As more homeowners gravitate towards modern, high-design concepts, it's no surprise that cable railing systems are taking the outdoor living scene by storm. These sleek deck railing solutions provide homeowners with the luxury of unimpeded sightlines and maximum system durability and strength.

Given the popularity of cable railing systems, we're addressing one of the most frequently asked installation questions: How far apart should the cables be?  Our railing and decking experts break down the answer to this tricky question below.

How far apart should the cables be?

Correct spacing between cables is one of the components of a properly installed railing system. Whether oriented horizontally or vertically, the spacing between all cables is subject to what is known as “sphere rules.” These designations state that a 4-inch sphere cannot pass through an opening in the railing system. However, since the cable is not rigid, the material’s flex should also be considered. For this reason, the industry standard for cable spacing is 3 inches.

Spacing the posts properly

Another important component of cable railing installation is the spacing between posts. Steel, wood, composite or aluminum posts can be used in cable railing systems, each of which has its own thickness specifications. Unless homeowners are using additional support, posts should be no further than 4-feet apart. This is done to ensure cables do not deflect or bow under cable tension loads. By placing posts 4-feet apart homeowners ensure their cables will still meet the 4-inch sphere rule. However, if the design calls for wider spacing, cable railing posts can be spread further apart if they are reinforced with post stiffeners.

Consider the pre-assembled option

To help take the guesswork out of spacing, leading railing manufacturers like Fortress Building Products offer both vertical and horizontal pre-assembled steel cable railing systems. These offerings not only come with easy to modify panel lengths for a simplified installation process, but also only need re-tensioned once, ensuring cable railing spacing stays strong and true. Pre-assembled options, which can accommodate greater spans between posts (Fortress offers 6-foot and 8-foot panels), also provide greater visibility to the view beyond the deck. Not to mention, these systems are compatible with several different post materials like composite, wood and vinyl. This flexibility enables homeowners to achieve the design aesthetic they’re going for without compromising safety on deck. 

While some home improvement projects may seem complex or intimidating, Fortress wants to empower DIYers to tackle all their deck railing projects with confidence. For a quick and straightforward process, check out our railing installation videos.