Understanding acoustical assemblies with The SoundBook

Sep 12, 2022

With detailed acoustical assemblies, The SoundBook provides insights to help architects and contractors design and build with confidence


While structural integrity is the most important project design consideration, acoustics also play a role in designing a building for optimal occupant comfort. To make planning for noise easier, National Gypsum Company created The SoundBook®, the industry’s leading resource for technical details and sound-rated assembly drawings.

In addition to providing high-value products manufactured by its affiliate companies Gold Bond Building Products, PermaBASE Building Products and ProForm Finishing Products, National Gypsum offers a wide variety of technical resources. Let’s take a quick walk through acoustical code requirements, common challenges with acoustical assemblies and how The SoundBook can provide solutions.

What are the key acoustical requirements in the building code?

The International Building Code (IBC) provides a model on which local building codes are based. The IBC has two main acoustical requirements:

  • IBC 1206.2 (2018): States that airborne sound must be controlled by assemblies meeting a minimum lab-tested Sound Transmission Class (STC) rating of 50 per ASTM E90, or 45 if field-tested. This code section applies to walls, partitions and floor-ceiling assemblies separating dwelling and sleeping units from each other or from public service areas.
  • IBC 1206.3 (2018): Is identical to IBC 1206.2, except it references structure-borne sound and must meet a minimum lab-tested Impact Insulation Class (IIC) rating of 50 per ASTM E492, or 45 if field-tested.

Otherwise, most acoustical requirements come from building owners and architectural best practices.

Basic acoustical wall design concepts include:

  • A stiffer wall makes it easier for sound to pass through — walls that can vibrate make it harder for sound to pass.
  • Closer stud spacing leads to stiffer walls and more sound transmission.
  • More layers of gypsum board will decrease sound passing through an assembly.
  • A deeper stud cavity will result in decreased sound transmission.

Using these acoustical wall design concepts will help you provide spaces that enhance the occupant experience. You can also learn more about reducing sound transmission between floors by reviewing acoustical design considerations for floor-ceiling assemblies.

With these tenets in mind, architects, engineers, designers and contractors involved in the design process should always review assembly details with the governing code and inspection official at the time of the project submission to determine if there are any discrepancies.

What are the most common challenges in creating acoustical assemblies?

Based on customer inquiries to National Gypsum’s Construction Services team at 1-800-NATIONAL®, the biggest challenge in creating acoustical assemblies comes from balancing the need to meet the STC rating with design parameters that will reduce the rating. For example, it would be simple to achieve the desired STC rating with studs that are 24” on center with SoundBreak® XP® Fire-Shield® Gypsum Board on one side, but design constraints may require 16” on center stud spacing which isn’t as optimal for sound control. Finding a solution to meet the STC requirements can be a challenge, and that’s where The SoundBook comes in handy.

What is The SoundBook?

National Gypsum Company’s The SoundBook acoustical assembly guide is designed to help architects and contractors find solutions to challenges such as the one mentioned above.

The SoundBook is a collection of sound assemblies developed and tested by our experts in accordance with ASTM E90 under controlled laboratory conditions. Compared to other similar resources, it features more assemblies, presented in greater detail, with three-dimensional renderings. The assemblies in The SoundBook can be used in residential or commercial buildings.

In National Gypsum’s commitment to service and support, many of the assemblies found in The SoundBook are based on questions received by our 1-800-NATIONAL Construction Services team.

How is The SoundBook organized?

The SoundBook is broken down into sections that encourage ease of use and being able to locate the assembly you need when you need it:

  1. Acoustical Terms and Concepts
  2. Steel Stud Partitions with Framing 16" o.c.
  3. Steel Stud Partitions with Framing 24" o.c.
  4. Steel Stud Chase Walls
  5. Shaftwall Partitions
  6. Wood Stud Partitions with Framing 16" o.c.
  7. Wood Stud Partitions with Framing 24" o.c.
  8. Wood Stud Chase Walls
  9. Area Separation Fire Walls
  10. SoundBreak XP RetroFit Partitions
  11. Floor-Ceiling Assemblies
  12. Roof-Ceiling Assemblies
  13. Ceiling Attenuation Class Assemblies

Architects, contractors and code inspectors can use The SoundBook in the field to compare in-place construction against tested assemblies in the book. The SoundBook can also help verify that construction assemblies meet with industry best practices and code requirements.

For more information on acoustic assemblies, visit The SoundBook resource library.


Editor’s Note: We’ve recently updated this post to reflect changes in product names. For clarity, the revised names are as follows:

  • Gold Bond® SoundBreak® XP® Gypsum Board
  • Gold Bond® SoundBreak® XP® Fire-Shield® Gypsum Board
  • Gold Bond® SoundBreak® XP® Fire-Shield C™ Gypsum Board
  • Gold Bond® SoundBreak XP Retrofit® Gypsum Board

Contact 1-800-NATIONAL if you have additional questions.