Balustrade and Railing Building Code

The 4" Sphere Space Requirement Rule

The 4" Sphere Rule gives the maximum center-to-center distance between Balusters and still does not allow a 4" sphere to pass through at any point beteen the Balusters.

When laying out Balusters, use the maximum center to dimension or smaller to allow for a safe dimension to pass the 4" sphere space requirement rule.

Minimum Height Requirements

The minimum height requirement states that the balustrade system must be a certain height from the floor to the highest point of the top rail. The residential height requirement is 36" and the commmercial height requirement is 44".

Building Code varies from county to county. Consult your local agency responsible for regulating building code for more specific code information.