The partition walls in most family homes are constructed of drywall (wallboard) firmly attached to both sides of a wood or metal stud frame. When sound waves hit one side of the wall it causes the drywall on that side to vibrate. Since the drywall is rigidly connected to the stud frame, the vibration is transmitted right through the studwork to the drywall on the other side. Those same vibrations traveling through the studwork can also channel noise throughout adjacent floors and ceilings. Noise will radiate easily through the structure because there's almost nothing there to cushion and absorb the sound waves.
At the introduction to this series we discussed some rather inexpensive solutions for sound control that produce fair to good results, the following solutions are a little more costly but more effective.
Improving on an Existing Wall:
This is a basic system.
Laminate the existing wall with Soundboard, a material made from compressed wood fibers and recycled paper. Construction adhesive makes this a quick operation. You can get it at most commercial drywall suppliers
Next install a new 2" metal framed wall 1/2" or more away from the existing wall. 2" metal studs are very easy to work with and keep the wall thickness at a minimum. Pack the wall cavity with fiberglass insulation, since we are not that concerned with the "R" value as much as sound deadening. Hang new drywall, tape, finish and paint with Acousti-Coat
More Effective...
A well-constructed and sealed staggered-stud wall design has a very high STC of 60. This design uses an extra wide base plate. For example you use a 2" x 6" base plate and alternately position the studs to the outer edges of the plate, 1 to the inside, next one to the opposite edge etc. No stud actually touches both walls so there is no direct sound path. You can improve on this design by using separate base plates under each set of studs. The insulation is snaked through the stud-to-wall gaps along the entire length. This leaves no voids to let noise through. ( Basically you are building two separate walls.)
System #1
5/8" type "X" fire rated drywall has much better sound deadening properties than 1/2" reg drywall. The cost is not that much more so I recommend you use 5/8"X. Attach it to the studs using construction adhesive and a few screws to hold it in place until the adhesive dries. Avoid using too many screws...this is a path for sound to travel, 6-8 per 4'x8' panel of drywall is enough to hold it.
When installing the drywall do not fit it tight into the ceiling, corners or floor. Hold it off at least 1/4" and use an acrylic caulking to fill those gaps. The caulking acts as a flexible buffer for sound vibration so that it minimizes the sound transfer.
Caulk an fill ALL openings, around outlet and switch boxes, light fixtures etc. NO Cracks or holes left uncaulked!
Tape and finish the drywall using normal procedures->Finishing Drywall
Want More Soundproofing?
System #2 is Really Serious!
