This strong, durable board can be used in many applications where sound deadening is desired. Recommended for interior applications, this board is ideal for cutting sound transmission between interior rooms, between floors, or isolation from outdoor sound.

Introduction The aim of sound conditioning is reduction of distracting or irritating noise rather than "sound proofing" to totally eliminate sound Both the building materials and necessary techniques for increased privacy are available now to the builder who wishes to offer this significant tenant benefit to noise pollution conscious buyers. Economically preventing noise transmission through an interior wall was not an easy problem to solve. Thick walls of dense materials can stop sound; but, at a high cost and with structural problems created by unusually heavy walls. What is . . . Sound Deadening Board? Sound Deadening Board is a specially made structural fiberboard product designed for use in wall systems where sound control between rooms is desired. It is usually identified with the words "SOUND DEADENING BOARD" on each sheet or package to distinguish it from other fiberboard products. Take the "PARTY" Out of Walls Lightweight panels of Sound Deadening Board are specially made to trap noise passing through walls from room-to-room. The 1/2"-thick 4'x8' product works on the principle of combining dissimilar materials so that each does a different acoustical job. Sound Deadening Board is designed for use under gypsum wallboard. The heavy wallboard provides mass which retards the passage of sound, while the lightweight Sound Deadening Board panels act acoustically as an absorptive material which traps noise. Tests at a nationally known acoustical laboratory have shown that when Sound Deadening Board is combined with gypsum wallboard, the resulting wall is acoustically appreciably superior to walls made with:   • Two layers of Sound Deadening Insulation Board alone • Two layers of gypsum wallboard alone Sound Transmisison Class STC Sound Transmission Class (STC) is widely used as a performance criteria. STC provides a single number combining the wide range of frequency data points. Many of the new types of lightweight walls have low values in the middle frequency range as compared to the old solid masonry walls. How do conventional walls using 2"x4" stud framing rate by STC? Based upon tests, a typical based wall of gypsum wallboard, using 2"x3" or 2"x4" studs will have an STC of only 38. However, sound deadening board combined with Gypsum Wallboard will have an STC of 49!   STC numbers have been adopted by acoustical engineers as a measure of the resistance of a building element such as a wall to the passage of sound. The higher the number, the better the sound barrier. The following examples show the approximate effectiveness of walls with varying STC numbers. 30 35 42 45 48 50 Loud speech can be understood fairly well Loud speech is audible but not intelligible Loud speech is audible as a murmur Some loud speech - barely audible Must strain to hear loud speech Loud speech not audible Details Variations can be adapted from these basic wall systems:

On-Site Practices
It should be understood that the STC values obtained in actual practice will depend on many other construction factors besides the design of the partition itself. Attention must be paid to workmanship and construction details, and to the acoustical characteristics of the adjacent floor, wall, and ceiling structures which can provide "flanking paths" for sound transmission around a given partition. To be most effective, the perimeters of the walls must be sealed to avoid sound leaks.