Impact noise is structure-borne sound generated by an object striking a building assembly, such as footsteps on a floor. The most effective method to mitigate this type of noise is to isolate the impact at its source. A resilient underlayment, installed between the finished hard flooring and the subfloor, acts as a shock absorber. This decouples the flooring surface from the main structure, dissipating the impact energy before it can travel through the floor joists and radiate as sound into the space below. This method directly addresses the cause of the problem, making it superior to treatments that only manage airborne sound.

A. Higher NRC in the ceiling material addresses airborne sound absorption within a room (reverberation), not the transmission of structure-borne impact noise from the floor above.

B. A framed-in upholstered wall panel system is a treatment for walls and primarily controls airborne sound; it has no effect on impact noise from the floor/ceiling assembly.

D. Blanket insulation is effective at absorbing airborne sound within the floor/ceiling cavity but is significantly less effective at mitigating direct impact noise than a resilient layer at the source.

1. Ballast

David Kent. Interior Design Reference Manual

6th ed.

Professional Publications

Inc.

2012. Chapter 10: Acoustics

"Impact Noise

" pp. 10-8 to 10-9. (This section explains that impact noise is controlled by methods that cushion the impact

specifically mentioning carpet

padded underlayment

and resilient underlayments to improve the Impact Insulation Class (IIC) rating).

2. Ramsey

Charles George

and Harold Reeve Sleeper. Architectural Graphic Standards

12th ed.

edited by The American Institute of Architects

John Wiley & Sons

2016. Chapter 8: General Construction

"Acoustical Design

" Subsection "Control of Structure-Borne Sound

" p. 698. (This source illustrates that structure-borne sound is controlled by isolating and damping the vibrating source

for which resilient materials in a floor assembly are a primary method).

3. Quirt

J.D. Guide to Sound Insulation in Wood-Frame Construction. National Research Council Canada

Institute for Research in Construction

1985 (revised). IRC-IR-693. Section 3.2 "Impact Sound Insulation of Floors

" pp. 16-18. (This guide states

"The most effective way to improve the impact insulation of a floor is to use a soft floor finish... A resilient underlay under a hard floor finish can also be very effective.").