Optional deck railings and the Code

Q. I'm building a deck that's less than 30 inches above grade, so a guardrail isn’t required by our local building code. However, the owner on this project wants the deck to have a railing for aesthetic reasons. If a guardrail isn't required by code and I install a railing anyway, does the railing still have to comply with all the elements of the code (minimum height, live load, infill spacing, and so on), or can I just install a decorative railing that looks good but that may or may not meet code requirements?

A. Chuck Bajnai, Chief Residential Plan Reviewer in Chesterfield County, Va., responds:Guards (also called guardrails or guard systems) are required to prevent someone from falling off an open-sided, elevated surface, such as the walking surface of a deck. When the walking surface is more than 30 inches high, measured vertically from a point 36 inches from the edge of the deck, a guard is required by code to prevent serious injury. (The reason for the 36-inch extension is to prevent folks from piling up mulch at the edge of the deck to avoid installing a guard.)

Whenever your local building code does not require something, anything above nil is acceptable, based on the simple fact that your AHJ has authority only for compliance over matters that are contained within the code. Since there are no requirements in the IRC for guards adjacent to open-sided walkways with less than 30 inches to grade, anything is permissible--with a couple of caveats.

If you’re installing a proprietary, manufactured guardrail system, the code requires that the manufacturer’s installation instructions be followed for liability issues. If a guard system fails, resulting in an injury, and the guard manufacturer’s instructions say to use 1/2-inch-diameter bolts while you’ve used 3/8-inch-diameter lag screws, a judge would not likely rule in your favor should there be a lawsuit.

Also, keep in mind that not every state or jurisdiction adopts the code as published by ICC. For example, Virginia replaces Chapter 1 of the IRC and rewrites it in its entirety, so it’s possible that some states have different requirements for railings. As always, when in doubt, it’s best to check with your local code official. The building official should recommend that the homeowners do "the right thing" and follow best practices in the industry, but probably cannot enforce it.