What are the building code requirements for deck railings in Oregon?

Under the Oregon Residential Specialty Code, a deck needs guards where its walking surface is more than 30 inches above the floor or grade below, measured at any point within 36 inches horizontally. Required guards must be at least 36 inches high, and their openings must not let a 4-inch sphere pass through.

At what height does a deck need a railing in Oregon?

When the walking surface is more than 30 inches above the floor or grade below at any point within 36 inches horizontally of its open side. That is the same 30-inch line that decides whether a deck needs a building permit.

How tall do deck stair handrails have to be?

The code requires a handrail on at least one side of any flight of stairs with four or more risers. Handrail height and grip sizes have their own rules in the code's stair section, so ask the contractor or permit office for the figures that apply to your stairs.

Deck Railing Height Code in Oregon: Guards, Stairs and Gaps

Short answer: in Oregon, a deck needs a railing, which the code calls a guard, once its walking surface is more than 30 inches above the ground or floor below. The guard must be at least 36 inches high, and nothing in it may have a gap a 4-inch sphere can pass through. Stairs with four or more risers need a handrail on at least one side.

These rules come from the 2023 Oregon Residential Specialty Code (ORSC), the statewide code for houses and their decks. The quotes below are from that edition.

When a deck needs a guard

The ORSC requires guards on open-sided walking surfaces that are:

“…located more than 30 inches (762 mm) measured vertically to the floor or grade below at any point within 36 inches (914 mm) horizontally…” (R312.1.1)

Two details matter. The height is measured to whatever is below at any point within 36 inches of the edge, so on a slope it is the lowest point within that band that counts. And the same 30-inch line decides whether a deck needs a building permit: in Oregon, a deck whose walking surface is no more than 30 inches above grade, measured within 3 feet, is exempt. Our guide to deck permit rules covers that side of it.

The deck section of the code ties the two together: exterior deck guards “shall be constructed to meet the requirements of Sections R301.5 and R312” (R507.10), so a deck guard has to be built to carry the code’s loads, not just be tall enough.

How high a deck railing must be

“Required guards at open-sided walking surfaces, including stairs, porches, balconies or landings, shall be not less than 36 inches (914 mm) in height…” (R312.1.2)

The 36 inches is measured from the walking surface, and it is a minimum: a guard can be higher than the code requires, never lower.

The 4-inch gap rule

“…shall not have openings from the walking surface to the required guard height that allow passage of a sphere 4 inches (102 mm) in diameter.” (R312.1.3)

That applies to the spaces between balusters, the gap between the deck surface and the bottom rail, and the openings in cable, wire-panel or glass infill. If a 4-inch ball fits through anywhere below the required guard height, the guard does not comply.

Guard posts

The American Wood Council’s prescriptive deck construction guide (DCA 6, based on the 2015 model code) says deck guard posts for required guards “shall be a minimum 4x4 (nominal) with an adjusted bending design value not less than 1,100 psi.” Where the guide and the code differ, it says, the code applies.

Deck stairs

Stairs off a deck are covered by the same stair rules as any other stairway. From the 2023 ORSC:

Width: “Stairways shall be not less than 36 inches (914 mm) in clear width at all points above the permitted handrail height…” (R311.7.1)
Risers: “The riser height shall be not more than 8 inches (203 mm).” (R311.7.5.1)
Treads: “The tread depth shall be not less than 9 inches (229 mm).” (R311.7.5.2)
Handrails: “Handrails shall be provided on not less than one side of each flight of stairs with four or more risers.” (R311.7.8)
Guards on stairs: the 36-inch guard rule above names stairs too, wherever the open side of the stair is more than 30 inches above the grade below.

The 2026 code

Oregon’s 2026 edition of the ORSC took effect on October 1, 2026. Apart from Chapter 1, it has a six-month phase-in: until the 2026 code becomes mandatory on April 1, 2027, the Building Codes Division permits use of either the 2023 or the 2026 ORSC. The section numbers and wording here are from the 2023 edition, because the integrated 2026 book had not been published when we checked on October 9, 2026.

Getting it right

These are the code’s minimums, quoted as published, not a design. If a railing on your deck wobbles, has gaps a 4-inch ball would pass, or is missing where the deck is high, see deck repair and replacement. A local deck contractor can quote new guards or stairs for free.

This page is general information, not professional advice about your specific situation. Have it assessed by a qualified professional before making decisions. Last reviewed October 9, 2026.