When it comes to railing infill, most people immediately think of vertical pickets, horizontal rails, or
glass panels. However, today's cable railing infill options offer many benefits:
- Very strong
- Extremely durable
- Low maintenance
- Easy to use
- Virtually invisible
Perfect for projects with a view
Advantages of Cable Railing Assemblies
- Cable has strong tensile strength with minimal stretch; excellent for strong, durable infill barriers.
- Wide variety of cable fittings are available to meet virtually any attachment condition and design need.
- Cable assemblies can be installed on wood or metal frames.
- Cables are slender and unobtrusive and will not impair views through the railing.
- Stainless steel ensures durability, low maintenance, and lasting beauty.
Versatility of Cable Railing Assemblies
Cable railing assemblies can be used on wood or metal railings, fences, or trellises in exterior, interior,
residential, or commercial settings. Please note, however, that the cables, fittings, and assemblies discussed in this
presentation should never be used for lifting, hanging, or other high-load conditions; the manufacturer can recommend
other cables and components for these types of critical applications.
Advantages of Prefabricated Cable Railing Assembly Kits
Feeney offers cable assemblies in standardized kits or packages with pre-cut lengths and predetermined end
fittings. The benefits include:
- Save time and money.
- Standardized lengths simplify ordering.
- Excess cable is trimmed in the field so exact railing measurements are not necessary when ordering.
- Special cable fittings make installations quick and easy.
- No special crimp tools are required.
Cable Assembly Care and Maintenance
Cable railing assemblies are typically made from type 316 stainless steel for weather-tough durability and
very low maintenance. The protective chromium oxide on the surface of stainless steel gives it superior corrosion
Properly maintained, stainless steel provides excellent luster, strength, and durability. In most applications, stainless
steel will not rust or stain even after many years of service; however, it is not rust or stain proof. With proper care and
maintenance, as specified by a manufacturer, cable railing assemblies can remain beautiful and functional even when exposed
to harsh marine environments.
CableRail assembly care and maintenance recommendations and practices include:
- Only clean stainless steel with soap and water or a stainless steel cleaner. Never clean with mineral acids or bleaches.
- Always remove stains or rust spots as soon as possible with either soap and water or a stainless steel cleaner.
- Never leave stainless in contact with iron, steel, or other metals. This can cause rust spots or corrosion.
- Never use coarse abrasives like sandpaper or steel wool on stainless. Use synthetic general purpose scouring pads instead.
- Important: Periodically inspect cable assemblies for proper tension and re-tension as necessary.
As mentioned, cables can be used on wood or metal railing frames, but the frames need to be structurally sound.
That is, they need to be designed and built strong enough to not only meet code requirements but also support the tension of
properly installed cables, which could exceed 300 lbs per cable. In addition, frames should be designed to use cable infill
efficiently, thereby saving materials, time, and money.
This section will outline some basic guidelines on how to properly prepare railing frames for cable infill. These guidelines
will apply, whether using 1/8", 3/16", or 1/4" diameter cable assemblies.
End and Corner Posts Requirements
The end and corner posts need to be strong enough to support the full tension of the cables, which could exceed 300 lbs
per cable. Below are recommended minimum sizes for the end and corner posts only. The intermediate posts do not support
any tension load and only need to be sized as necessary to support the cap rails and meet railing frame code
Basic Frame Design Requirements
Spacing From Walls: Set end posts three to four inches away from any wall face to allow access for attaching cable end fittings.
End Posts: Use minimum end post sizes as noted on the previous slide and securely bolt or lag to joists or deck surface.
Intermediate Posts: Sized as required for cap rail support strength or for code.
Double Corner Posts: If possible, use double corner posts to allow the cable to run continuously through the corners without terminating.
This will save money by reducing the overall number of cable assemblies needed.
Post Spacing: Space all posts and vertical spacers a maximum of three feet apart to minimize any deflection
that may occur if the cables are ever forced apart.
Cap Rail: Always include a strong, rigid cap rail that is securely fastened to all posts. The size should be based on load strength needs
and local code requirements.
Railing Height: Minimum height should be 42" or as set per local code.
Cable Spacing: Maximum three inches apart to allow for cable deflection if ever forced apart.
Wood Blocking: Underneath the cap rail attach minimum 1"x 4" size wood blocking between posts to provide additional lateral reinforcement.
(Wood frames only)
Frame Design Options
Vertical Spacers: Slender spacers may be used instead of some of the larger intermediate posts to
achieve a more open railing design. These are non-structural members and are only intended to maintain cable spacing and
minimize deflection. Use materials such as 2" x 2" wood strips, 1" metal tubing, or ľ" flat bar and attach to the cap
rail and either the foot rail, deck surface, or joists.
Foot Rails: Foot rails are another design option, and they should be spaced no more than four inches above the
deck surface, or as required by local code, and should be sized as needed for support strength and design appearance.
Single Corner Post: Single posts can be used instead of a double corner post configuration. In most cases, however,
cables must be terminated at single corner posts. Exceptions are angle iron posts or tubular metal posts. Corner post details
are discussed in the next section.
Maximum Cable Run Lengths
When a cable passes through posts and around bends, friction is imparted on the line. Running a cable continuously
through too many posts or bends will eventually restrict the ability of the cable fittings to properly tension the line. Therefore,
itís necessary to restrict the length of individual runs to provide the extra adjustment needed to overcome the additional
resistance. Two basic guidelines for ensuring proper cable tensioning are as follows:
- Straight runs should terminate every 50 feet or less.
- Runs with bends should terminate after every 2nd bend or 40 feet, whichever distance is less.
Building codes vary by state, county, and city, so itís important to note that following a manufacturerís recommended
railing design and installation procedures does not necessarily ensure code compliance in all areas. Therefore, before starting a
project, always consult with your building department to see if there are any special local requirements for using and installing
Design & Cable Installation Checklist
Two of the most important code issues relating to cable infill are the 4-inch sphere rule and the restrictions on horizontal infill.
4-Inch Sphere Rule:
In most areas, building codes require that guardrails have intermediate rails, balusters, or ornamental infill patterns that will
not allow passage of a sphere four inches or more in diameter. Since cables are semi-flexible, it is necessary to allow for the
possibility of cable deflection when designing a railing. This is done by spacing the cables and posts (or vertical members)
such that the cables will not open past the four inches of the sphere when a reasonable force is applied. From experience,
manufacturers have been able to determine that when the cables are spaced no more than three inches apart and the posts or
vertical members are spaced no more than three feet apart, one can easily tighten the cable such that they will comply with
the four-inch code rule. These spacing recommendations will apply regardless of the cable diameter being used.
There has been a lot of discussion over the years regarding the safety of horizontal elements in railing designs because
of a perceived climbability issue. In fact, the very first edition of the International Residential Code (IRC) actually
included a restriction on horizontal railings. However, after extensive independent research was conducted and reviewed
by an International Code Council (ICC) code committee, the restriction was removed in the very first IRC supplement
(details of this research are available upon request). The International Building Code (commercial codes) never included
wording that restricted horizontal railing elements.
Some building departments, however, are not yet using the International Code Council (ICC) codes and continue to prohibit
horizontal infill. This is becoming less of an issue as more and more building departments adopt the ICC wording which
allows horizontal infill designs. But, itís always a good idea for architects and installers to check with their local
building officials before starting a project to confirm that there are no restrictions on horizontal infill in their area.