A stock-proof fence that can withstand New Zealand’s harsh conditions is essential!
It is important to choose quality materials suited to the conditions and maintain a high standard of workmanship when constructing a fence.
The most common mistake in fence construction is erecting the wrong fence for its purpose. Ground contour and the type of stock the fence is designed to manage must be taken into account. The most common types of non electric fences fall into three categories:
Multi wire, multi batten. Often referred to as Conventional fences and sometimes post and wire fences. (Sometimes these fences have some wires electrified)
Post and wire – no battens. Often just called Post and wire fences. (Sometimes these fences have some wires electrified)
Netting Often called Fabricated Netting fences
Naturally these are the common fence designs. Fencers often change these designs to suit their needs. Just because they have been changed doesn’t make them any less effective if they are done well and suit the situation.
Wear Fencing have the team, experience, plant and equipment to get the job done. Contact us here for a quotation.
Industry supplier Wiremark have developed the following fencing guide to help get the job done.
Before you begin fence construction, ensure you have what you need. The following is a broad guide:
gates (if required)
gudgeons (if required)
gate catch (if required)
The exact quantity of materials required is difficult to determine as this will vary from fence to fence. For example, a boundary fence may require more wires to accommodate a greater range of stock applications.
We use high quality materials designed to withstand New Zealand’s diverse conditions.
Uniformity–all posts should be similar in shape and size.
Treatment–posts should be ground treated to meet the manufacturers’ specifications.
Strength–Check that posts are free of knots, and check their density to ensure that they are durable.
Labelling–check the labelling to ensure that the wire has an adequate protective coating as this will determine the life span of the wire.
Ductility–the wire should be easy to handle and shouldn’t tangle.
Suitability–check the gauge and tensile strength of the wire to ensure that you have the right wire for the type/purpose of the fence being constructed. Eg. 4mm heavy galvanised wire is suitable for equine fencing.
Zinc-aluminium wires are designed for use in corrosive areas, such as coastal or sulphuric regions, or when fertilisers are used. Zinc-aluminum wires are coated with 5% aluminium and 95% zinc. The small aluminium addition enhances the performance of the coating, making it more resilient to corrosion.
Zinc-aluminium wire will last up to four times longer than heavily galvanised wire when used in the same conditions.
The process of fence construction
There are many methods of fence construction. We’ve called on the experience of some of New Zealand’s leading fencing contractors for tips on efficient and correct fence construction.
Before you begin your fence construction, walk the entire length of the fence noting any directional changes and the contour of the ground.
Fence construction begins with the installation of the end strainer assemblies and any angle posts. These should be installed so that they are firmly lodged in the ground.
Once the end strainer assemblies and angle posts have been correctly positioned, a guide wire should be run out and temporarily tensioned so that it is straight from point to point throughout its entire length. This will provide an accurate guide for the fence to follow. Two wires can be used to ensure that posts are positioned vertically and in line. If one wire is positioned forward slightly, it will mean that the post won’t be straight. So long as a gap of about 5mm is left between the guide wires and the posts, every post should be straight along the entire fence line.
Mark the ground beside the guide wire where the line posts are to be installed. To ensure that the fence stays parallel to the ground, identify any changes in ground contour and alter post spacings accordingly.
The distance between line posts varies depending on these ground contours, but normal line post spacing is between 4 to 5 metres for a boundary fence.
Post installation begins with the main rise posts (highest points of the fence line) and the main dip posts (lowest points of the fence line). Once these have been installed and the guide wire(s) attached to them, it then allows the fencer to install the other line posts correctly.
The chosen wire spacings, or gauges, are then marked onto all posts. The remaining line wires are run out and attached to the main rise and dip posts. These should be the only posts that have all the line wires attached before tensioning.
Once all line wires are correctly tensioned and tied off, the remaining posts can be stapled, starting with any intermediate rise and dip posts.
Begin battening now if required. Battens must be set at an equal distance between posts; normal spacing is between 0.5m to 1 .5m.
