Soundproofing your Basement

In today's world, basements are no longer simply places to store things like a glorified garage. With the price of housing ever on the rise, many people are converting their basements into rental spaces where they can make a little extra income each month. There are also a lot of folks who want to create a refuge space for reading or meditation or even a home theater in their basements. In this article I am going to talk about soundproofing your basement from the tenants below or from the noise transmitted by a home theater.

The first order of business is to talk about the ceiling. Many times pipes and conduits as well as electrical and cable lines run between the joist cavities in a basement ceiling. A lot of people feel that need to have access to these components, but in order to achieve great soundproofing, there devices need to be sealed up by constructing a sealed drywall ceiling below. If you are concerned about the plumbing and wiring, have a professional come in before your drywall in your new ceiling. Remember that 90% of your plumbing and wiring is behind drywall and if there are problems with them then naturally the drywall will need to be removed. My point here is that if the plumbing and wiring has been inspected and given a clean bill of health, then go ahead and seal up the ceiling below.

Generally most basement areas have low ceilings which prevents us from installing a fully floated ceiling, however there is always room for materials like mass loaded vinyl that can be stapled or nailed directly to the bottom of the joists like a membrane. You will caulk all of the seams as well as around the entire perimeter of the MLV using a good quality acoustical caulk, stay away from cheap silicone caulks, they do not work as well.
Once the MLV membrane is caulked and sealed properly, it is advised that you also tape the seams with a lead tape or a mass loaded vinyl sealer tape. You will tape directly over the dried caulk. Now it is time for a layer of drywall. I would recommend a layer of 5/8" fire code drywall. This application will stop most of the airborne sound transmission and some of the impact noise from above, but the best way to alleviate the majority of the footfall or impact noise is to float your ceiling using sound clips and metal furring channels. I will talk more bout them in subsequent articles.

There is one other method for soundproofing a basement ceiling that I will briefly discuss. Instead of using the mass loaded vinyl, consider installing 2 layers of sheetrock with a layer of Green Glue applied between the 2 layers. Here's how it works. First you make sure you have your batt insulation in place between the joist cavities, this is only necessary if your need the thermal protection of the insulation. Next you would screw in a layer of 5/8" drywall. Always screw in your drywall; never nail it in especially in a ceiling application. Then you will lay out your second layer of 5/8" drywall on saw horses, but on this layer you will apply 3 tubes of a product called Green Glue top the backside of the drywall. Green Glue is a visco elastic damping compound that is used to deaden or dampen the existing drywall and the newer layer that is being installed. You could apply only 2 tubes of Green Glue per 4' X 8' sheet of drywall, however using 3 tubes per sheet of drywall is much better for soundproofing. Once you have applied the Green Glue to the backside of the second layer of drywall, you will simply screw in the second layer directly over top of the first layer. A little hint here is to screw the second layer of drywall down as tightly as possible without pulling the screw through the drywall, this will insure the best dampening possible of both pieces of drywall.

After that second layer of drywall and Green Glue are installed, you will simply tape mud and texture the ceiling as you would a normal ceiling. Well, that's all there is to soundproofing a basement ceiling. For more information about soundproofing a ceiling, walls or floors, read my subsequent articles or simply call a reputable soundproofing company, they will be glad to help you. Until next time, this is Dr. Bob...Out!