Cable railing: what it costs and what it demands
Cable railing is the most transparent guard you can build and the most demanding to build correctly. The cables must be tensioned hard enough not to spread, which means the posts must be stiff enough to take that tension, which means more posts than a wood railing needs.
The numbers
| Typical range | |
|---|---|
| Material per linear ft | $45–90 |
| Installed per linear ft | $60–120 |
| Max post spacing | 4 ft typical, 5 ft with steel posts |
| Cable diameter | 1/8″ or 3/16″ |
| Cable material | 316 stainless (not 304, near salt water) |
| Cable spacing | Typically 3″ on centre, must keep the 4″ sphere out |
| Tension | 200–400 lb per cable, per the fitting |
Why post spacing drops to four feet
A cable under tension pulls its end posts toward each other. With 12 cables at 300 lb each, a post at the end of a run sees roughly 3,600 lb of horizontal load — far more than a railing post is designed for under the 200 lb code load.
The result is that cable systems specify 4 ft spacing for wood posts and up to 5 ft for steel. On a 48 ft run that is 13 posts instead of 9: four extra holes, four extra footings, four extra post bases. That is the real cost of cable, and it is not in the per-foot price.
The deflection rule people miss
Most codes require that a guard resist a 200 lb load without deflecting more than 3 inches, and that the infill keep a 4″ sphere out. For cable, the second requirement is satisfied by spacing the cables 3″ apart — but only at rest.
Under load, cables spread. A 3″ spacing that opens to 4½″ at the middle of a span is a failed inspection even though the as-built spacing was correct. This is why the fitting hardware, the tension and the post stiffness all have to be right together, and why cable systems are tested as a system rather than assembled from parts.
Where cable makes sense
- A view worth the money. That is the honest reason, and it is a legitimate one.
- A deck that will not be re-finished. Stainless and powder-coated posts need washing, not coating.
- Modern architecture where wood railing would read as heavy.
Where it does not: a deck with children under five (the horizontal cables are climbable, and some jurisdictions restrict them for that reason), a tight budget, or a frame that cannot take four extra posts.
What this guide will not size for you
- It does not size your posts. Cable tension loads are significant and the post and its anchorage need to be designed for them.
- It does not cover the fittings, which vary by system and are not interchangeable.
- It does not address local restrictions on climbable infill, which some jurisdictions apply to cable regardless of spacing.
- It does not include the cost of additional footings in the per-foot figure.
Questions people actually ask
How much does cable railing cost?
Roughly $60–120 per linear foot installed, against $25–45 for wood and $45–75 for aluminum. The premium is partly material and partly the extra posts cable requires.
Why does cable railing need posts every 4 feet?
Because the cables are tensioned to 200–400 lb each, and that tension pulls the posts together. A wood post at 6 ft spacing will deflect under the combined load of 10–12 cables.
Is 304 stainless good enough for cable railing?
Not near salt water. Use 316 stainless, which resists chloride pitting. Inland, 304 is common but 316 lasts longer.
Can cable railing be used where children live?
It can, but horizontal cables are climbable and some jurisdictions restrict them. Check locally before designing around cable, and consider a mesh backing if the deck serves young children.