them against a tree trunk so that they keep dry. Bundles propped at the edge of the wood or under a light canopy may deteriorate due to vegetation growing up through them.

Dutch fencing

The original Dutch fencing was of cut reeds or willows, being the only material available in the fenlands of Holland, which was set into a trench dug in the sand. This technique is still used. In Britain, any available brushwood can be used, such as Christmas trees, conifer brashings, loppings of birch, alder etc. Sturdy, well-branched material can be set singly into holes dug in a row in the sand. The holes should be 450-900mm (1.5-3′) deep, depending on the height of the brushwood, and the rapidity with which sand is expected to accumulate. Brushwood used within the range of wave action should be set as deeply as possible.

Thinner, less sturdy material should be bundled and tied with baler twine, the bundles being of a size to make the brushwood stay upright, and dense enough to trap sand. The bundles can be set in holes, or in a trench 750-900mm (2.5-3′) deep. Space the holes, or the brushwood within the trench, so that the porosity of the fence is as even as possible along its length. Normally the holes or bundles should be 300-450mm (1-1.5′) apart. Make sure that there is plenty of brush at the base of the fence, or the wind will simply scour underneath. If necessary shorten the bare part of tile main stem. Christmas trees are well branched to the base, and where sand accumulation is likely to be rapid, can be set about 450mm (1.5′) deep. Some species may resprout, particularly willow, poplar and sea buckthorn. This can be useful on badly eroded sites where any growing vegetation is beneficial, but care should be taken that undesirable species do not spread into valuable parts of the dune habitat. Sea buckthorn is a particular menace, and cuttings should be left for several months before use in fencing.

Advantages:

Cheap
Biodegradable
Can be used for sand trapping and access control
Suitable for voluntary labour

Disadvantages:

Brushwood can be vandalised
Bulky to transport
Some material may sprout (though this can be useful)

Post and wire fencing with brushwood added

This is more durable than Dutch fencing, as the wire holds the brushwood in place against wind and wave action, and discourages vandalism. All sorts of brushwood can be used, including material which may be too short to use in Dutch fencing. Post and wire with brushwood is recommended where fencing is needed for both access control and sand trapping, and where the fence may need to stay in position for several seasons. It should not be necessary to use post and wire where sand is expected to accumulate within a few months.

Post and wire with brushwood is more time consuming to erect than Dutch fencing, and is more expensive in materials. It is also a nuisance to clear up if it becomes damaged or undermined. Whether or not wire is necessary depends very much on the location of the site, and the amount of supervision and management it receives. Remote sites, or those which are heavily used for recreation but are not constantly managed are likely to need the insurance of post and wire. By contrast, on some parts of the Sefton coast, Merseyside, the move is away from using post and wire, as it has been found that with sufficient labour and supplies of brushwood it is possible to quickly place effective Dutch fencing. If done over the winter, this should be mainly buried by the start of the busy summer season. The area is closely wardened throughout the year.

Advantages:

Reasonably durable
Discourages vandalism
Access control use

Disadvantages:

Slow to build
Cost of post and wire
Not biodegradable

Several designs have been used:

1. Brushwood between parallel wires. This design can be varied to suit local conditions and materials. Bacon (1975, p7) recommends the type shown below, which has been used on National Trust sites on the Northumberland coast. You can use old net stakes and baling wire for economy, since even if the fences start to deteriorate in four to six months they should be well buried by that time.
   Knock the posts in securely. Using a stake or crowbar, pitch holes in two rows, 150mm (6″) apart, to take the brushwood. Make the holes 300-600mm (1-2′) apart within the rows, and at least 300mm (1′) deep. Push sturdy 1.8-2.4m (6-8′) branches into the holes, with their curvature towards the centre. Secure them with 2.50mm wire, running each side of the double row from post to post, about 900mm (3′) above ground level. Place intermediate ties at 900mm (3′) intervals between the posts. Trim off the tops of the branches as necessary. This not only looks neat, but means that the fence should fill to the top, with no line of odd protruding branches remaining to mark its position.
   Variations on this design, which have worked well on a number of work sites, include using 2.1m (7′) unpointed posts for greater security in soft sand, using shorter branches to make a somewhat lower fence where brushwood is scarce, placing the wires near the top of the fence, and twisting the wires together with a wrecking bar to tighten them around the brushwood.
   
   This latter technique is done to tension the wires after the fence is complete. However, it can also be done at more frequent intervals while the fence is being built, to hold the brushwood securely in position and deter firewood gatherers. Some slack must be left at each end of the wire, which is taken up as the wire is twisted. This does tend to make a rather gappy fence, so additional material may need to be added, tied to the horizontal wires.
2. ‘Woven’ brushwood fences. This design uses more stakes and wire but less brushwood than the fence described above, and is best employed where brushwood is scarce and where stakes can be finned securely so that the wire can be tensioned.
   