Strainer posts mark the end/beginning of the fence and are considered the most important posts in the fence line. They carry the strain of the fence and support any gates if necessary.
In parts of New Zealand, where soil conditions are wet, a horizontal end assembly is sometimes preferred to a diagonal stay.
Before the hole for the strainer is prepared, attention must be given to the surrounding ground contour, as this will determine the strainer position.
Strainers should be good quality and as straight as possible. As a general rule of thumb, the strainer length should be double the fence height. Strainers that are 2 00mm SED (small end diameter) by 2 .4m long would suit most fences.
Strainers on flat ground should stand vertical and on sloping ground 90º to the contour of the land. Angle and line posts should be placed in the same manner, so they bisect the angle of the wires perfectly and ensure the spacing of the wires remains consistent.
During construction, it is best to lay the strainer back slightly against the strain; this will allow for forward movement after tensioning.
When the hole is prepared, check for correct depth –it should be approximately half of the strainer length. Once the post has been dropped in, check for correct height and ensure it is standing against the stay side of the hole.
Footing the strainer
Strainer posts need to be firmly footed in the ground to ensure that they don’t lift or rotate.
Foot size can vary depending on the type of ground. Usually the softer the ground, the bigger the foot. In firm ground two foots 380mm long x 1 00mm wide should be sufficient. Wire used for footing should be 4mm heavily galvanised steel or 3.15mm stainless steel wire.
Two foots should be placed on either side of the strainer at the bottom of the hole. A block of timber should then be laid across the back of both foots, as this will add extra strength and prevent upwards movement.
Construction of the foot
The foot consists of a piece of ground treated timber with a 4.00mm or 3.15mm heavily galvanised stainless steel wire stapled in the middle, on the underside of the foot.
The wire should be at right angles to the foot and well stapled.
Bend the wire around the foot and neatly wrap the short end around the long wire using a pair of pliers. The tails should be left long to avoid unravelling.
Straighten the long wire by running it through your hands, counter to the natural coil/curve of the wire, while you stand on the foot.
Installing the foot and ramming
Place one foot beside the strainer so that it finishes flat against the bottom of the hole. Follow with the second foot on the other side.
Check that the foot wires spiral half a turn around the strainer in the direction of anticipated movement, as this will avoid rotating and lifting –ie. if the line wires of the fence leave the right side of the strainer, the left foot wire should be fixed on the right side of the strainer.
Staple any wires clear off the ground to avoid corrosion.
Place a block of timber across the top of both foots at the back of the strainer. This will tension the foot wires, increasing holding power and preventing backward movement.
Using one staple, staple the foot wires to the post approximately 150-200mm above the ground to ensure that the staples don’t come into contact with the soil. The staple should be 45º across the wire and driven in firmly so that the wire has to be drawn through it under tension.
Check the foot to ensure that it is securely in place.
With the foot in place, ramming can now begin. Use four separate fillings as it is important that the soil around the foot is well compacted. While ramming, constantly check that the strainer is in the desired position (flat against the front of the hole).
When ramming is complete, the desired wire gauge can be marked on the strainer. This should be done on both sides and will help ensure accurate and neat positioning of wires when tying off.
The Stay The stay is used to support the strainer against the strain of the line wires. The more wires, the more tension the stay must support. A suitable length stay that is free of knots and of good diameter should be used. A stay that is 2400mm by 12 5 SED is recommended.
Trimming of the stay Care should be taken not to over trim the stay, as this gives less bearing area where contact is made.
A round stay should be trimmed to square at the end and taper out to nothing by about 2 50 to 300 millimetres. The exact length of trim is not too important.
Once the stay has been trimmed, cut the bevel on the end. The bevel is a small angled face above the bearing surface of the stay, which acts as a support. The angle this is cut at will depend on the ground contour between the strainer and the stay block. The object is to get the stay and mortice to fit flush. This can be achieved by setting the stay against the strainer where its final position will be and then lifting the stay above this position by the approximate distance in which the block end of the stay will be buried in the ground.
