SSOT v3.7 · Project Reference · Acoustic Design Basis

Green Glue Application Guide

Field guide for applying constrained-layer damping compound between gypsum boards. The target performance uplift is typically +5 to +8 dB STC in the mid-frequency range when the product is applied and cured correctly [AC].

Coverage
2 tubes / sheet
Edge Margin
25 mm clear
Open Time
15 minutes max
Cure
30 days [AC]

What Green Glue Does

Damping Mechanism

Without Green Glue

Vibration transfers directly from one board to the next, allowing more energy to pass through the leaf.

Gypsum layer 1 Gypsum layer 2 More direct transmission

With Green Glue

The viscoelastic compound shears between the boards and converts vibration into heat, increasing damping.

Gypsum layer 1 Green Glue Gypsum layer 2 Vibration converts to heat Typical uplift: +5 to +8 dB STC

Application Pattern

1220 × 2440 mm Sheet

Apply approximately 20–25 blobs over the back face of the second gypsum sheet. Do not trowel or spread. Keep all compound at least 25 mm away from panel edges.

1220 mm gypsum sheet width 2440 mm gypsum sheet height Blob size 40 mm dia 5 mm thick Tube count 2 tubes per sheet Edge rule Keep 25 mm clear Do not spread 25 mm edge no-go zone

Step by Step

Execution Sequence

  1. Step 1

    Fix the first gypsum layer to the studs or resilient channel in the approved pattern.

  2. Step 2

    Apply Green Glue blobs to the face of the second sheet. Do not place compound on framing members or sheet edges.

  3. Step 3

    Press the second sheet against the first within 15 minutes of application.

  4. Step 4

    Screw the second sheet back to the framing. The compound should shear between the boards as it is compressed.

  5. Step 5

    Allow 30 days cure before formal acoustic testing [AC].

Which Walls Get Green Glue

W3 / W4 / W5 / W7
WallGreen Glue?PlacementReason
W3Yes [AC]Both sidesServer wall needs added damping to reach STC 62.
W4Yes [AC]Both sidesRebuilt south wall relies on constrained-layer damping.
W5Yes [AC]Both sidesBuffer spine requires added control at speech frequencies.
W6NoStaggered stud designIsolation is achieved primarily by decoupling rather than damping compound.
W7Yes [AC]Studio side onlyTarget uplift from STC 40 to STC 48 depends on the upgraded studio-side layer.
WrongRight
Spreading like paintLeave as blobs
Applying to edgesKeep 25 mm margin
Waiting more than 15 minutesLaminate immediately
Using 1 tube per sheetUse 2 tubes per sheet
Testing at 7 daysWait 30 days for full cure