Pre-Engineered Drywall
As we outline in our course on Sound Transmission, structure borne vibrations are the true medium through which sound waves will pass through a common surface. By adding density to the surface, and disconnecting the assembly, you are able to impede the wall's ability to vibrate, and can force the collapse of the transmitting sound wave. This process can trigger a dramatic drop in sound bleeding through common walls or ceilings, triggering luxury grade STC ratings.
So how do we disconnect the wall? And how do we add density?
In the old days, lining the walls with heavy lead sheeting was a common practice, layering it behind drywall. But for health reasons, lead sheets were replaced with a safer material to handle called mass loaded vinyl. These are thin rubber rolls that layer mechanically to a sub-surface prior to hanging normal drywall. The density of this material impedes the surfaces ability to conduct vibrations, and is a safer alternative to lead. NetWell calls this material dB-Bloc. Through proper wall or ceiling assembly, this material can combine to trigger a drop in sound transmission by up to 90%.
A few years ago, the market was then introduced to pre-engineered drywall. Pre-engineered drywall is actually a double layer of drywall with a constrained membrane sandwiched between the two sheets. The weight and damping ability of this material also serves to deaden the transmission of sound through a wall. Does it work? Yes. So long as you are willing to commit to the following:
a. Still disconnect your framing;
b. Spend $120 per sheet for pre-engineered drywall
c. Pay sales tax to a local dealer
Remember, a standard sheet of 5/8" drywall at your local building supply house will cost $5-10. By lining your surface with the density of dB-Bloc and disconnecting your framing, you can trigger the same drop in transmitting sound waves by using standard drywall. Do the math. Figure how many 4'x8' sheets of drywall are needed for your treatment, and see if saving $100 per sheet is worth it to you. For the bulk of our clients, the answer is of course obvious. Often times, what you end up paying your local dealer in sales tax alone for pre-engineered drywall can cover the cost of standard 5/8" drywall.
Also, take a look at the scrap pile of drywall in the middle of your floor upon completion. Would you have rather paid $5-10 per sheet for that rubble, or $120 per sheet? The waste is expensive, the shipping is expensive, the installation is more difficult, and equal results can be triggered using dB-Bloc and a disconnecting framing technique. And unless you live in Minnesota, we ship dB-Bloc tax free.
Show me dB-Bloc