A parallel line should then be scribed into the stay using a flat rule/level to ensure that it is accurate.
Position of the stay
Opinions vary as to how high or low the stay should be on the strainers, but half way between the ground and top is suitable in most cases. A high stay will increase tension on the footing and low stay will put too much pressure on the stay block. The exact position is determined by the wire gauge and the size of the wires in use. The stay must not be in the way when tying the wires.
Once the height has been determined, rest the trimmed stay at this height and check to see if it is in line with where the wires will run. Do this by either sighting the already straightened, or tensioned guide wires, or by standing behind the strainer and sighting in the direction of the intended fence line. Careful sighting and lining of the stay is very important and if done incorrectly, may cause the mortice to be off centre, resulting in the twisting of the strainer.
The stay should be scribed to mark where the mortice needs to be chiselled out. This should be neatly done across and down each side, right against the stay, but about 6mm to 1 0mm underneath. This gap will be filled when the stay is put into the ground and is essential in preventing the splitting of the stay. Chisel out the mortice to about 2 0mm deep. Try the stay for fit and then realign as before. With the stay now fitted and in its correct line position, the stay block can be fitted.
Fitting of the stay block
The stay block provides the stay with extra support by giving it a greater bearing surface where it comes into contact with the ground.
Failure of the stay block means strainer movement, wire tension loss and a non stock-proof fence. Choosing a suitable stay block will depend on the soil type –the softer the ground, the bigger the stay block will need to be.
Where the subsoil is firm, a 900mm by 2 00mm bearing surface is required. In soft ground, the length of the stay block should be increased.
With the stay in its exact position the stay block trench can be marked out. This will be positioned horizontally in the ground. The stay should hit the stay block at mid point to ensure the bearing is in the middle of the stay block and the stay doesn’t twist once it comes under pressure.
Dig out the length of the block, and as deep as is necessary for it to be in stable ground. eg. subsoil.
Place the block in the trench and thump it several times along its length, as this will ensure it is well embedded and won’t move during the final fitting.
Dig a sloping scarf to let the stay meet the block.
Insert the stay in the mortice and lower it onto the block. It should fit about half way across the block diameter.
Raise it slightly and insert a spade in between the block face and the end of the stay. Use your foot to apply some weight to the stay and thump it down to halfway on the block using a rammer.
Remove the spade and centre the stay on the block face and in perfect line with the fence wires.
Cover in the block and turf it down neatly.
Angle posts are substantially-sized posts that define changes in the direction of the fence.
Angles of up to 45º can be sustained by a 21 00mm post, however angles of 45º-90º are under a considerably higher amount of strain, so a more substantial 2 400mm angle post should be used.
The installation of angle posts (angles) is similar to strainers. Contour, shape and footing remain the same, except that the foot wires are not spiralled but stapled directly above the foot.
It is recommended that the stay should be a little lower than half the height of the post as this deters stock, especially sheep, from rubbing under the stay and causing erosion.
The stay should bisect the angle created by the fence wires. This is important as it ensures that the weight and tension of the fence is balanced equally.
Rise and dip posts
Rise and dip posts define the high and low points in a fence line. Used only when needed, these posts hold the fence in line and counteract the upwards or downwards pull of the wires.
Rise posts should be set 2 5mm higher and dip posts should be placed 2 5mm lower to maintain bottom wire height. This will ensure ground clearance if the rise post should sink, or the dip posts should lift.
As dip posts are under a considerable amount of tension, they need to be firmly footed into the ground.
One of the more popular and frequently used methods of footing for dip posts is the swinging foot.
Installing the swinging foot
With your post in the hole and correctly positioned, ram around the bottom of the post to ensure that your rammer fits.
Bend the foot wire flat along the heel of the foot, so that it is parallel to the foot.
Place the foot alongside the post pointing downward and to the bottom front corner of the hole.
