Deck Ledger, Guardrail, and Stair Geometry
After a home inspection, Dana contracts with a licensed contractor to replace a 10-by-16-foot deck on her 1978 house in Bend. The new deck is 12 feet above grade at the outer edge. The contractor nails the ledger through the existing T1-11 siding into the rim joist, installs 2-by-8 joists at 24 inches on center, and builds a guardrail with a top rail 34 inches above the deck surface. The balusters are spaced 5-1/2 inches apart. The stair has four risers measuring 7, 7-1/2, 8, and 7 inches. The contractor says no permit is needed because it is a replacement of an existing deck. Dana notices the ledger pulling away and a bounce in the floor. The job is in the city limits and the deck is attached to the house.
1. Identify the Oregon Residential Specialty Code violations in the deck as built.
Read the worked answer
Several features fail the Oregon Residential Specialty Code. The ledger is attached through the siding, so the fasteners are not bearing on the rim joist or band joist as required; the ledger must be attached to the structural framing with approved lag screws or bolts and flashed. The guardrail top is 34 inches, below the 36-inch minimum for a residential guard. The balusters are spaced 5-1/2 inches apart, which allows a 4-inch sphere to pass; the maximum gap must be small enough to reject a 4-inch sphere. The stair has an 8-inch riser, exceeding the 7-3/4-inch maximum, and the variation between adjacent risers (7-1/2 vs. 8) is 1/2 inch, exceeding the 3/8-inch maximum. A permit is required; replacing an existing deck does not exempt the work when it is attached and this high above grade. The bounce and ledger separation are symptoms of the attachment failure.
2. Describe the correct ledger attachment and flashing detail, and the inspection sequence.
Read the worked answer
The correct ledger detail starts by removing the siding or using a standoff that lets the ledger bear directly on the rim joist or band joist. The ledger should be fastened with the approved lag screws or bolts at the spacing required by the code table for the joist span and species, with washers. It must be flashed above and behind the ledger, with a drip edge or membrane that integrates with the weather-resistive barrier, and the siding should be held above the flashing. Joist hangers should be used at the ledger. The inspection sequence is typically footing/foundation, then framing including the ledger attachment and flashing before decking hides it, then final. The contractor should stop work, get a permit, and have the ledger corrected and inspected. Dana should not accept a cosmetic fix.
3. What fall-protection and temporary guardrail obligations applied during construction?
Read the worked answer
During construction, the crew was exposed to a fall hazard well above any Oregon OSHA trigger. The contractor needed a fall-protection system: temporary guardrails on all open sides, personal fall arrest, or a combination, and the system had to be installed before employees worked near the edge. The finished guardrail cannot be used as temporary fall protection before it is complete and inspected. Ladders and stairs also needed safe access, and the site should have been kept clear. The contractor should have a written fall-protection plan, train workers, and inspect the system daily. Dana can report the unsafe work to Oregon OSHA. The lack of temporary guards is separate from the code violations and supports a safety complaint.