| Layers | Typical lab STC | Relative cost |
|---|---|---|
| 2×4 studs, insulated, RC one side with 2 × 5/8 in, 5/8 in on the other | 55 | $$$ |
A strong upgrade for bedrooms and theaters. Loud music is barely audible and speech is inaudible.
Getting the rated performance
- Build it exactly as tested; small changes (screw spacing, stud gauge) change results.
- Seal the perimeter and all penetrations with acoustic sealant.
- Carry the wall to the structure above.
Values are typical lab ratings from published test data for similar assemblies; your manufacturer's tested assembly is the authority. Field performance is usually lower: see field ratings.