Cable Railing - Design Guidance

All railing installations must comply with applicable standards related to post height and cable spacing. When determining the height of railing posts, individuals should factor in the handrail, type of location, as well as local, city, and/or international building codes (4) . For example, most state residential codes require railings to be 36” (minimum). California (7) is an exception to this standard, which requires railings in the state to be at least 42” (for all residential railing installations). This 42” railing height requirement is also applicable to commercial building codes. The height of posts is measured from the floor to the top of the railing system. 

Cable construction is the combination and arrangement of wires in a wire rope or cable. Numerous wire rope constructions exist, each with unique properties and end-uses. 1x19 strand cable has the smoothest construction while being strong with low flex and stretch properties. These specifications (8) make it the ideal solution for railing applications.

Table of Contents

Overview

Cable railings are versatile, durable assemblies that can be installed in a wide range of indoor and outdoor sites. With this in mind, individuals must consider structural requirements, materials, location of the project, compliance with building codes and more, to ensure a smooth installation. Understanding such elements during (or before) the planning stages of the project may help you avoid bottlenecks and get the most out of your stainless steel railing.

Note: Customers are encouraged to call their local city for information about their local building codes (4) . City building codes supersede national building codes. Inline Design is providing this information in an advisory capacity only. The company is not liable for any non-compliance with applicable building codes associated with railing installations.

What are the Structural Requirements for a Horizontal Railing System?

The presence of cables is what makes cable guardrail systems unique. In order to sustain the pulling force associated with cables, the posts should be sturdy. Additionally, top rails are frequently exposed to light impacts and pressure from objects or individuals leaning on the structure. To safely accommodate such elements, the International Residential Code (2) requires top rails to be capable of sustaining a concentrated load of 200 lbs. (horizontally or vertically) at any point of the railing component. Local building codes may also call for smaller loads at 20 lbs. per square foot applied to the cable infill.

Inline design Cable Railing Post guidance

Do Post Height Requirements Differ?

All railing installations must comply with applicable standards related to post height and cable spacing. When determining the height of railing posts, individuals should factor in the handrail, type of location, as well as local, city, and/or international building codes (4) . For example, most state residential codes require railings to be 36” (minimum). California (7) is an exception to this standard, which requires railings in the state to be at least 42” (for all residential railing installations). This 42” railing height requirement is also applicable to commercial building codes. The height of posts is measured from the floor to the top of the railing system. 

inline design top mount cable railing post height inline design cable railing fascia post height

Why is Post Spacing Important?

Spacing between posts should be kept consistent (when possible) along the railing assembly to assist in the aesthetics. Building code (3) requires that the spacing of posts not exceed an amount that could increase cable deflection, and placing a post around every 4 feet assists to reduce cable deflection. While keeping your cable from sagging it supports your handrail keeping it compliant with defection requirements while maintaining its strength time. To meet the requirements for 36” or 42" posts, a 4-foot spacing (center to center) is what is recommended.

What are the Cable Spacing Requirements?

Guidelines for spacing between cable components are straightforward and simple. According to the International Code Council (4) , openings between cables should not exceed 4”. A 4” sphere should not be able to pass through the openings. To accommodate such standards, railing projects may incorporate less than 3 ½” of spacing between cables taking into account the cable deflection related to post spacing. This configuration assists with the 4” sphere requirement.

inline design 4  inline design ball rule for stairs with cable railing

What makes up Horizontal Cable Count?

Bringing both post height and cable spacing guidelines (4) together with the mounting surface, a railing system with 36” posts utilizes approximately 10 cable horizontal runs. Cable Railing assemblies with 42” posts use roughly 12 cable horizontal runs. This applies for both cable sizes of 1/8" and 5/32".

Cable spacing for cable railing

What is the importance of Cable Construction?

Cable construction is the combination and arrangement of wires in a wire rope or cable. Numerous wire rope constructions exist, each with unique properties and end-uses. 1x19 strand cable has the smoothest construction while being strong with low flex and stretch properties. These specifications (8) make it the ideal solution for railing applications.

cable railing 1x19 cable construction

Are There Different Types of Top Rails?

The top rail completes the load frame required for your cable railing project. Stainless steel is highly recommended for the top rails. The metal is resistant to corrosion, moisture, debris, and light impacts. Marine-grade stainless steel is applicable to railings installed in rugged locations, such as outdoor beachfront properties, docks, outdoor decks, rooftops, etc. Furthermore, stainless steel top rails are suitable for indoor spaces, including commercial sites, offices, and public buildings.

Some project requirements may call for wooden top rails. To ensure long-term structural integrity, individuals should consider mounting a steel bar under the wood top rail for additional support. This can help keep the wood component functional and intact, especially when serving as safety barriers along with decks, stairs, and ramps.

How Big do I Drill Holes for Cable Railing?

Intermediate posts need to be drilled in order to get the cable through. In order to avoid excessive cable deflection, holes should be drilled about 5/64" (or 2mm) bigger than the diameter of the used cable.

How Long can you run Cable Railing?

The cable run can go up to 30 feet on straight runs with 1/8" diameter of 1 x 19 Type 316 Stainless Steel Construction Cable. A cable run consists of a cable tensioner, cable terminal, and a wire. The rule of thumb is that on corners cable runs end.

Are Cable Railings Safe?

Cable railings are structurally safe and meet building code when properly installed. Cable railing structure relies on the tightness of the cable infills. End posts and corner posts need to be strong enough to support the pulling force of the cables. Any opening shall not exceed 4". Though cable deflects therefore opening between cables should be less than 3 ½" depending on the spacing between cable posts.

How do you Tension a Cable Railing?

Each cable run is made from one tensioner, one terminal, and a cable. Apply a tension meter tool on the cable then twist the tensioner hardware enough to have your desired reading on the tension meter. Repeat this process on the remaining cable runs in order to have equal tension on all the cables.

Why are Knowing Your Project Requirements Important?

For large or complex projects, the installed system often includes handrails as one of many assemblies that must be installed in the area. To prevent bottlenecks, it is recommended to double-check field measurements, dimensions, and finalized shop drawings. This crucial step can prevent delays and miscalculations during fabrication. If it is not possible to make field measurements, individuals may obtain guaranteed dimensions from their contractors.

Where field measurements cannot be made without delaying the railing fabrication and delivery, obtain guaranteed dimensions in writing by the Contractor and proceed with fabrication of products to not delay fabrication, delivery, and installation. Coordinate fabrication and delivery schedule of handrails with construction progress and sequence to avoid delay of railing installation.

References

Want to learn more about our railing products? Inline Design offers a variety of solutions. Check out these articles:

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