Hard Surfaces — Acoustic Material Guide
Hard surfaces including bare concrete, plasterboard, exposed brick, metal deck soffits, ceramic tile, and painted concrete block are highly reflective with NRC values of 0.05-0.10. Understanding their acoustic contribution is essential for calculating existing room conditions before specifying treatment. Rooms dominated by hard surfaces typically have RT60 values 2-5x above recommended limits.
Products in This Category
| Material | NRC | αw | Applications |
|---|---|---|---|
| Bare Concrete | 0.05 | 0.05 | Floor, Ceiling, Wall |
| Plasterboard (Gypsum Board) | 0.10 | 0.10 | Wall, Ceiling |
| Exposed Metal Deck Soffit | 0.05 | 0.05 | Ceiling (structural) |
| Exposed Brick | 0.05 | 0.05 | Wall |
| Ceramic Floor/Wall Tile | 0.05 | 0.05 | Floor, Wall |
| Painted Concrete Block | 0.05 | 0.05 | Wall |
Average Absorption Profile
Average absorption coefficients across all hard surfaces materials at each octave band frequency.
| Frequency (Hz) | 125 | 250 | 500 | 1000 | 2000 | 4000 |
|---|---|---|---|---|---|---|
| Avg α | 0.06 | 0.04 | 0.04 | 0.03 | 0.04 | 0.05 |
Best Applications
Room types and environments that benefit most from hard surfaces materials:
Related Standards
International and national standards relevant to hard surfaces selection, testing, and specification:
Installation Notes
Hard surfaces are the baseline condition in untreated rooms. When modelling existing spaces, accurately identifying and measuring all hard surfaces is critical for calculating the required absorption area. Plasterboard on resilient channels provides some low-frequency panel absorption.
Typical thickness: Varies (structural)
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