How to Soundproof a Floor
While it is certainly possible to soundproof a floor in an older home, as with any soundproofing project it is easier to soundproof the flooring of a new home under construction. It’s simply easier to add the materials to the construction process than it is to rip up the flooring and start again later on.
Soundproofing a floor does present a relatively unique challenge. First, as with most sound blocking projects, you have to focus on the sounds traveling through the ceiling in the air. The second problem, unique to flooring, is the sound of impact noise. Impact noise is caused by footsteps, dragging furniture, or other sounds caused by the impact of an object hitting the floor. Impact noise is particularly unique because it can not only create noise but can also create vibrations (for example, in the case of a heavy footstep).
We’ve worked hard to design a solution to the problems created by floor/ceiling systems. While some of the others on the market seem a bit complex, you’ll find that the following steps will allow you to create a feasible sound barrier within a relatively short period of time.
While the joist system in the floor/ceiling is still open you’ll want to apply some gasket tape to the joists. Gasket tape will help to prevent squeaks from developing in the future. They usually develop over time as the joists in the subflooring become loose and start to rub against each other when there is movement above. The gasket tape prevents the squeaking sound from occuring even if the joists do become loose.
Install your subflooring over top of the joists. Once it is down you’re going to apply a layer of Green Glue over top of the subflooring. Make sure you use a full two tubes for every 4×8 sheet of subflooring you use. Install a layer of soundboard over top of the subflooring, apply a second layer of Green Glue, and install a second layer of subflooring (usually plywood).
Now, that last part may seem like a lot of extra work. If you are on a budget, however, you can simplify your soundproofing project by eliminating the first layer of Green Glue and the soundboard, instead installing just one layer of Green Glue between two layers of subflooring.
Grab your favorite acoustical caulk, line the perimeter of the room, and make sure the soundproofing work you did is properly sealed. Install your flooring over the subfloor. If you’re installing carpet, make sure you use a very thick carpet pad.
The rest of the project will happen from below, as you work on the ceiling beneath the floor you just worked on. Make sure you read up on how to soundproof a ceiling before you get started. Between the two, you’ll never have sound problems in either room!