Tap the end to drive the point forward and under the front face of the hole. When the wire is about 2 5mm from the face of the hole, ram the foot neatly flat. At this stage, the heel should be 75mm off the bottom of the hole. This is important as it ensures the bottom of the post is well heeled and won’t shift position when the foot is installed.
With one staple, staple the wire to the post above the ground. The staple should be 45º across the wire and driven in firmly so that the wire has to be drawn through under tension.
Now, finish the ramming of the foot flat to the bottom of the hole which will result in the tightening of the foot wire.
Fill the hole one quarter with earth and ram well.
Now staple off in an approved manner (outlined on page 1 0)
Ram the earth again as the stapling may have caused the post to loosen a little.
Check for contour, lean, and continue by ramming the remaining earth.
Line posts (also known as intermediate posts), support the wires on the fence and run between any rise and dip posts. They are ordinary-sized posts strategically spaced to give the fence ground clearance.
Regardless of whether round, half round, or 1/4 round posts, the technique for posting generally remains the same. Good compaction is highly important. The setting of posts depends on the contour of the land; the more undulating the contour the greater the number of posts.
In very hilly country, blading of the proposed line could be a financial advantage as fewer posts would be required.
As posts can vary in length, it is most important to check every post for height before starting to ram the earth around it.
Any post which has an upward lift, should be considered for footing. Posts should be faced neatly to the wire with their straightest portion. Some round posts have cracks, or splits and these should be avoided as a face side.
Avoid any sharp bends in the foot wires at stapled points, as this weakens the wire and it can break under tension.
Wiremark-endorsed wire is performance tested for strength and ductility. Using inferior wire products can lead to inconsistencies and handling issues which, in the long run, can lengthen the time taken to erect a fence and is invariably more costly.
Begin wiring at the highest strainer on a hilly contour, as it is easier to drag the wire downhill.
Ensure that you select the correct end of the coil and put it uppermost on the wire dispenser. Remember that the coil must always be dispensed anticlockwise. Dispense in a smooth motion, as any sudden starts and stops can cause the wire dispenser to overrun and drop outside the dispenser’s guide arms.
Run out one wire after another and either tie off, or push the ends in the ground when the fence end is reached, to stop it from recoiling.
Where two wires join together, a strong and durable knot is needed to ensure that they don’t come apart.
There are a variety of knots which can be tied to join a wire. Under laboratory tests, carried out at Pacific Wire, on Wiremark wire, the following results came to light.
Average breaking strain
Reef Knot 440kgf*
Figure 8 Knot 470kgf
Crimp Sleeve 620kgf
Double Loop 290kgf
(Double Loop should not be used). *Kgf refers to kilograms of force.
From these results it’s clear that the easy-to-tie figure 8 is one of the better knots. After the wires are strained to the correct tension, the surplus wire ends of the knot are wrapped closely along the line wire and broken off close to it. This gives a smooth finish and when done correctly you should be able to run your hand either way along the line wire.
Rise and dip posts should be stapled first and the remaining stapled off after tensioning.
Staple at 45˚ to the line of the wire leaving space so you can’t quite fit a second wire through. This will allow the wire to feed through the staples when tensioning and prevent wind chatter.
On an angle post, a second staple should be put behind the wire so that the wire slides easily.
On long strains, especially if two or three angles are included, be sure to leave one or two-footed posts unstapled at the farthest end from where you wish to strain. This will ensure an even tension along the entire line.
Once all wires are tied off, stapling of the remaining posts can begin. Start this by walking the entire length of the fence and stapling only secondary foots and rises, as this will even the wire tension.
In sharp dips and rises, two staples are recommended for better holding (as shown in the diagram).
Straining up & wire tensions
When all the posts along the fence line are in place, and any rise and dip posts have been stapled, tensioning or straining up of the line wires can begin.
Before beginning any straining, the breaking strain of the wire should be noted. These can be found by reading the wire specifications (see back cover). As a general rule, wires should be strained to a quarter of the breaking strain of the wire.
