Cable Railing Design Considerations
Railing cables are an elegant way define a space. Whether the job spans hundreds of feet or just a few, there are some key considerations for a successful application. Here are some considerations to consider for the design of cable railing. To start, always consult with your local zoning and regulation official to ensure you are designing to the proper local code.
For simplicity sake, in this post, balustrade is defined as railing; the two terms are practically interchangeable. A balustrade is a row of posts, topped by a rail, and a railing is a rail supported by posts.
There are plenty of options for balustrade design but our main focus is on cable fill. Cables give balustrades and railings a sense of space and style. With careful planning and design, they have the ability to totally transform the look of the space. The simple and clean lines create a sleek and modern aesthetic, while offering uninterrupted views. Some benefits of choosing a cable infill include the ease of installation and low maintenance factor after install. However whether you are a professional installer or a DIY kind of person, there are key design steps which must be followed for successful application of railing cable, to ensure the cables provide the essential barrier to prevent falls.
1. Decide on Vertical or Horizontal Cable Applications
This primary consideration is driven by a combination of aesthetics and building regulations. Some codes prohibit the application of horizontal cables where a finished floor height is a specific distance above ground. We recommend reviewing the regulations local to your area before selecting.
2. Post Design
Aesthetics are structural integrity are important design considerations when selecting posts. End posts must be adequately designed to cope with the loads necessary to resist cable deflection when forces are applied.
3. Post spacings, Span and Cable Tension
The span or distance between posts on a railing has a direct relationship to deflection. With increased spacings higher tensions need to be applied to resist deflection. Depending on which Ronstan balustrade cable system you pick, there is a maximum span listed.
4. Cable Diameter, Construction and Grade
Cable stretch is a consideration when selecting a diameter; larger diameter cables resist elongation better at a given load. 1/8″ (3mm) – 3/16″ (5mm) are common diameters. Check your local code.
Will your cable be turning any corners? Although 1 x 19 construction offers the lowest stretch over long distances, 7 x 7 cable is more flexible for multiple changes of direction. Grade 316 is widely considered the default stainless steel grade for balustrade cables as it offers the best corrosion resistance, strength and aesthetic properties.
5. Cable Spacing
Local codes dictate required cable spacing; there is only a minimum amount of deflection allowed. Typically it is 3-4″ but consult with the local code authority when designing. In general, a good practice is to design cable spacings closer than the local code requires.
6. Connections, Fittings and Material
Stainless Steel offers crisp, clean aesthetics, low maintenance, and structural integrity, as long as it is sourced from quality manufacturers. Our cable systems are manufactured to ISO9001-2000 and are load rated and designed specifically for balustrade and railing applications. Our connectors can be used in timber or metal posts. It is up to the designer to figure out how much tensioning you will need in order to decide which system is appropriate for you (i.e do you need tensioning at both ends or just one?). The remaining choices are based on aesthetics and how much room there will be for installation and tensioning. There is a system and a connection component for many designs, so if you have questions, don’t hesitate to contact one of our sales staff today.
All photos provided by Ronstantensilearch.com and of completed Ronstan balustrade projects around the world.