Acoustical ceilings are used by interior designers seeking an affordable way to lower the height of a modern room and also deaden ambient noise. Typically, a grid work of metal strips is hung from the room's true ceiling and individual panels of sound-absorbing material are dropped into the sections. Heating and cooling ducts can be hidden behind acoustical ceilings, along with wires for overhead lighting and pipes for plumbing fixtures.
The use of acoustic ceilings reached its zenith in the 1960s through the early 1980s. In 1978, products containing asbestos were banned for home use by government regulators, and this affected the manufacture and installation of most acoustic ceiling panels in use at the time. Many homeowners hired specially-trained contractors to remove the older acoustic ceilings from their homes. Some restored the ceilings to their original dimensions, while others selected new acoustic ceiling panels which did not contain asbestos. The typical “popcorn”-textured acoustic ceilings also fell out of favor with the advent of more stylized paneling.
Acoustic ceilings do help to dampen noises between floors and they can be painted to match the decor of the room. One drawback with traditional acoustic ceilings is the appearance of water stains from roof leaks. The pooling water can create a buckled appearance or cause an individual panel to fall out unexpectedly. Dried water stains can be very unsightly, but treatment with bleach or a special acoustic panel restorative can help. Replacing an individual panel in an acoustic ceiling is not especially difficult, so homeowners can change from finish to finish with relative ease.
All ceilings are acoustical to some degree. Ceiling materials such as plaster, drywall, and metal decking, for example, still have some acoustical value, although it is very small. These materials have longer reverberation times, which could afford a desirable sound quality for a given space. Materials that are softer, such as mineral and wood fibers, fiberglass, cloth, and acoustic tiles, are more sound absorbing because they have shorter reverberation times. These materials would be desirable for work areas, classrooms, and conference rooms where a speaker needs to be heard.
Sound is energy in the form of vibrations, and it varies in intensity and frequency. Sound energy can be reflected, absorbed, or transmitted, depending on the material it is coming into contact with; surfaces other than ceilings in a room have a significant effect upon its acoustical properties. The more porous the material, the more easily the sound energy is absorbed, therefore fiberglass, for example, is a good absorber, whereas concrete is not. Sound that is not absorbed or transmitted through will be reflected back. This can be a desirable quality, as it is, for example, in music rooms.
Acoustical ceiling materials have various ratings which one should take into consideration.
- NRC – Noise reduction coefficient, having to do with the sound absorption of the material. Used as a measure for smaller spaces such as offices or classrooms.
- AC— Ceiling articulation class, a measure for sound absorption in open space or large areas like auditoriums or multi-purpose areas.
- CAC – Ceiling attenuation class, refering to the ability of the ceiling material to block sound.
- STC – Sound transmission class,which measures the blocking of transmission through the material.
No one ceiling tile material is the solution to all projects. Once a project’s needs have been determined, a variety of acoustic ceiling tiles can be considered.
With today’s construction professionals seeking ways to reduce environmental footprints, many manufacturers of acoustical ceilings reclaim and recycle old ceiling material from renovation projects. Be sure to investigate what “green options” you have before selecting a type of acoustic ceiling.