Case Study: Powell Hall Catwalk System

Safer OSHA-compliant access above a 1925 landmark—while preserving the historic ceiling. 

Design-Build Retrofit for Historic Venue Access

As part of Powell Hall’s multi-year renovation and expansion, the St. Louis Symphony Orchestra  (SLSO) needed modern, OSHA-compliant access above the 1925 decorative ceiling to support upgraded lighting and ongoing maintenance. We delivered a design-build solution: analyzed the existing roof structure, engineered a new hanging catwalk system, and installed it while working entirely from the roof trusses so the decorative plaster ceiling below remained untouched.

The Challenge

• Historic material everywhere. The decorative ceiling is suspended from century-old cables; any new work had to avoid bearing on that system.

• Non-compliant, risky access. Access lacked handrails, featured walkways that narrowed from four planks to two without signage or railings, and included steep grades—making it unsafe for today’s crews. The goal: modern, OSHA-compliant access for lighting and tech crews.

• Tight logistics. There was no direct path into the attic space; all materials had to come through a small exterior window.

Our Approach: Engineered Precision

We started with engineering. Anvil Engineering verified the roof truss capacities to ensure they could safely bear the weight of the new suspended catwalk system. Our partners at Scaffold Engineering collaborated closely with us to model the permanent hanging system and define the load paths. With the design in place, our crew installed header steel on the existing trusses and we partnered with Brock Industrial Group to hang the catwalk framing from the headers, creating a floating system that never touches the historic plaster ceiling. 

To solve the tight logistics, we built an exterior scaffold platform and used a powered hoist to feed steel and deck through a small window opening. We performed the installation and partnered on the scaffold-based components to keep the construction process smooth and safe from start to finish.

What We Built

• Continuous walkways with OSHA-compliant stairs, handrails on both sides, and durable aluminum decking replacing narrow wood planks.

• Layout was adjusted to raise the system above new LED lighting and avoid conflicts with existing ceiling support cables, which were flagged with safety orange for visibility and crew safety.

Safety + Execution

• 3,100 work hours, daily JSAs, and zero injuries.

• Work sequencing and temporary platforms kept crews off fragile surfaces and out of the historic ceiling system.

The Outcome: Safe, Permanent Catwalk with Full Compliance

The retrofit delivers OSHA-compliant access for lighting and tech teams with real stairs, handrails on both sides, and durable, lightweight aluminum decking in place of narrow planks. The layout threads around existing light bars and the ceiling support cables, preserving sightlines and protecting the historic fabric. All loads are carried by the original roof trusses through the new header steel, so the decorative ceiling remains untouched, and the SLSO crew now has reliable, safe access.