Decks

Residential decks may be permitted and constructed without structural engineering for design. Conventional light framing rules may be used as a guide for their construction. Decks less than 30 inches above grade may not require a permit. All gravity loads, spans, and connections shall be within the stated code minimums.

Oregon Residential Specialty Code (ORSC) R502.2.2

• A structural ledger shall be attached to the structure and the connection verified, or the deck shall be supported on all sides. (Freestanding)
• Columns shall have an le/d (length to least thickness) ratio of less than 50 per Chapter 16, International Building Code (IBC). 4 by 4 post would be allowed to be 14 feet between points of lateral support. Any taller will require an engineered design.
• Deck lateral load connections shall be performed by hold-down tension devices as per section ORSC R502.2.3.
• Footings shall be sized for their loads @ 60 PSF of area (minimum 18 inches diameter or equal) and embedment (minimum 12 inches below grade). Note that footings on steep slopes as defined by Article 13 of the Grants Pass Development Code (PDF) or ORSC R403.1.9.4 shall be per an approved geotechnical report and design.
• Guardrails are per ORSC R312 - Minimum 36 inches high with openings less than 4 inches if over 30 inches above grade.
• Lateral bracing may be accomplished by several methods:
  • Attachment to an adjacent rigid structural member (e.g. a structural wall.)
  • Appropriately attached knee or diagonal braces of 2X material (or greater) at all post/beam connections. (Note: diagonal braces should be required to span as large a space as is practical from post/beam connections.) See ORSC figure R502.9 for requirements.
• Ledgers shall be attached to the building when supporting the deck with anchors per ORSC table R502.2.2.1.
• Posts and main members may be required to be resistant to decay or be pressure treated per ORSC R317.
• Requires a positive connection to the primary structure (exterior wall or rim joist) not using toenails or nails subject to withdrawal.
• Standard Simpson-type hardware and the nailing/fastener schedule Table R602.3 shall be considered sufficient to resist uplift at major connections.

This policy does not apply to commercial or multifamily structures or residential decks that are integral to a supported roof assembly. For further information on the construction of a deck or to determine whether your project requires structural engineering and/or a permit, please contact the City of Grants Pass Building Division.