Fence Construction
A woven wire fence is made of a number of horizontal wires (line wires) and vertical wires (stay wires) secured by a knot to form a grid pattern. The spacing of the line wires and stay wires, along with the overall height of the fence is one of the important factors in selecting the correct fence for your application, but equally important are the grade of steel wire used, the knot formation, the coating and the overall construction of the fence. Here we examine the choices:
Line Wire
Low Carbon vs High Tensile. Both of these types of steel wire are used in fence construction. There are two properties of the wire that make these options noticeably different. Firstly breaking strength. Typically a 12.5 gauge carbon steel wire will have a breaking strength in the region of 600lbs, compared to 1400lbs for a high tensile wire of the same gauge. Secondly the elongation rate is very different in low carbon steel versus high tensile. A low carbon wire will have an elongation at break of around 14% compared to about 3% for high tensile. In practice an exaggerated comparison would be low carbon is a piece of chewing gum and high tensile a length of elastic. What this means is that a fence constructed from low carbon line wires will stretch more bot on installation and throughout the seasons. This is why heavier top and bottom line wires are needed to stop the fence being overstretched on installation. High tensile needs significantly less ongoing maintenance as its elasticity allows it to better cope with the installation process and the expansion and contraction through temperature change
DEEP LINE WIRE CRIMPS OR TENSION CURVES Fixed Knot and square knot fencing have a deeper crimp on the line wires than conventional fencing. This helps to increase the flexibility of the fence both with temperature changes and after impact, allowing the fence to regain it’s original structure. The deeper crimp also means that the fencing will adjust more easily to uneven terrain.
Knot Types
FIXED KNOT fence uses a third wire that is twisted under pressure around both the vertical and horizontal wires forming the knot and locking the joint tight. This knot provides far greater vertical and horizontal holding strength. Even under heavy pressure, the fence cannot be torn apart unless the pressure is sufficient to cause the wire itself to fail, an extremely unlikely event.
SQUARE KNOT fence employs a continuous stay but has a much smaller compact knot than the fixed knot fence. This is especially useful in the construction of horse fence as their are no sharp edges to the knot as can be the case with the other two knot formations. Whilst not as strong as the fixed knot, the square knot allows for a continuous stay that makes for easier fence installation and it has application in livestock fencing where the pressure on the fence line is not high, such as sheep and goats.
HINGED JOINT fence uses individual pieces of wire between the horizontal line wires, wrapping around to secure them. The fence is a rapid one to manufacture and is commonly made from lower cost low carbon steel, meaning it has become as favourite of the DIY or landowner fence installer.
Stay Wires
SOLID VERTICAL STAYS VS INDIVIDUAL WRAPPED STAYS. The solid vertical stay in fixed-knot and square knot fence gives the fence vertical strength. The fence actually stands unsupported, even before tightening. Continuous stay fencing needs fewer posts giving a significant saving on overall costs. Traditional hinge-joint farm fence has a natural tendency to fold at each knot, causing the fence to sag during installation; a trait not conducive to installing long runs of fence.
Coating
All our fencing wire is produced with Class 3 coating, which is almost triple the zinc rust protection on most conventional commercially galvanized (Class 1) farm fencing.