Construction Suggestions for Noise Control
Homasote®
building products have been used successfully for decades to help deaden
sound in all types of residential and commercial construction. Combined
with - or added to - conventional partition and floor systems, 440 SoundBarrier®
will reduce transmission of airborne and impact sounds.
The cellulose fiber structure of 440 SoundBarrier lends itself to the
reduction of airborne sound levels (STC rating) by acting as a vibration
isolator. Homasote's unique manufacturing process randomly distributes
the cellulose fibers in a homogeneous mass which creates a building board
with a strong yet discontinuous construction. This internal structure,
combined with limited mechanical fasteners, helps break the path of sound
vibration.
In addition to breaking the path of airborne noise, the natural resiliency
of Homasote reduces and isolates impact noise. This is reflected in high
IIC ratings. Used as an underlayment, Homasote separates the finish floor
from the base structure, creating a sound barrier.
The following construction procedures should be followed so that the
laboratory results obtained by Homasote products can be translated into
satisfactory field performance:
- To eliminate noise paths around fixtures, outlets or ducts,
pack with acoustical batting material and caulk completely.
- Caulk at floor, wall and ceiling peripheries or wherever
walls meet floors and ceilings, to eliminate noise leaks. Apply a continuous
sealant over top plates and under bottom plates or track.
- Avoid back-to-back locations for outlets; stagger electrical
or antenna outlets so that each is isolated within two studs of the
partition. Seal openings around ceiling fixtures air-tight.
Impact Insulation Class (IIC)
Single-number rating that
indicates the amount of impact noise isolation provided by a floor/ceiling
assembly. The higher the number, the better the floor/ceiling assembly.
Sound Transmission Class (STC)
A single-number rating
that indicates the sound transmission loss of a partition or ceiling system
between adjacent closed rooms. STC Ratings are:
25 Normal speech can be understood quite clearly
30 Loud speech can be understood fairly well
35 Loud speech is audible but not intelligible
42 Loud speech is audible as a murmur
45 Must strain to hear loud speech
48 Some loud speech is barely audible
50 Loud speech is not audible
Homasote sound test results are stated in STC and IIC ratings.