Railing code in Georgia, in plain English

Railing code isn't red tape — it's the difference between a guardrail and a decoration. Georgia builds on the International Residential Code (IRC) with state amendments, and these are the rules that come up on nearly every railing project we quote.

When is a guard required at all?

Any walking surface — deck, porch, landing, retaining-wall walkway — that sits more than 30 inches above the ground (measured within 36 inches horizontally of the edge) requires a guard. Below 30 inches, a railing is optional; above it, it's the law. That “measured within 36 inches” detail matters on sloped yards: a deck that's 24 inches high at the house can still need guards where the grade falls away.

How tall does it have to be?

• Residential guards: minimum 36 inches from the walking surface to the top of the guard.
• Guards along stairs: minimum 34 inches, measured vertically from the tread nosings.
• Commercial / multi-family (IBC): minimum 42 inches — restaurants, offices, apartment common areas.

We build residential guards at 36 or 42 inches depending on the look the owner wants; taller is always allowed.

The 4-inch sphere rule

The most famous rule in railing: a 4-inch sphere must not pass through any opening in a guard. It exists to keep a toddler's body from slipping through. Practical consequences:

• Pickets are typically spaced at 4 inches on center for ½-inch stock — leaving about a 3½-inch clear gap.
• The gap between the deck surface and the bottom rail counts too.
• On stair guards, the triangle formed by the tread, riser, and bottom rail may not pass a 6-inch sphere.
• Cable railing must meet the 4-inch rule with the cables deflected — which is why cable spacing and tension are engineering decisions, not aesthetics.

Handrails are not guards

A guard keeps you from falling off the edge. A handrail is the thing your hand wraps around on stairs — and stairs with four or more risers require one. Handrail rules:

• Height between 34 and 38 inches above the tread nosings.
• It must be graspable: a round profile of 1¼–2 inches in diameter (or an equivalent shaped profile). A flat 2×6 cap looks nice but doesn't qualify as the handrail on stairs.
• It must be continuous along the flight and return to a post or wall at the ends, so a cuff or bag strap can't snag on an open end.

On metal stairs we usually integrate a graspable rail into the guard design so it reads as one piece — a detailing problem we enjoy solving.

The loads nobody sees

Code requires a guard to resist a 200-pound concentrated load applied at any point along the top, in any direction, and the infill to resist 50 pounds on a one-square-foot area. This is where fabricated steel railing quietly outclasses off-the-shelf systems: the strength lives in the posts and how they anchor. A beautiful railing on weak post anchors is a code failure waiting for a party.

Permits and inspections

New decks, structural stairs, canopies, and most exterior guard work around Senoia and Coweta County require a permit; a like-for-like railing replacement often doesn't — but the finished work still has to meet code, and it will absolutely come up at the home inspection when you sell. When in doubt, a phone call to the local building department settles it in five minutes, and we're happy to make that call as part of the project.

This guide summarizes commonly adopted IRC/IBC provisions as an orientation, not a substitute for the code itself. Local amendments vary by jurisdiction — always confirm requirements with your local building official.