Spacing requirements for you iron railing
How large can the gaps be in your iron railing? This is especially important to consider if you are looking to install cable railing or another minimalist style of railing.The most common railing code enforces the 4” Sphere Rule, which prohibits gaps in railing large enough for a sphere 4” in diameter to fit through. This ensures that a child’s head will not fit between the railing.
If you are using balusters or glass panels in your iron railing, the 4” Sphere Rule should be simple to accommodate. Just ensure your gaps are less than 4” wide. However, accommodating the 4” Sphere Rule can be more tricky when using a material like cable, which is a bit flexible and can deflect slightly if pulled on.
For cable iron railing, we recommend that each cable be spaced 3 ⅛” apart to ensure a 4” gap remains at all times, even with slight deflection of the cable. To help with this, we also recommend that posts be no more than 4’ apart, which reduces the ability of the cable to deflect. If your posts must be spaced further than 4’ apart, you may need an intermediate post to stop the cable from deflecting too much.
Contact your code official to find out if your county enforces the 4” Sphere Rule, and if you need to be aware of any other spacing requirements unique to your region.