At what height does a deck, porch, or stair need a guard?
Guards are required where open sides exist more than 30 inches vertically to the floor or grade below (IRC R312.1.1, 2012 edition).
The rule covers open-sided walking surfaces, including stairs, ramps and landings. The 30-inch drop is measured vertically to the floor or grade below at any point within 36 inches horizontally of the edge of the open side.
Insect screening does not count as a guard under this code.
This answer is based on Section R312.1.1 of the 2012 IRC. Section numbers and details can change in later editions and through state or local amendments, so confirm the edition your jurisdiction enforces with your building department before you build.
Related answers
- What height should a stair handrail be? — IRC §R311.7.8.1
- How high should a stair handrail be and what size is actually graspable? — IRC §R311.7.8
- What are the maximum stair riser height and minimum tread depth? — IRC §R311.7.5
- How wide does a staircase have to be? — IRC §R311.7.1
- How tall do guardrails and deck railings need to be? — IRC §R312.1.2
- How far apart can balusters be on a railing? — IRC §R312.1.3
- How much force does a deck guardrail or handrail have to resist? — IRC §R301.5
- How high does a window sill have to be above the floor to meet fall-protection rules? — IRC §R312.2.1
Need this scoped to your jurisdiction?
Adopted edition and local amendments vary by city and county. Ask Donnie checks your jurisdiction and cites the exact adopted section.
Ask Donnie →General information based on the International Residential Code (a model code). This is AI assistance to verify — not legal advice. Confirm the adopted edition and any local amendments with your local building department (AHJ) and a licensed professional before you build.