In the example of 2 .5mm high tensile wire, the breaking strain is 620kgf*, giving a recommended tension of 1 50kgf.
Straining from top to bottom is recommended as you will get less sideways movement of posts. Angle posts, stays and stay blocks will also settle quicker, as the leverage at the top of the end strainers and angles is immediate.
Apply the chain wire strainers to the top two wires and draw them to a tension of 340kgf using a wire tension indicator. This is pre-stressing tension only, and will draw the fence wire to the furthermost end, bedding/locking it in on the strainer.
Pull it through any staples, which may have been incorrectly driven, or skewed and close up any reef or figure 8 knots which may have been tied.
Now slacken off the top wire until the chain wire strainers are sagging. Then re-tension so that the finished tied off wire is 1 50kgf, the recommended tension to tie a fence off at.
Remove the chain strainers and pre-stress the No. 3 wire with them.
Slacken No. 2 and re-tension etc. and work down the strainer post from top to bottom.
Staple off the rest of the wires.
Note: Do not have more than two wires at 340kgf at once, as this could be damaging to dip, angle and strainer posts.
*kgf refers to kilograms of force
To ensure that wire spacing remains consistent, and to improve stock retention, wooden battens should be stapled to the fence between any line posts.
The purpose of battens is to maintain wire spacing so that cattle can’t push their heads through the fence. Even if posts are three metres apart, at least one batten is desirable.
To ensure even batten spacing between posts, use a length of elastic with the number of battens being used marked upon it. When stretched between posts this will ensure even batten spacing. Place the batten against the wires with about 50mm above the top wire and hold it with some pressure applied with your knee.
Staple the five top wires while holding it in this manner. Check that the batten is at an exact right angle to the wire.
Hang all battens in this method and staple the remaining wires from the opposite side. Staples must be skewed and staggered alternatively. Also they must be driven firmly in, actually causing an impression by the wire in the timber. At no stage should daylight be seen between staple and wire.
Check that all battens are uniform in height above the top wire, but not higher than the posts. Square off battens prior to stapling. If you straighten the batten after stapling, you may need to re-hammer the staples as they may have loosened.
Every effort should be made to have gate tops and strainers level at all times. Correct positioning of strainers in relation to contour is important for successful gate hanging.
The strainer on which the gate is hung must be at right angles to the ground in the gateway. It is possible to hang a gate on sloping ground by observing this rule.
Clamps on steel gates must be as far apart as possible, that is, just below the bend at the top and between the second-to-bottom and the bottom bars.
After these adjustments have been made, stand the gate in the gateway level with the top of the strainer. Check to see the gate is plumb, and then mark just under the eyes of the hinges. If the gate is not plumb, it will either rise or fall as it opens. Where possible, gates should be able to open back against the fence.
On wooden gates top strap down on top bar. Bottom strap up on bottom bar. Straps MUST be equal distance from upright to hinge eye.
Be careful to position gate so gudgeon is in a position to clear gate on opening and will not become hinge bound.
Livestock, weather and human interference can all cause damage to a fence. Repairs to fences are a relatively simple procedure, as quite often only the wires will need to be replaced. How to repair a broken or damaged fenceFirst of all assess the damage to the fence and establish at what point the strength of the fence line has been compromised.
Pare back the fence to an appropriate distance from either side of the damaged area.
Replace any damaged posts. Be sure to check the end strainer posts and stays to ensure that their strength hasn’t been compromised.
Run out new wires, connecting the new wires with the old wires. This can be done by using a strong knot such as a figure 8.
Strain up each of the new wires, starting from top to bottom.
Re-strain each wire to the correct wire tension. Note: Wires will need to be re-strained together, or at the same time using separate tensioners.
Tie off the wires and replace any battens as required.
The fundamental difference between a traditional fence and an electric fence is the nature of its stock retention. An electric fence relies on a pulse of electricity to retain stock, whereas a traditional fence relies solely on its structure.
