Finishing a deck that sits 4 feet above grade.

What the inspector will likely flag:

1. Guardrail height – 34" is too short. IRC R302.1 requires guards on decks 4 inches above grade (and higher) to be minimum 36" high measured vertically above the horizontal projection of the deck surface. Your 34" rail is 2" short.

1. 8" gap between deck boards and bottom rail – potential climb hazard. IRC R302.1 also requires that guardrails prevent a 4-inch sphere from passing through (for residential decks). An 8" gap exceeds this and could allow a child to slip through or use the space to climb.

1. Picket spacing – 5" clear is acceptable. IRC R302.1 requires balusters to be spaced so a 4-inch sphere cannot pass. Your 5" spacing is compliant.

Summary of violations:

• Guardrail height: 34" → must be 36"
• Gap between deck and bottom rail: 8" → must be ≤4"

Fixes:

• Add a 2" extension to the top of the rail or install a taller rail system.
• Install a 4" wide board or additional baluster directly under the deck boards to close the 8" gap.

If the deck is in a jurisdiction that has adopted the IRC, these are clear code violations. If it's a local code with different requirements, check with the AHJ, but IRC is the standard baseline.

Three code violations (IRC 2021/2024 R312):

1. Guard Height: 34" is too low. Minimum is 36" above the walking surface (R312.1.2). Since the deck is 48" above grade, a guard is required (R312.1.1), and it must be 36" min.
2. Picket Spacing: 5" clear opening violates the 4" sphere rule (R312.1.3). Maximum clear space is <4".
3. Bottom Rail Gap: 8" gap between deck boards and bottom rail violates the 4" sphere rule at the stair/deck intersection (R312.1.3). The triangle formed by the riser, tread, and bottom rail must also reject a 6" sphere (R312.1.3, Ex. 1), but the 4" sphere applies everywhere else.

Fixes required before final:

• Raise top rail to 36" minimum (add cap rail or rebuild posts).
• Re-space pickets to ≤ 3-7/8" clear (typically 4-1/2" O.C. for 2x2s).
• Lower bottom rail or add a 2x4 "toe board" to close gap to <4" above decking.

Pro Tip: If this is a stair guard, the height minimum is 34