Acoustical Advantages of Precast Concrete

Acoustical Advantages of Precast Concrete

The purpose of architectural acoustics is to create an environment where sounds are clearly heard by the intended listener and noise is isolated or absorbed. These are two ways of dealing with sound levels: sound insulation and sound absorption. Materials with a heavy mass (like concrete walls) work well with sound insulation, while porous lightweight materials work well with absorption. Sound insulation is usually more complicated than absorption.

STC (Sound Transmission Class) is a numerical rating system on how well a building partition reduces the amount of noise at a given frequency that passes through. The higher the STC, the better the performance of sound insulation.

STC     What can be heard

25       Normal speech can be understood quite easily and distinctly through wall

35       Loud speech audible but not intelligible

40       Onset of “privacy”

45       Loud speech not audible; 90% of statistical population not annoyed

50       Very loud sounds such as musical instruments or a stereo can be faintly heard; 99% of population not annoyed

60+     Superior soundproofing; most sounds inaudible

An STC rating of 50 will satisfy most building code requirements. An 8” CarbonCast

panel with 4” of insulation will provide a STC rating of 52. This rating can be

increased if required by adding more mass to the wall.

The STC rating of a wall can be severely compromised through leaks and flanking. This may occur wherever there are penetrations, openings, windows, doors and gaps. Special attention needs to be paid during the design process to limit and correct these concerns. Because CarbonCast walls are produced in large widths and full height modules with caulking and insulation at the joints, there is much lower probability of leaks of flanking as compared to steel or wood structures.



3 thoughts on “Acoustical Advantages of Precast Concrete

  1. Tomas Killington

    I had no idea how great of a sound barrier precast concrete was. When I’m in industrial buildings I can definitely tell when they’re poorly insulated for sound. Concrete definitely seems to be a good option if sound is an issue.

  2. John

    I thought it was really interesting to see the STC rating listed in the article. It was also interesting how it mentioned that most building codes require a rating of 50. I had no idea that architectural acoustics was so important!

  3. Kylie Dotts

    I didn’t know that precast concrete could work well with sound insulation for a room. There are some building that I have been in that are almost completely sound proof and I wonder if they have used this kind of material to make it so quiet. I wonder if my husband could make a shed out of the same stuff so we wouldn’t have to hear his power tools all day and night while he’s out working on a project.


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