Since expansive views are common where I build decks, I'm
frequently asked about railings that won't obstruct those views.
Two materials that work well are cable and glass, but because of
the maintenance required to keep exterior glass clean, most of my
clients choose cable.
Before I discuss the installation of cable railings, I'll offer a
couple of words of caution. Check with the local building authority
before suggesting them to your clients, as some jurisdictions don't
allow horizontal railings. The concern is the potential for people,
particularly children, to climb over them. Although some in the
industry disagree, I think this concern is valid and I make my
clients aware of it (especially if small children may use the
deck); on occasion a client has opted not to use cable railings
because of this issue.
Most of the decks I build are constructed primarily of wood,
including the decking and the railing frames. While there are other
options, including aluminum and steel frames, this article focuses
on building a solid wood frame to support the cable.
Keep Cable From Sagging
I've adapted my standard railing design for use with cable, which
interacts with the wood frame differently than other railing
materials do. For one, because making the cables taut places a
great deal of tension on the end posts, I use larger posts and
insert sub-rails between them under the cap rail (Figure 1).
Figure 1. Cable railings exert considerable tension on the end
posts. The solution is to use beefier end posts and fill in between
them with sub-rails.
Another concern with cables is that they can wear away the wood on
the inside of the holes they run through, especially at angle
changes and corners. To protect the wood, cable-railing
manufacturers supply fairly inconspicuous sleeves to line the holes
(Figure 2). Without them, the holes would soon get larger, allowing
the cables to loosen and sag.
Figure 2. Where cables turn a corner or change angle for a
stair, liners are used to prevent the cable from wearing down the
Finally, cables are very flexible, so they need to be supported
more frequently than wood members to prevent sagging. I accomplish
this by adding a vertical component whose only function is to
maintain the cables' horizontal spacing (Figure 3).
Figure 3. Even though cables are tensioned, they can sag
mid-span. A lighter-duty member is used between the posts to
maintain cable spacing.
Ordering Cable Railing
I use Feeney's almost foolproof system to simplify installation.
The manufacturer does the hard work of attaching the threaded
adjuster to one end of the cable (Figure 4). The other end will be
held in place by a quick-connect fitting that allows the cable to
feed through in one direction, but grips the cable tightly when
tension is applied in the other direction. Feeney also sells tools
for working with cable, such as drill bits and cutters. Stainless
steel cable is too tough for normal wire cutters, even the large
ones electricians use to cut service entrance cable.
Figure 4. The system used by the author comes with the threaded
adjuster already attached to one end of the cable.
The one disadvantage to this system is that you have to be precise
when ordering lengths of cable, so you need to figure out the
layout in advance. Feeney's cables come in 5-foot increments, up to
a maximum length of 70 feet for the 1/8-inch cable I use. A large
deck may have more than 70 feet of railing; in that case, you'll
also need to know the starting and ending points of each cable run
when ordering. Be aware that some suppliers limit their cable runs
to even less than 70 feet. The reasoning behind such limits is that
the longer the cable, the harder it is to make it as taut as
required, and the more tension it exerts on the end posts and their
fittings; plus, different end connectors have different limits as
to how much they can be tightened.
Once you've determined the lengths of the cable runs, you need to
figure out the number of cables required for the height of your
railing. The International Residential Code (IRC) says that a
4-inch sphere cannot pass between the cables; most manufacturers
recommend placing the cables every 3 inches - rather than every 4
inches - to ensure that a railing meets that requirement, because
no matter how tight the cable is, there will always be some play in
the center of the run, and over time the cables will stretch,
allowing even more sag.
On the deck shown here, the cable run was 53 feet, and I ordered
nine 55-foot 1/8-inch cable assemblies. Each assembly comes
complete with all the necessary hardware. The only additional items
that I order are stainless steel end caps - instead of the colored
plastic caps that are included in the basic assembly (Figure
Figure 5. One upgrade the author chooses is stainless steel
caps, rather than plastic ones, to conceal the cable
Putting the Wood Frame Together
I begin the installation with the backbone of any railing system -
the posts. I place them outside the deck framework, for a few
reasons; one is so that I can space the posts evenly regardless of
the joist layout. Also, posts mounted this way visually break up
the continuous band of 2x12 I use for a fascia and rim joist.
