Sound Insulation Calculator

STC improvement from insulation type in wall assembly.

Inputs

Wall assembly

Insulation type

Resilient channel

Green Glue compound

Add extra drywall layer

Wall area

sq ft

Tab to move between fields

Results

Final STC rating

Perceived noise reduction

38%

Base STC (before treatments)33

STC improvement7 points

Material cost$132.00

RatingFair — loud speech heard as murmur

How to Use This Calculator

Enter Wall assembly, Single 2×4, drywall each side (STC 33), and Single 2×6, drywall each side (STC 37).
Set Single 2×4, double drywall one side (STC 38), Staggered stud 2×4 (STC 46), and Double 2×4 wall with gap (STC 50).
Adjust Insulation type, None as needed.
Review Final STC rating and Perceived noise reduction (%).
Use Base STC (before treatments) and STC improvement (points) to inform your decision.

What each input means

Wall assembly: Base wall framing and sheathing type.
Insulation type: Cavity insulation. Mineral wool is best for sound; closed-cell foam is worst.
Resilient channel: Metal channels that decouple drywall from studs (+6 STC). Very effective.
Green Glue compound: Viscoelastic damping compound between drywall layers (+4 STC).
Add extra drywall layer: Second layer of drywall adds mass (+5 STC). Best with Green Glue.
Wall area: Total wall area to soundproof.

What each result means

Base STC (before treatments): Starting STC rating of the wall assembly alone.
Final STC rating: Achieved STC after all treatments. STC 50+ is recommended between units.
STC improvement: Total STC points gained from treatments.
Perceived noise reduction: Approximate perceived loudness reduction. Every 10 STC sounds half as loud.
Material cost: Estimated material cost for selected treatments.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Wall assembly = 0, Insulation type = 2, Resilient channel = 0, Green Glue compound = 0 = 6 input(s) provided
Calculate Final STC rating
Final STC rating
40 = 40
Calculate Perceived noise reduction
Perceived noise reduction
38 = 38
Calculate Base STC
Base STC
33 = 33
Calculate STC improvement
STC improvement
7 = 7

Engine last updated July 28, 2026.

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