   Such fences should last at least a year. Care must be taken to weave the brushwood closely so that an even cover is made. This can be quite difficult, especially with sparse material such as pine or larch. Very twiggy material such as birch is probably the best.
3. Tied brushwood fences. For Christmas trees and other bushy material it is easier to omit the middle wire and attach each piece by tying its ‘trunk’ or main stem to the top and bottom wires. A spacing of 200-300mm (8-12″) between stems is usually sufficient. The quickest method of attachment is to use sack ties, twisted into place with a wire tying tool or ratchet screwdriver. Otherwise, just attach with short lengths of baling wire, twisted to tighten.

Post-and-rail fences with brushwood added

These are suitable for use on machair-edge restoration work.

These fences are most easily made and last longest if sawn tanalised fence posts and rails are used.

Brushwood-and-stake fencing

These low barriers have been used successfully at Holkham National Nature Reserve, Norfolk, both to trap sand and to divert people onto an adjacent boardwalk.

Fences are positioned at right angles to the walkway across a wide gap in the fixed dunes. They are placed in pairs, each fence about 1m (3′) from its partner. This discourages people from walking over the low fences and creates strips of protected sand in which plants can grow.

With pairs of fences installed al 4.5-9m (15-30′) intervals along the gap, most people are dissuaded from walking in the fenced area and keep to the boardwalk.

The fences are quick and easy to make using cuttings and fallen brush from nearby plantations. Brushwood is laid flat on the sand and held with rough stakes driven in at an angle. No digging is required and the turf remains relativelv undisturbed. Where the brushwood has convenient branches these can be woven over the stakes to help hold the fences more tightly together.

Chestnut paling

With the increasing cost of transporting brushwood, chestnut paling is becoming more competitive as a material for sand trapping. It is quicker to erect than wire and brushwood fencing, so is useful where labour is limited. It is more effective than brushwood for sites which are subject to wave action.

The type commonly used is 1.07m (3″) high, with 75mm (3″) pales and 75mm (3″) gaps, joined with three double strands of wire. It is supplied in 9.2m (l0yd) lengths. This should be supported on 2m (6’6″) posts of approximately 100mm (4″) diameter, set 1m (3′) in the sand. Space the posts at 1.8m (6′) or 3m (10′) intervals, depending on the site and pressure of use. The paling should not be tightly strained, as the wire used to bind the pales is not suitable for tensioning.

There is also no satisfactory way of securing the wires if the paling is pulled tightly, as in order to stop the wires slipping at the staple, the staple has to be driven in so far that the wire is damaged. Use one staple per strand at each post, hammered to grip but not distort the wires. First attach the paling to the end post, then pull by hand at the next post and staple, or gently use a crowbar or spade as a lever, as shown. Do not over-do this, or the pale will break. The pales should remain vertical and parallel to the posts. If possible arrange it so that joins in the paling coincide with a post. If not, simply join the lengths by twisting the free ends around the first pale of the next length, to imitate the method of manufacture. Do not twist the wire more than necessary or it will snap.

Slabwood fencing

Fencing using slabwood is not recommended, as the usual width of 75-125mm (5-7″) is too wide, in effect making the fence too solid, and causing scour at the base and between the slabs. It is also vulnerable to firewood-gathering.

Timber slat fencing

The Countryside Commission for Scotland have devised a system of timber slat panels, using slats 75mm (3″) by 8mm, with 75mm (3″) spacing. This method is useful on sites where brushwood is not available, as the panels can be assembled in a workshop and quickly erected on site. Full details are given in their information sheet 5.2.5 (CCS, 1982).

Synthetic materials

A wide range of synthetic fabrics have been tried for sand trapping. Note the following:

1. Most of the materials require attachment to a strained wire fence. This can be of either mild steel or high tensile steel wire, depending on the length of run, and the ability to erect secure straining posts.
2. Materials vary in their porosity, and thus in the shape of the dune they create. However, all create a uniform profile along their length, because of the uniformity of product.
3. Materials vary in their durability against waves, wind, ultra-violet light and vandalism. The estimated time required for sand filling must be weighed against the estimated life of the product. Degradability is a useful quality once sand-trapping is complete.
4. All materials are light and easy to handle, compared to brushwood or timber slat fencing.

Advantages:

Lightweight
Useful for remote sites
Quick to erect
Creates uniform dune

Disadvantages:

Expensive
Difficult to achieve durability against wind and vandalism, with degradability

A summary of the available materials follows:

Enkamat

This is a flexible three-dimensional matting, originally designed for laying on banks of ditches, roadsides and reservoirs, to stabilise the surface and allow vegetation to become established. It has also been found to be useful as a vertical fence, for sand trapping. Enkamat is made of filaments of black nylon welded together to form a tough mat with 95% free space. It is available in various thicknesses and widths, with or without a backing material on the ‘flat’ side. The type which appears to be the most effective is 7020, which is 20mm thick, and has no backing material. This is available in either 1 or 5m widths, of which the former is suitable for sand fences. It should be attached to posts spaced at 2m intervals, using three strands of 3.15mm wire threaded through the material and stapled to the stakes. Although black in colour, Enkamat is not too obtrusive as the ‘pockets’ rapidly get filled with sand. As it tends to trap sand within it, this material makes a fairly steep-profiled dune. It is difficult to vandalise.

