4th-yr-Abcm-How To Build A "Room-Within-A-Room" (sound proof room)

Get the ultimate in sound-proofing by borrowing this idea used in professional recording studios.

One of the most effective ways to control the leakage of sound is to build a room within a room. Forcing the sound waves to have to travel through a double-wall, or a double-floor weakens it considerably. This also has the double effect of isolating the movie-goers within the room from sounds coming in from the outside.

Lets say you have an existing room in your basement thats already framed and drywalled. To build your room within a room, you'd have to construct four new walls, a new ceiling, and a new floor. There has to be absolutely no contact between the inner and outside walls and ceiling. The whole thing would then have to "float" above the existing cement floor on special rubber footings.

You would start by building a floor using similar techniques used to frame a wall. To reduce the amount of wasted space, the width and length of the new floor should be about 6 inches less than the width and length of the room it will be in. This will provide enough of a gap between the rooms to reduce the transmission of sound.

Instead of using drywall, you would use 3/4" plywood on the bottom of the new floor. You'd then fill the gaps between the studs with fiberglass insulation. You can also use special insulation products such as Owens Corning QuietZone and Roxul's Safe'n Sound which provide both fire resistance and sound deadening. Be sure to use a breathing mask and gloves when handling any fiberglass insulation product. Before finishing the floor with 3/4" plywood, mark off the location of each stud. These marks will help you easily find the studs later when you have to screw the walls to them.

Build the new floor on 1/4" to 1/2" thick rubber isolation mats. These mats are designed to virtually eliminate the transmission of sound vibrations. They're usually a specialty item but can easily be purchased online.

Now that our room within a room has its new floor, its time to build the walls. You will frame each wall and hang drywall on the side that will be facing the gap. Raise each wall into position and screw them into the floor's studs using the markings you made earlier.

Regular ceilings in a house are built using ceiling joists. These are wooden members that span the width of a room and hold up the ceiling, roof, or floor of a house. In our case, we can get away with using 2x4's for our ceiling joists since we don't need to hold up anything other than the ceiling's drywall and some light fixtures. Its pretty hard to frame a completed ceiling and lift it into place so you'll have to build it piece by piece.

A wall has both a top plate and a bottom plate. Ceilings on the other hand have header joists to which the 2x4's are connected. Install a pair of header joists on two walls that oppose each other. Starting at one end of the room, screw a series of 2x4's between the header joists 16 inches on center.

When each wall and ceiling are framed and installed, its time to lay out your electrical wiring. Though this site is for the do-it-yourselfer, I recommend you hire a professional electrician for this part of the project. With the electrical wiring completed and inspected, its time to install more sound insulating fiberglass insulation between the wall studs and in the ceiling.

You'll then finish the job by filling in the empty space between the exposed studs in the walls and ceiling with more fiberglass insulation. When done, you'd hang the rest of the drywall on the inside walls of your new room. You can rent a panel lift or use a T-brace to help lift the drywall to the ceiling. You can use a solid wood or steel door and you can install weather stripping to seal off any cracks.

With all this talk about insulation, you'd be right if you started to think our new room would get pretty warm. I didn't talk about ventilation just yet. I'll reserve that for another blog.