Multi-layer acoustical building panels

An acoustic ceiling panel having a first major exposed surface opposite a second major exposed surface, the acoustic ceiling panel comprising:

• a first layer having an upper surface and a lower surface, the lower surface forming the first major exposed surface of the acoustic ceiling panel, the first layer comprising:
• a first body comprising a fibrous material and having a first major surface, a second major surface, and a side surface extending between the first and second major surfaces;
• and
• a first attenuation coating at least partially covering the side surface of the first body;
• a second layer having an upper surface opposite a lower surface, the upper surface forming the second major exposed surface of the acoustic ceiling panel, the second layer comprising:
• a second body comprising a fibrous material and having a first major surface, a second major surface, and a side surface extending between the first and second major surfaces, the second major surface of the second body facing the second major surface of the first body;
• and
• a second attenuation coating applied to at least a portion of the second body;
• wherein at least one of the first and second attenuation coatings is located between the second major surface of the first body and the second major surface of the second body;
• and
• wherein at least one of the first major surface of the first body and the first major surface of the second body is free from the first attenuation coating and the second attenuation coating.

A method of forming an acoustic ceiling panel, the method comprising:

• a) forming a first layer of the acoustic ceiling panel by at least partially coating a first air-permeable body comprising a fibrous material with a first attenuation coating;
• b) forming a second layer of the acoustic ceiling panel by at least partially coating a second air-permeable body comprising a fibrous material with a second attenuation coating;
• c) applying an adhesive to at least one of the first layer and second layer;
• and
• d) joining the first layer and the second layer together, whereby the adhesive is located between the first layer and the second layer;
• wherein the first air-permeable body comprises a first major surface, a second major surface, and a side surface extending between the first and second major surfaces;
• wherein the first attenuation coating at least partially covers the side surface of the first air-permeable body;
• wherein the second air-permeable body comprises a first major surface, a second major surface, and a side surface extending between the first and second major surfaces;
• wherein at least one of the first and second attenuation coatings is located between the second major surface of the first air-permeable body and the second major surface of the second air-permeable body;
• and
• wherein at least one of the first major surface of the first body and the first major surface of the second body is free from the first attenuation coating and the second attenuation coating.