Electric fences are generally used on cattle and livestock farms for greater grazing flexibility.
As electric fence construction is relatively similar to normal fence construction, the following is a list of extra components that are needed:
Energiser–The power supply for an energiser can be mains, solar, or battery powered.
Insulators–End and post insulators are required to contain electricity and stop earthing.
Underground cables–Used for gateways to carry on the electricity flow.
Line taps–Connect the wires carrying power through the fence.
On/off switches–Used to isolate sections of the fence. Earth rod–Used to complete the circuit and should be made of galvanised steel.
For an electric fence to be effective, all wires must be completely insulated and away from the ground.
Wire should be insulated from the strainer with an end insulator. As the strain of the wire is not crucial to stock retention, it should be tensioned at approximately half the normal tension force (80kgf* for 2 .5mm high tensile). The connector wire between the energiser and the fence should be made of zinc-coated wire wrapped in a high density plastic, or polycoated jacket. It should be connected to the positive side of the electric fence unit and should be placed underground to protect it from cattle damage.
If the energiser is powered by a mains system, this should be set up in an undercover area.
If using a battery powered, or solar powered energiser, ensure that it is placed close to the fence line on the opposite side of where livestock is grazing. Both should be installed so that they don’t come into contact with the ground, as moisture can cause damage.
Earth rods ensure that the electric circuit is complete.
Ideally they would be placed at regular three metre intervals along the fence line.
Where live wires need to be connected to each other, line clamps should be placed across the wire to create a bridge for the electricity to travel over.
Test the current/power of the fence to ensure that you meet the manufacturer’s specifications. This can be done using electric fence testers.
Ensure that the on/off switch for the energiser is located somewhere where it can easily be accessed, should the power to the fence need to be cut.
*kgf refers to kilograms of force
Horizontal end assembly
Where the soil type is unable to adequately support a stay and stay block a horizontal end assembly can be used.
The main strainer is mechanically driven into the ground. It should be a substantial post, 2 400mm in length with an SED of 2 00mm.
Determine the position of the No. 2 post, which is 21 00mm by 1 50mm SED. This is done by laying the stay, which is 2 400mm by 12 5mm SED, on the ground and allowing for it to overlap both posts by 30–40mm.
Drive the No.2 post into the fence line.
Place the stay across the strainer and No.2 post so that it sits centre on both and 30–40mm from the edge.
Mortice the stay into both posts to give it maximum bearing surface. It should be positioned with a flush fit, as this will ensure that the stay does not penetrate the posts. The stay should sit 75mm from the top of the strainer and No. 2 posts.
NOTE: The point where the stay meets the post are considered to be the compression joint, so it is very important to ensure that it is morticed correctly.
The Brace Wire
Before bracing, check that all posts are positioned correctly and at the right depth.
Choosing the right wire and correct installation is crucial. Wiremark zinc aluminium 2 .5mm HT wire is ideal, as its strength and ductility suits the application.
To apply the brace wire you will need three continuous loops of wire. These should be placed in line and over the top of each other starting from the bottom back of the strainer and going to the top back of the No. 2 post.
First, half-drive one staple horizontally at the back of the strainer and approximately 1 00mm from the ground. Then half-drive another staple 75mm down from the top back of the No. 2 post to support the wires.
Place wire strainers on either end of the wire that makes up the three continuous loops, and tighten. Use your hand to occasionally work the wire out evenly.
During tensioning, lay the strainer back enough to allow for loading/tension on the line wires. This will happen as the brace wire is tightened.
To tie off the brace wires, use a non-slip wire joint or a crimp sleeve, as this will maintain the full strength of the brace and ensure that no tension is lost. Before tying, the strainer should be laid back approximately 2 5mm to allow for movement.
Finally, adjust any staples, ensuring that the wire can still move freely through them and support the loop wires in their intended position.
View this great resource from Wiremark online here