Cottage Lake Building Safety: Scaffold & Sidewalk Shed Rules (2026)

Scaffold safety in King County is primarily regulated by the Washington Department of Labor and Industries Division of Occupational Safety and Health (DOSH) under WAC 296-874 (Scaffolds, Work Platforms for Construction) and WAC 296-24 (General Safety Standards). These rules are state equivalents of federal OSHA scaffold standards (29 CFR 1926 Subpart L). Scaffolds over 4 feet in general industry and over 10 feet in construction require guardrails, midrails, and toeboards. Fall protection is required at 10 feet for most construction scaffolds. Scaffolds must be designed by a qualified person and erected under competent-person supervision. Scaffolds over 125 feet or suspended scaffolds require engineering design stamped by a Washington-licensed Professional Engineer. Daily inspection is required before each shift. Components must be in good condition — damaged planks, cracked frames, or corroded tubes must be removed from service. Foundations must be sound and level. Electrical power lines must be at least 10 feet clear (more for higher voltages). Workers on scaffolds must be trained. Public protection — including pedestrian walkways under sidewalk bridges, debris netting, and barriers — is required for any scaffold erected over or adjacent to public pedestrian routes. King County requires building permits for scaffolds exceeding certain height thresholds or when erected in public rights-of-way (right-of-way permits). Incorporated cities like Seattle have their own scaffold permit requirements. Dust, noise, and working hour rules for construction sites apply to scaffold work.