Stair Railing Building Code Summarized

illustration depicting railing codes for homes

Illustration: © The Spruce, 2018 

When remodeling homes, do-it-yourselfers might keep a loose watch on building code but don't necessarily thumb through the code book at every available minute. Innumerable home projects rarely even touch on building code: painting, floor covering, window replacement, and more. Following logic and informed guesswork can take you a long way with simple projects like this. But other projects such as electrical and plumbing are strictly by-the-book. ​Staircase railing code is the same way.

When you start looking at the stairway code regarding handrails, you begin to see the logic behind it. Code, despite the way it may seem at first, is not an arbitrary thing. For instance, the requirement that handrails be continuous all the way down is common sense. Switching from one rail to another may be just the thing that causes you to lose concentration and fall, mid-switch. Staircase code helps you avoid this.

IRC Stair Railing Code

This guide provides you with highlights of stair handrail code and guard requirements as derived from the 2015 International Residential Code for One-and Two-Family Dwellings and 2015 International Building Code. Because communities often adopt and adapt the model code, you do need to check with your local permitting agency. Staircase railing and guard construction (new or remodel) may also trigger permit requirements.

Be careful to note that some sections of stair railing code must work in conjunction with other sections of stair code. For example, the minimum hand clearance between the railing and the wall that it is mounted on is 1 1/2 inches. Yet if you push out the railing too far, you risk violating another section of code that provides for 27 inches of walking width between a double-railing staircase.

Stair Railing Terminology

One word on terminology: stair railing vs. stair guards. Stair railing runs on the stair incline, up and down. By contrast, stair guards run horizontally along a flat area, with a drop on the other side. Stair guards do not protect stairs but are often used in conjunction with stairs (as with landings, the flat sections within stair inclines).

  • 01 of 06

    Handrail Height: 34 Inches to 38 Inches

    Area Defined: Handrail height is the height of the handrail in relation to the stairs.

    Details: Railing height on stairs should be between 34 and 38 inches. The way you measure this is from the very end of the stair nosing upward completely vertically. Measuring at a different part of the stair tread will give you an inaccurate measurement and may be a code violation.

    Reason: Railing needs to be at a height that can be reached by most people. The 34 inches to 38 inches range will not accommodate all users, but it will cover a large majority of the population. When measuring, be sure to run the tape vertically from the nose (that is, the leading edge) of the stair tread upward to the first point where this vertical line will intersect with railing.

  • 02 of 06

    Maximum Projection of Railing From Wall: 4 1/2 Inches

    Area Defined: Projection from the wall is how far the railing is away from the wall that it is mounted on.

    Details: The outer edge of the railing should not project more than 4 1/2 inches from the wall on which it is mounted.

    Reason: Railing that projects farther than this will crowd the walking path, especially when the opposite railing also projects very far outward. The problem is intensified when the person is carrying large items up or down the stairs and can be a significant safety hazard.

  • 03 of 06

    Minimum Hand Clearance From Wall: 1 1/2 Inches

    Area Defined: Minimum hand clearance means the area between the handrail and the wall. In other words, this is the area where your hand goes.

    Details: Provide at least 1 1/2 inches of clearance between the wall and the railing for easy grasping by the hand. Purchasing handrail brackets ensures that you maintain the perfect distance from the wall.

    Reason: You need to provide the hand with a clear, continuous pathway for the entire length of the railing. Also, while not specified by code, make sure that the handrail brackets do not interfere with hand movement.

  • 04 of 06

    Minimum Railing Distance From Each Other, Two Railings: 27 Inches

    Area Defined: Minimum railing distance for two railings refers to the walking space between two handrails on the same staircase.

    Details: When you have two railings (one on each side of the stairwell) those railings must be at least 27 inches apart from each other.

    Reason: Note that this code requirement works in conjunction with the requirement about ​the maximum projection of railing from the wall. This code is important because it provides for enough room for a person to walk and carry items up or down the stairs.

    Continue to 5 of 6 below.
  • 05 of 06

    Minimum Railing Distance, One Railing: 31 1/2 Inches

    Area Defined: Minimum railing distance means the walking space between a handrail on one wall and an adjacent wall that has no handrail.

    Details: When you have just one railing on a staircase, the outer edge of the railing must be at least 31 1/2 inches away from the wall on the other side of the staircase.

    Reason: When you have only one railing, you have more walking path width available than if you had two railings. The 31 1/2 inches minimum distance provides a full 4 1/2 inches more width than the double railing minimum.

  • 06 of 06

    Guard Railing Minimum Height: 36 Inches

    Area Defined: Guards are the rails that protect people from falling off of high areas, such as landings. Landings can mean intermediary sections within a staircase or terminal sections at the top of a staircase.

    Details: When the drop-off is more than 30 inches down, a guard must be installed on horizontal walking surfaces. The minimum height for this guard is 36 inches.

    Reason: As with exterior decking, no guards or rails are needed if the surface is close enough to the ground: 30 inches or less. The theory is that a person may injure themselves falling off of an 18 inch-high deck, for example, but nowhere near as severely as if they fell 8 feet down. However, if you can add a guard even to surfaces that are lower than 30 inches, so much the better.