Install a Cable Railing

Railings affect the appearance of a deck more than just about any other design element. But the type of railing you select also affects your view from the deck, your privacy when you’re using the deck and the maintenance your deck will require.

For my deck, I wanted a modern-looking railing that would not obstruct the view of my backyard and that would require very little maintenance. Cable railing turned out to be the perfect choice for me.

This type of railing system uses cables instead of balusters between the posts. It has been used for years in commercial settings, but the increasing interest in modern design and architecture during the past 10 years has made it a more common choice in residential applications, both indoors and outside.

The most obvious benefit of cable railing is that it does not obstruct your view. Most residential cable railings are made with 1/8- or 3/16-in.-dia. stainless steel cables that essentially disappear when you look through them.

The other major benefit of cable railing is that it requires very little maintenance. Wood posts and rails may need to be restained or painted every few years, but cables typically need only occasional cleaning with a damp rag and a seasonal tension adjustment, depending on the rigidity of the frame and temperature extremes in your region.

I chose the CableRail system manufactured by Feeney (see SOURCES in PDF below) because it features cables with integrated threaded terminal fittings as well as QuickConnect-SS fittings that make the installation very simple. The cost varies depending on the length of the run and the number of fittings you need. For example, a 20-ft. run of the CableRail system, consisting of 10 horizontal cables, costs about $22 a foot — comparable to many composite deck-railing systems. If you’re interested in horizontal cable railing for your deck, check with your local building authority to be sure that it is accepted by code in your area.

Compared with popular rigid railing materials, cable poses a unique challenge in that it can be moved or deflected to create larger or smaller openings. The International Residential Code (IRC) requires that a 4-in.-dia. sphere cannot pass through any opening of the railing, so cables must be spaced no more than 3 in. apart and must be under enough tension to keep them from creating larger openings. Use stainless steel cable fasteners and fittings specifically designated for railing applications.

Use exterior-rated lumber for the post-and-rail framing components. I used pressure-treated Southern yellow pine and stained it with a deck stain/sealer.

All framing fasteners and brackets must be corrosion-resistant and compatible with the lumber you plan to use. For example, when using ACQ pressure-treated lumber, use stainless steel fasteners, hot-dipped galvanized coated fasteners or fasteners coated with an ACQ-approved proprietary coating.

The first decision you must make when designing your cable-railing layout is whether you will use separate terminating cables at the corners or a single continuous run of cable (see “Corner Options,” in PDF below). The main advantage to using separate cable runs that terminate at the corners is that you can use a single post in each corner, which means one fewer post and results in a more open appearance. Separate cables can also be a little easier to tighten because of their shorter length. However, a continuous run with a single longer cable costs less than several shorter cables and requires fewer fittings.

The strength of any railing system depends primarily on the strength of the posts and post connections. Use 4x6 lumber for all corner and end posts, as they’ll be supporting all of the cable-tension load. Use 4x4 lumber for all of the other structural intermediate posts and 2x4 posts between the larger posts. The 2x4 posts are not structural; they serve primarily as intermediate supports for the cable. The cable must be supported a minimum of every 36 in. to control deflection.

The posts alone will not resist the several hundred pounds of potential force that is exerted by the tensioned cables, so in addition to a securely fastened 2x6 cap rail, 2x4 or 1x4 horizontal blocking is attached between the posts underneath the cap rail. This blocking provides additional lateral reinforcement so that the posts will not be pulled out of plumb when the cables are tensioned.

Foot rails can also be included in your design to provide additional lateral resistance and to act as a footrest. These rails are optional, however. To create an open appearance, I chose to use them only on the stairs.

Stair railings are designed using the same components and spacing guidelines as the horizontal rails. The only two differences with stair railings are that you must drill the guide holes at an angle to match the stair-tread pitch and you must install a handrail that meets the building code standard for “grippable” or “graspable.” My city requires that the cross-sectional dimension of the handrail must not be less than 1-1/4 in. or more than 2-5/8 in. The handrail must also be at least 1-1/2 in. away from the wall or posts.

The most important aspects of the installation are properly securing the posts and drilling the cable-guide holes. Installing the cable itself is as simple as lacing it through the guide holes and tightening the nuts.

Fasten the posts directly to the deck framing using 1/2-in.-dia. bolts and manufactured brackets. Securely attach the horizontal blocking and cap rails with deck screws. Posts must be spaced at least 3 to 4 in. away from adjacent house siding to provide room for fitting access.

The cable guide holes must be drilled at the same heights and spaced equally. The easiest way to ensure that your guide holes are consistent is to use a template. I made my drilling template using commonly available pegboard. I marked every third peg hole to establish the 3-in. hole spacing and then attached a wood edge to center the holes across a 3-1/2-in.-wide post side.

Use a drill guide to bore the 1/4-in.-dia. pilot holes into the post (photos 1 and 2). Then use a longer 1/4-in.-dia. bit to drill through the post (photo 3). Enlarge each hole as specified by the manufacturer to allow clearance for the cables and fittings you’re using.

Use a drill guide to bore 1/4-in.-dia. cable-guide pilot holes. These pilot holes will act as guides when you use a longer drill bit to bore through the post.

Set the drill guide angle to match the pitch of the stairs. Use the drilling template to bore the angled pilot holes in the stair posts.

Use an extra-long 1/4-in.-dia. bit to bore through the rest of the post. Be careful not to push too hard as the long bit exits the post to eliminate the risk of blowout.

If you are installing multiple cables at the corners, you must offset the cable-guide holes by 1/4 to 1/2 in. This makes one section of cables slightly higher or lower than the adjacent section, but I didn’t think the difference was very noticeable or distracting.

Do your best to keep the holes aligned and straight. Don’t worry if the holes are slightly off track because once all of the cables are in place, their unified appearance will overshadow minor inconsistencies.

The steps for installing the cables will vary slightly depending on the manufacturer, but in a nutshell the steps are as follows: Fasten one end of the cable to a corner post (photo 4), lace the rest of the cable through the posts, secure the loose end with an end fitting (photo 5 and 6), tighten the cables (photos 7, above) and trim the excess cable ends (photos 8 and 9).

Feed the threaded terminal end of the cable through the corner post and fasten it with a washer and nut. Tighten the nut until about 1/4 in. of the threads is exposed.

Feed the loose cable ends through the posts. Secure each cable with a washer and end fitting. Note: Don’t forget the washer. This fitting will not slide off once it is on.

Use a beveled washer fitting at the ends of the angled guide holes. Use protector sleeves where the cable will change direction to prevent cables from compressing the wood around the guide hole.

Tighten the nuts to increase the tension of the cables until they cannot be moved more than 4 in. apart.

Trim the excess cable ends. You can use a heavy-duty cable cutter or hacksaw (photo 8), but I found it easiest to use a cutting wheel attached to a rotary tool (photo 9). Cover the exposed fittings with end caps.

The manufacturer of CableRail includes plastic or stainless steel caps to cover the exposed nuts and end fittings. I chose to use them only on the QuickConnect end fittings that were in inconspicuous locations. I made cover boards to conceal the fittings that were in the most exposed locations.

I considered several railing options, but after a full season of use I couldn’t be happier that I chose to install the cable railing. The horizontal lines complement the long horizontal style of my 1960s ranch-style home, and they provide a great view. It’s like having a window to my backyard without the glass to clean.