Wire rope balustrades are quite common nowadays especially if a modern and sophisticated look is required.
There are two types of wire rope balustrades available. The first is a 5mm stainless steel cable or rope attached to the uprights of the balustrade which should be balau of about 60mm x 60mm. This is attached using a turnbuckle as depicted in the image and can be tightened as time goes by and the wire rope stretches slightly. The tension of this rope should be taught but not too tight. This 5mm cable or rope can normally turn corners and hence less turnbuckles are required per length of wire rope.
The second method, and my preferred one, is a 4mm marine grade stainless steel wire rope with button heads on either end. The 4mm wire rope is normally of a higher grade than the 5mm rope and tends to tarnish less over time. I have found the 5mm rope to often contain one rogue strand which will tarnish and spoil the look of your balustrade. This method requires button heads on either end but the 4mm rope normally cannot turn corners and more button heads are therefore required. Each length of rope should run in one continuous straight run and a new length started once a corner is encountered. A hole is simply drilled into the balau uprights, the button head inserted and the wire rope threaded through and crimped. It too can then be tightened and again it should be taught rather than too tight.
Care should be taken to drill level holes that are equidistant as the slightest difference will be noticeable. Particular care should also be taken when drilling holes on uprights that are on diagonal stairs. A trick is to snap a chalk line the total length of the required wire rope and then drill the balau upright from both ends with the holes meeting in the middle. One cannot see any kink in the wire rope inside the timber but it is more noticeable where it enters and exits the balau upright.
It is normally better to install the wire rope balustrade after the balau has been sealed or coated as this will eliminate the chance of accidentally coating or sealing the button heads or turnbuckles.
Both methods require a crimping tool to crimp the button heads or turnbuckles on either end. This can be purchased often at a considerable price or one can be made using a large bolt cutter and adapting the head. However, only attempt making one yourself if you have the skills and the correct tools, as the correct crimping is vital to ensure that the wire rope does not pull out of the button head or turnbuckle, resulting in a fresh length of wire rope having to be used.
The capping on top depends on choice but I have mostly used a 30 x 102 balau capping which is fastened using kalgard screws to the top of the uprights. Again use as long a length as possible in any one straight run and if a join is necessary ensure that a 45° angle is cut to reduce lifting on the join.
- Timber or Wooden Balustrades (thewoodjoint.co.za)