Chosen primarily for its appearance and sound-insulating properties, acoustical plaster was used for houses and commercial properties. It was sprayed on interior ceiling and walls to enhance their appearance. The style of this textured look was popular for many years. The “popcorn ceiling” is an example of acoustic plaster that was used extensively throughout the United States.
However, the plaster’s appealing appearance was not the material’s only benefit. It also served the practical purpose of sound absorption. This meant that sounds in a room with a ceiling coated with this plaster were softer because of the reduction in echoing. The sonic insulating properties of acoustical plaster were especially popular with apartment buildings, where the plaster was used to dampen the noise between dwellings. It was also used in office buildings to soften sounds in smaller offices and because it provided an attractive look.
Asbestos in Acoustical Plaster
Unfortunately, throughout the 1950s companies added asbestos added to their acoustical plaster products. Asbestos was a popular mineral ingredient in many different products because of its unique ability to make sturdy materials that were extremely resistant to fire and heat. In spite of its practical applications, asbestos is toxic and responsible for causing many different diseases. Unfortunately, this connection was not widely known until the late 1970s. By that time, asbestos-laced acoustical plaster had been used in the construction of thousands of sites.
Although the plaster is a risk to health only when it is broken or disturbed, remaining relatively safe when intact, as buildings age and settle, this acoustical plaster is more likely to break due to stress and aging. This triggers the release of asbestos particles into the air. As buildings containing with this plaster age, the possibility of asbestos exposure increases. In fact, an early 1990s case addressed the threat of aging acoustical plaster in the case, Hebron Public School District No. 13 of Morton County, State of North Dakota v. U.S. Gypsum.
In that case, the Hebron School District brought this trial against the company, U.S. Gypsum, after acoustical ceiling plaster they installed in 1959 and 1963. This particular product was known as Audicote and a 1986 test of the school building ceiling revealed it contained asbestos material. U.S. Gypsum no longer manufactures this form of asbestos-tainted ceiling plaster, though it is important for individuals living in homes containing Audicote acoustical plaster from this era to have the dangerous material removed and seek medical attention for possible exposure.