Wyretex

This is a reinforced fabric of ultra-violet and acid resistant polypropylene and galvanised steel wire, twisted together and then woven. It is manufactured in Scotland, and used for erosion control on banks, as a foundation for roads and tracks and many other uses. Various grades are available, according to the density of the weave. Grade 4 or 5 is suitable for sand fencing. Wyretex is very strong, resists wind and wave action, and is difficult to vandalise. It is a fairly unobtrusive grey colour.

Posts should be spaced 3m apart for mild steel wires, and up to 6m apart for high tensile steel wires. Wyretex is manufactured in 1.5m widths, and is best used to full height on 2.5m posts. Where this height is not required, the bottom 0.5m can be buried in the sand, although this is only serving a useful purpose if undercutting occurs. Thread a top and bottom wire through the fabric, in approximately 300mm-long ‘stitches’. At the posts, fasten the fabric with a vertical batten nailed every 300mm, or alternatively a piece of wire stapled vertically. Do not staple direct through the fabric, or it may tear.

Strawberry netting

Cornwall County Council originally started using this material when they were offered a cheap job lot which had been inadvertently manufactured to the wrong width for strawberry protection. It has proved successful for sand trapping, and is now manufactured in a one metre width, for this purpose. It is a lightweight material, and is not ultra-violet resistant. and thus deteriorates after only a year. However, this has been found sufficient as expertise is gained in positioning of fences, and is a positive advantage as little clearing up is needed of odd lengths or ends which remain exposed. The netting is used double, which makes the fence only slightly cheaper than using Enkamat. An advantage is its pinky-buff colour, which fades to become almost invisible amongst the dunes.

The netting is supported 75mm (3″) from the top and bottom edge by 2.50mm mild steel wires, stapled to 75mm (3″) by 1.1m (43″) posts at 5m (16′) intervals.

The staples are 30 x 2.50mm, galvanised. The netting is attached to the wires with Gerrard (Gordian) ring gun staples every 150mm (6″), and to the posts with a vertical wire stapled to grip the netting against the post. A shallow trench is dug to fit the bottom wire and lower edge of netting, and is backfilled to complete. Formerly, ‘A’ frame strainers were used to support the fence, but these are no longer found necessary, as from better knowledge of fence placement, the fences are quickly buried. Instead, the end posts are held firm by ‘Spanish windlasses’.

Tensar

Netlon Ltd manufacture a range of ‘Tensar’ fencing and windbreak products, and recommend ‘Shelter Shading’ for sand fencing. This is made of high density polyethylene, 1.5mm thick, and with 42% porosity. It is available in 10 x lm and 30 x 1m lengths, and should be supported on 100mm diameter posts at 3m intervals, attached by battens nailed to the posts. The material can be tensioned using Monkey strainers, attached to a 50mm batten or steel pin threaded through the mesh. Do not over-tension. Lengths are joined by overlapping the ends and threading a batten through the two thicknesses. ‘Tensar’ is satisfactory if it remains taut, but if it slackens as sand gathers against it, the weight can cause failure of the fence. Extreme conditions of sunlight and wind at the coast may mean a life of only one year before it deteriorates. Being black, the material is rather obtrusive.

Paraweb

Paraweb is made of terylene filaments, encased in black polyethylene, and is claimed to be durable in extreme conditions of sun and wind for over 15 years. The material is made of 50mm wide horizontal webs, joined with vertical webs, to give 46% porosity. Suitable widths for sand fencing are 1m and 1.4m, supplied in 30m lengths. Like Tensar, it is effective while it remains taut, but can fail from the weight of sand accumulation or undermining by wave action, leaving a tangled mess which is an eyesore and a nuisance to clear up. Both Tensar and Paraweb have the advantage that no wires are necessary, thus lessening the non-degradable content of the fence.

Paraweb can be tensioned with Monkey strainers, and should be attached to posts with battens or special staples available from the manufacturers. The webbing should not be punctured by staples or nails, unless finishing off loose ends not under tension.

Synthetic materials: suppliers

Enkamat
MMG Erosion Control Systems,
Waterloo House, Kings Lynn,
Norfolk PE30 1PA
Tel 0553 774423

Wyretex
Malcolm, Ogilvie and Co Ltd,
Constable Works, Dundee DD3 6NL
Tel 0382 22974

Strawberry Netting
Mr. M Cain, Manor Cottage,
Dark Lane, Chew Magna, Avon.

Tensar
Netlon Ltd,
Kelly Street, Blackburn BB2 4PJ
Tel 0254 62431

Paraweb ICI Linear Composites Ltd,
Hookstone Road, Harrogate, N. Yorkshire
HG2 8QN
Tel 0423 68021