School District Acoustical Upgrade

The Problem

A K-8 school in the Elk Grove area had classrooms built in the early 1980s with original ceiling tiles that had long passed their useful life. Teachers reported that students in the back rows couldn't hear clearly, and the cafeteria was so loud during lunch that staff had to shout. The gymnasium had bare exposed structure with no acoustic treatment at all — every bounce of a basketball echoed for seconds.

The district had funding from a modernization bond and wanted to address acoustics across the campus in one summer. The work had to be DSA-approved (Division of the State Architect), which means plan review, inspections, and specific material requirements that go beyond standard commercial specs.

Our Approach

We worked with the district's architect to develop a DSA-compliant scope that addressed each space differently based on its acoustic needs. Classrooms needed speech intelligibility — the teacher's voice has to reach every seat clearly. The cafeteria needed overall noise reduction. The gym needed sound absorption to tame the reverberation.

The entire project was scheduled for a 6-week summer window between the last day of school and teacher prep week. That's a hard deadline — if the ceiling isn't done when teachers come back, the district has a problem. We staffed two crews to run classrooms and the cafeteria simultaneously, then shifted both crews to the gym for the final two weeks.

Products Used

Classrooms: Armstrong School Zone tiles — specifically designed for education spaces. NRC 0.70, high light reflectance (0.90), and a durable, cleanable face that holds up to the abuse a classroom dish out. We installed on new 15/16" grid with seismic clips per California code.

Cafeteria: Same grid system but with Armstrong Ultima HPC (High Performance Ceiling) panels. NRC 0.70, humidity-resistant face, and CAC 35 to reduce noise transmission to the adjacent kitchen. We added felt wall panels on two walls to catch the mid- and high-frequency reflections that make cafeterias unbearable.

Gymnasium: The gym got Armstrong Soundscape baffles — 48 baffles hung from the roof structure in a grid pattern. NRC 0.90 per baffle, and because they're exposed on both sides, the total absorption is significant. We used the Natural color to blend with the structure. Baffles were hung on aircraft cable with seismic-rated connections.

Challenges

DSA projects have a specific inspection process. The inspector reviewed our grid layout, hanger wire spacing, and seismic bracing before we could install tiles. That means the grid goes up, we wait for inspection, then tiles go in. On a tight summer schedule, any delay in the inspection can push the whole project. We submitted our shop drawings early and had the inspector scheduled in advance for each phase.

The gym was the trickiest space. The roof structure was exposed steel bar joists at 32 feet — meaning every baffle hung on 30+ feet of aircraft cable. The rigging had to account for seismic forces on those long hangers. We used lateral bracing cables to prevent the baffles from swinging in an earthquake, which is a California-specific requirement that doesn't exist in most other states.

Above-ceiling conditions in the classrooms were messy. Old wiring, abandoned HVAC runs, and leftover debris from the original construction. We coordinated with the electrician to remove abandoned conduit and capped off old ductwork so the new ceiling would sit flat.

Results

All work was completed 3 days before the deadline. The district's acoustical consultant measured speech intelligibility in the classrooms post-installation and found STI (Speech Transmission Index) scores improved from 0.48 (poor) to 0.72 (good). Teachers could speak at a normal volume and be heard in the back row.

The cafeteria went from a space where you couldn't have a conversation at normal volume to one where the noise level during lunch dropped by an estimated 8-10 dB. That's roughly cutting the perceived loudness in half.

The gym baffles transformed the space. The RT60 (reverberation time) dropped from over 4 seconds to under 1.5 seconds. PE teachers could give instructions without shouting, and the space was usable for assemblies and events without a sound system fighting the echo.

Key Takeaways

• Education projects need speech intelligibility as the primary acoustic goal
• DSA approval adds time — build it into the schedule upfront
• Gym baffles are the most effective solution for high-ceiling athletic spaces
• Summer schedules are tight — two crews and pre-scheduled inspections keep you on track
• Wall panels in cafeterias work with ceiling tiles to control noise from multiple directions