Another benefit is that I don't need to notch the decking around
With most cable systems, a 4x6 post is required at the end of each
run, and intermediate posts can be 4x4s. Maximum spacing of the
posts is generally 6 feet. In addition, intermediate supports are
needed to prevent the cable from sagging. These can be additional
posts, 2x4s, 2x2s, or even 1x2s. In this case, I used 2x2s. I have
used 2x4s in the past.
I cut all the posts to length and bevel their bottoms at 45 degrees
to soften the look. Then I line them up, mark the bolt holes, and
snap a chalk line 36 inches from their tops to represent where the
posts set in relation to the top of the framing. Before putting the
posts in place, I drill them for mounting bolts, leaving a couple
of posts undrilled in case I have to change the bolt pattern to
avoid a framing member. Next, I partially drive a couple of screws
on the chalk line to aid in placing the posts at the correct
I tack up the end posts first, usually around 2 inches from the
corners. While one worker plumbs the post, another adds a couple of
screws from the inside of the fascia to temporarily hold the post
in place. Once the outside posts are tacked up, I measure the
center-to-center length and determine the spacing for the rest of
the posts, remembering to keep it 6 feet or less. I mark the
spacing and plumb guidelines on the fascia and put up the remaining
posts, making sure the bolt-hole alignment works with the
In the old days, I just bolted the posts to the fascia. I have not
heard of any of the railings I installed in that manner failing,
but since building departments are placing a greater emphasis on
post attachment these days, I have altered my method.
My current approach is to tie the posts and fascias to the joists
and beams using hot-dipped-galvanized threaded rods (Figure 6).
This solution has not been engineered, but the building departments
I've worked with haven't had a problem with it. Where the fascia is
parallel to the joists, I add the rod through one or two joists
with nuts and washers on all sides. Where the fascia is
perpendicular to the joists, I add the rod through the beam, or
through solid blocking if the joist size prohibits me from going
through the beam. By adjusting the nuts, I get a very solid post,
Figure 6. Posts are anchored to the framing with 1/2-inch
galvanized threaded rod.
Once the posts are bolted on, I finish laying the decking to
provide a nice surface to work on. After that, I mark two wood
rails to the same length, measured between the posts at decking
level. One is the bottom rail, and the other is the sub-rail, which
is primarily a long block between the tops of the posts; it gets
installed first and helps insure the posts will be plumb. I use a
Kreg Jig (Kreg Tool; 800/447-8638, kregtool.com) to make pocket holes in
it (Figure 7), for a strong connection to the posts.
Figure 7. Sub-rails are attached to the posts with pocket
Next, I cut the bottom rail 1/2 inch shorter to accommodate
Deckorators (Universal Forest Products; 800/332-5724, ufpi.com/product/deckorators/index.htm)
rail connectors (Figure 8). I also notch it in the center for the
2x2 intermediate cable support (Figure 9). The notch - easily made
with a sliding miter saw set to the proper depth - prevents the 2x2
from rotating; and a 4 1/2-inch HeadLok screw (FastenMaster;
800/518-3569, fastenmaster.com) through the
underside of the bottom rail into the 2x2 secures it in place. (I
love these screws and always have various lengths available on
every project.) Then I use the Deckorators rail connectors to
attach the bottom rails to the posts - usually 3 1/2 inches above
the deck. I plumb the 2x2 and screw a 3-inch deck screw down into
it from the top of the sub-rail. I fasten the cap rail last, which
for appearance is usually the same material as the decking, though
Figure 8. The author uses Deckorators railing connectors to anchor
the bottom rail.
Figure 9. The bottom rail is notched to receive the
intermediate members that maintain the cable spacing.
Running the Cable
I drill the holes for the cable in the posts and intermediate
supports using a 2x4 template that's cut to fit between the rails
and drilled to space the cables evenly and as close to 3 inches
apart as possible (Figure 10). Clamp the template to the post, and
using a 1/4-inch bit for 1/8-inch cable, drill the holes straight
and level. If you have trouble, drill partway through, then move
the template to the other side of the post and drill back to
connect the holes. The second approach takes more time, but it also
Figure 10. Using a 2x4 template, drill holes in the posts 3
inches apart for the cable to run through.
