Skip to main content
Version: 2026.08.01

Sound Insulation

Sound insulation refers to a floor or wall system's ability to reduce airborne noise entering a room from rooms above, below, and adjacent, as well as noise from movement such as walking overhead. Classic's sound insulation option mitigates noise; it should not be confused with soundproofing, which is not available through Classic.

When deciding on sound insulation for a wall (R-13) or floor (R-17), consider both airborne and impact noise insulation as well as how the system integrates with other building elements.

Airborne and Impact Noise​

There are two types of noise to consider when choosing sound insulation and flooring:

  • Airborne noise is radiated directly from a source—such as a loudspeaker, stereo, television, people talking, or a dog barking.
  • Impact noise is produced by the collision of two solid objects—such as footsteps or dropped objects on a floor, wall, or ceiling.

Reducing noise transfer through I-joist floors and between walls involves many factors:

  • Floor surface type (carpet, tile, wood, etc.)
  • Insulation between the floor and ceiling and within defined walls
  • Whether a basement is unfinished or finished (a finished basement adds a drywall ceiling)
  • Furniture type and placement
  • Window coverings

Floor Finish​

For floor and ceiling systems, the main concern is impact sound transferring to the room below. In I-joist constructed systems, the surface finish is the most significant factor in impact sound. Hard surfaces such as hardwood, stone, and ceramic tile are more problematic than soft finishes such as carpet, because they can increase structure-borne sound transfer. Carpet is one option to consider for improving impact sound insulation.

Alternative hard-floor systems can also be considered with appropriate acoustic treatments, such as a foam underlayment under hardwood. The choice of floor covering is an important part of both the initial finish and any future upgrade.

Reflected noise within a room is a further consideration. Smooth surfaces tend to reflect high-frequency noise, while surfaces such as carpet absorb sound better than hardwood and tile. A high reverberation time can lower speech intelligibility and raise internal noise levels, which in turn increases noise transfer to adjacent rooms. Selecting absorbent floor coverings such as carpet, or absorbent furnishings such as rugs or heavy drapes, helps reduce reverberation.

Related: See Noise Issues in the Warranty guide for how noise concerns are evaluated after closing.