Concrete walls provide a buffer between: | Homeowners enjoy the quietness of a concrete home. PCA No. 15434 |
The greater mass of concrete walls can reduce sound penetrating through a wall by over 80% compared with wood or steel frame construction. Although some sound will penetrate the windows, a concrete building can be two-thirds quieter than a wood or steel frame building. Concrete panels also provide effective sound barriers separating buildings from highways or industrial areas from residential areas. Compared to a typical wood frame wall, only about one-quarter to one-eighth as much sound penetrates a concrete wall. Acoustics experts would describe loud speech on the opposite side of a frame wall as "audible, but not intelligible." On the opposite side of a concrete wall, a listener would "strain to hear" loud speech. Through some concrete walls, loud speech would be "inaudible." A 2 x 4 wood stud partition wall with ½ in. gypsum wallboard on each side has an STC (Sound Transmission Class) of about 35. With the addition of furring, insulation, and wallboard, STC values up to 63 are obtained for 6 and 8 in. thick concrete walls. Bare concrete and masonry walls have STCs in the range of 45 to 50. Standard flat panel ICF walls generally have STCs in the range of 55 to 60. A subjective description of STC values is presented in the table. STC -Lab | STC - Field | Subjective description of effectiveness | 26-30 | 20-22 | Most sentences clearly understood | 30-35 | 25-27 | Many phrases and some sentences understood without straining to hear | 35-40 | 30-32 | Individual words and occasional phrases clearly heard and understood | 42-45 | 35-37 | Medium loud speech clearly audible, occasional words understood | 47-50 | 40-42 | Loud speech audible, music easily heard | 52-55 | 45-47 | Loud speech audible by straining to hear; music normally can be heard and may be disturbing | 57-60 | 50-52 | Loud speech essentially inaudible; music can be heard faintly but bass notes disturbing | 62-65 | 55 | Music heard faintly, bass notes "thump"; power woodworking equipment clearly audible | 70 | 60 | Music still heard very faintly if played loud. | 75+ | 65+ | Effectively blocks most air-borne noise sources | |
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