Commonly Perceived Challenges with Cable Railing Installations – and How to Overcome Them
Making cable railing installation more efficient for your business
As the concept of daylighting continues to spread through the design world, the demand for building elements that maximize the impact of natural light has grown as well. When considering a design for a railing that maximizes sightlines, most look to glass railing options as the solution. However, don’t overlook cable railing as a solution when the goal is to create open and clean views as with balcony or deck applications.
While many fabricators have familiarity working with cable railing, even the most experienced professional can benefit from strategies to address common challenges for a more efficient and profitable installation. Here are four commonly perceived challenges that don’t have to slow you down, and things to keep in mind for your next – or first – cable railing installation.
Matching Products with Actual Dimensions: Ensuring optimal measurements for all aspects of railing height and intermediate post distance may seem like a given for any railing installation. But if the dimensions are based on projections and not on actual dimensions, that can result in the need for product reorder, timely adjustments and slow downs on the job. For this reason, dimensions based on the actual field conditions – after the deck is built or the concrete poured – are extremely important prior to ordering your cable and fittings. The bottom line, make sure to base product orders on accurate field dimensions when ordering your product to ensure the product is the right fit.
Balancing Load Requirements and Aesthetics: As with any railing project, load bearing ability of a well-designed cable railing begins with the choice of post design. However, when choosing a post for a cable railing, in addition to meeting the structural load requirements as defined by the building codes, you will also need to choose a post size that can withstand the stresses related to the tensioning of the cables.
Steel or stainless steel pipe; and 4 x 4 wood posts are the most common post elements used in cable railing. However, other designs have been used with success as long as end posts are chosen to withstand the stress of the cable tensioning.
Include load bearing in cable railing post selection and follow the manufacturer’s recommendation as to the cable tensioning sequence. Your supplier will also recommend minimum dimensions for your post. A good supplier can also provide pre-drilled and counterbored posts; and pre-swaged cable assemblies to simplify the installation process.
Confirming Structural Ability: Post size is not enough to confirm the structural ability of your cable railing installation. For example, a two-inch, schedule 80 steel pipe post would certainly have the ability to withstand a structural load. However, if you surface mount that post to a wood deck with a cover flange and some screws, it’s poses potential structural risks and highlights the importance of embedded attachments. The point is cable railing uniquely adds tension that impacts structural ability. To confirm structural ability and prevent any costly-time consuming re-work, take the time to attach or embed the post in a manner that will provide a structurally stable environment for the later introduction of the cables.
Adhering to Proper Tension Schedules: How often have you seen cable railings as you wander about where the cables droop between posts? Unfortunately, it’s not uncommon. Cable and fittings do not all perform equally against various conditions. That’s why understanding and applying the proper schedule for end and intermediate posts as well as top rail.
It’s important to understand the incredible amount of tension that can be generated on with multiple lines (i.e. ten or more). Consider, that often each is often tensioned at 400 lbs. over a height of 36″ to 42″ – which is why recognizing the amount of the tension applied to the posts is critical. Cable that stretches easily under tension, will sag over time resulting in unhappy clients and code inspectors.
If your cable railing is considered to be a guard, you will also need to make sure that no opening is large enough to allow the passage of a four-inch sphere. For horizontal guardrailing in-fill cables not properly tensioned, can fail this 4-inch sphere test – and for the installer that is a liability. Consider spacing your cables at 3 to 3.25 inches on center; tension properly; and include posts or cable supports every 48 inches. Additionally, don’t make assumptions about stainless steel cable. It’s available in different strand diameters and configurations – many of which allow for too much stretch.
Not only is it a liability, but the tensioning process can cause considerable bending as the cables are being tensioned or even when properly tensioned without an acceptable amount of post deflection. The posts to which hardware is mounted must be constructed so that they will not deflect perceptively as the cables are tensioned.
Cable railing hardware choice will depend on your post selection and the amount of field labor you are able to provide. Parts can be provided pre-swaged from the manufacturer or tools may be purchased or rented to permit final assembly at the job site. Swageless fittings are now readily available to further simplify the installation of cable railings.
Don’t let challenges get in the way of opportunity
While your particular application is unique to you, it’s likely that your supplier has the experience and knowledge to provide you with the best solution. Your supplier as a resource can guide in selecting and working with the right material, and serve as a resource for questions to match each job for a given installation. As the design world continues leverage cable railing for open and clean view, you don’t have to let the challenges stop you from getting the most out of cable railing systems.