The posts at either end of the cable run are treated a little
differently from the intermediate ones. In the post at the start of
the run, you'll need to drill larger-diameter holes to accommodate
threaded terminal rods. At the other end of the run, you'll need to
countersink the holes for quick-connect fittings.
After all the posts are done, add a piece of scrap as a stop on the
template to allow you to use it to drill the 2x2s. In this case, I
added a 1-inch ripping to the edge of the template.
Wherever you change directions with the cable, whether for stair
angles or changes in the railing direction, you will need to use
protector sleeves to prevent the cable from digging into the wood.
It's easiest to put them in as you string the cable; if you put
them in prior to running the cable, you'll undoubtedly run the
cable into the sleeves' edges and knock them out. Just be sure not
to forget them.
Now it's time to string the cable. I start at the bottom, but you
could start at the top as well. The cable comes rolled in a coil.
Stretch out one line at a time, and if you have multiple lengths
make sure you grab the right one. One end of the cable comes with a
threaded rod attached; the other end is bare cable. Insert the
threaded rod into the end post, from the cable side (Figure 11).
Allow enough rod to stick out beyond the post to enable you to put
on the washer and nut (Figure 12). You'll tighten the nuts
Figure 11. Begin running the cable by inserting the threaded
end through an end post.
Figure 12. Make sure enough thread protrudes to start a nut and
Feed the loose end of the cable through the other posts and the
intermediate supports. When you come to an angle change, pass the
cable through the hole in the post, slip a protector sleeve over
the cable, and tap it into the hole. Continue stringing the cable
through the holes, making sure you are in the correct hole each
Hopefully, you will have a little extra cable when you reach the
last post. Take a moment and look around. This is the last chance
to make sure the last hole is countersunk for the quick-connect
fitting and that the cable runs through all the correct holes
before you install the permanent quick-connect end fitting.
Double-check that you've added protector sleeves wherever
Once you're confident, push the cable through that last post. Six
inches through the post is plenty; if you have more, you might want
to cut off the excess. Push the end of the cable through the
quick-connect fitting. The cable will slide right through, but you
will not be able to pull it back out of the connector. Tap the
connector into your countersunk hole and pull the cable tight.
Repeat this process with the rest of the cables - one at a time, so
as not to get confused about which cable goes in which hole.
Tightening the Cables
This is the finish line. All the cables have been strung, and it's
time to tighten them. Grab a loose end with a pair of locking
pliers, and with a scrap of wood between the pliers and the post,
lever the pliers to pull the cable as tight as you can (Figure 13).
If the run is a long one, or there are corners, have someone else
pulling with locking pliers along the way. When you have pulled out
as much slack as you can, cut the cable as close to the connector
as possible (Figure 14). Later, this will allow you to tap the end
cap over the connector and the wire. Repeat the process with the
Figure 13. Use locking pliers and a fulcrum made from a scrap
block to tension the cables initially.
Figure 14. After tightening the cable as much as possible with
the locking pliers, trim the end as close to the anchor as
Go back to the start of the cable run, and tighten the nuts to
remove all the slack (Figure 15). Start with the cable at the
midpoint in your railing height, and alternate cables above and
below the center cable. You'll probably need your locking pliers on
the other side of the post to keep the cable stud from twisting. If
you have a 4-inch sphere available, try to pass it through the
midpoint of the cable run - if you can't, you're good to go. And if
you "play the guitar" on the cables, they should all play the same
Figure 15. Go back to where you started and finish tensioning
the cables by tightening the nuts.
All that's left is to install the caps. You'll have to cut off any
threads exposed beyond the nut. A reciprocating saw with a
metal-cutting blade works fine for this. Tap the caps on and you're
I return to the site later, after the posts have shrunk and the
cable has stretched, to re-tension the cable. Pop the caps off the
rod end with a screwdriver. A slight turn of the nut should be all
that's necessary to retighten the cable.
Mark Ellis owns Creative Redwood Designs in
Los Gatos, Calif.