Practical Tips for Specifying Acoustic Materials in Building Design

Good acoustics start with good specs. Whether you’re designing a new facility or renovating an existing space, the materials you choose can make or break the project’s sound performance. Doors, walls, and their components all contribute to how well a space can block or absorb unwanted noise — and that means architects and specifiers need to understand what goes into making the right call.

STC Ratings: What They Mean in Practice

Sound Transmission Class (STC) ratings are the most widely used measure of how well a door or wall reduces airborne sound. Higher STC ratings generally mean better performance, but context matters. For example, a solid-core wood door with an STC rating of 34 may block normal conversation — but not louder noise. To block louder speech or protect privacy, a door system may need to reach STC 40 or higher.

What Affects a Door’s STC Rating?

Several factors work together to achieve an STC rating:

  • Core composition: Denser, specialty cores typically offer better sound control.

  • Surface material: Wood, HPDL, or metal can reflect or absorb sound differently.

  • Perimeter seals: Gasketing around the door and frame is critical to prevent leaks.

  • Frame design: Double rabbets and filled frames can improve overall performance.

It’s not just about the door itself — it’s about how the entire door assembly is tested and installed. For STC ratings to hold true, all components must match the tested configuration.

Specifying with Confidence

To ensure the right performance:

  • Look for doors tested to the latest ASTM standards.

  • Clarify whether the rating is “sealed in place” (ideal conditions) or “operable” (real-world use).

  • Avoid substituting glass or hardware not tested with the original assembly, as this can invalidate the rating.

  • Work with experienced acoustical consultants for projects with strict acoustic requirements or post-installation testing needs.

Closing Thoughts

Acoustic-rated doors are only as effective as the assemblies they’re part of — and only as accurate as the way they’re specified. With dozens of core types, frame options, and hardware combinations available, it’s essential to rely on tested configurations, manufacturer guidance, and acoustic experts. A few smart decisions upfront can go a long way in delivering quieter, more comfortable spaces that live up to performance expectations.