Appeal 34829

ORSC R302.1 R302.3 R403.1

Fire-rated exterior walls must be supported by continuous foundation walls with properly sized footings consistent with the structural load path and adjacent grade.

Substitute a continuous foundation wall with a 5/8 Type X GWB-wrapped triple 2x6 wood beam supported by 5/8 Type X GWB-wrapped 4x8 wood beam segments on reinforced piers, preserving utility clearance and meeting fire-rated structural requirements.

Original Appeal Language:
Appeal #2: Pier and Beam Support Instead of Foundation Wall
Code section being appealed:
ORSC R302.1 and R403.1 (Footings), R302.2 (Exterior walls near property lines)
Regulation requirement:
Fire-rated walls must be supported by continuous foundation walls with properly sized footings per the structural load path.
Code modification or alternate requested:
Use of reinforced piers and structural steel beams (C8x10.5), including fire-rated decking, to support a 2" wide firewall in lieu of a continuous foundation wall.
Proposed design:
• Retain and reinforce existing piers.
• Bolt short sections of galvanized C8x10.5 beams to piers.
• Span a continuous galvanized C8x10.5 beam (~13’6.5”) under the firewall.
• Mount a 2" wide fire-rated wall above this beam (¾" plywood + 2 layers ?" Type X + non-combustible cladding).
• Infill 15” between stair stringer and ADU with fire-rated galvanized plate supported on beam and steel angle.
• Maintain utility clearance under assembly.

Reconsideration Text:
Reconsideration Overview:
This reconsideration is submitted in response to the denial of Appeal ID #34808. It applies to the fire-rated wall support assembly associated with Permits 25-027199 and 25-040811, which together govern the stair firewall construction and adjacent structural modifications.
The original appeal was reviewed based on an outdated design involving steel beam supports. This reconsideration provides the correct and current design, which uses a wood beam wrapped in 5/8 Type X GWB, supported by 5/8 Type X GWB wrapped short horizontal 4x8 beam segments attached to support piers, and paired with a horizontal fire-rated steel plate to enclose the utility zone.
Proposed design:
• Retain and reinforce as needed existing piers.
• Support the fire-rated wall on a triple 2x6 beam, fully wrapped in 5/8” Type X gypsum board (GWB) on all exposed sides.
• The beam bears on short horizonal 4x8 beams, also fully wrapped in 5/8” Type X GWB, anchored to existing concrete piers (rear piers enlarged if required).
• Enclose the 15” utility gap between the stair stringer and ADU wall with a galvanized steel plate underlain with 5/8” Type X GWB, supported on the GWB-wrapped triple 2x6 beam on the stair side and a GWB-wrapped 2x6 joist mounted to the ADU foundation. This plate supports the fire-rated wall above and forms part of the continuous fire-rated structural base. All seams are sealed for fire integrity.
• Mount the 2" wide fire-rated wall (¾" plywood + 2 layers ?" Type X + non-combustible cladding) directly atop the plate, anchored to the stair stringer, support posts, and added 2x4 wood framing on the protected side.
• Maintain utility clearance under the assembly.
• All GWB seams are sealed with fire-rated caulking.

• The revised design replaces the steel beam with wood members fully wrapped in 5/8” Type X GWB, maintaining a fire-rated and structurally continuous load path using non-combustible and fire-resistant assemblies.
• GWB-wrapped 4x8 horizontal members provide code-compliant vertical load transfer from the GWB-wrapped triple 2x6 beam to the reinforced concrete piers.
• This configuration avoids disturbing sewer, gas, and water lines between the stair and ADU fire-rated walls, preserving existing and permitted utility alignments.
• The design minimizes tenant disruption and satisfies the intent of ORSC R302 and R403 for structural stability, fire separation, and life safety.