Part 2 : the Sound Proof Walls
This series of articles is more of a picture book of the floating room that we built for the live room of the studio here at Revolution Audio in Mississauga, Ontario, Canada. (Caution this may take a few moments to load all the pictures)
Now we come to adding the walls onto our floating floor. Notice the final layer of the floor (the manufactured hardwood) will be completed after the walls are finished and painted. For the walls, I was shooting for an STC rating of around 62 which would allow me to record drums in the room without disturbing the neighboring businesses. So I decided upon a double steel studded wall assembly with double drywall on the inside.
For the STC ratings of various wall assemblies, this is a great website and resource: www.STCRatings.com
Of course, there is no such thing as a true sound proof wall. The proper term is "sound isolation." So you need to decided from from the front end how isolated you want your room to be. The three keys to isolation are three "d's" : density, distance and decoupling. We add density through the double drywall layers (5/8 inch in this case) and the safe n' sound insulation. We add distance between the inside and outside walls creating at least a 9 inch air gap. (We would actually decrease the STC rating by adding drywall in the middle of this assembly). By using double steel studs and resilient channels we decouple the walls from one another so that the sound has a harder time vibrating through to the opposing room.
You will see through the pictorial below that we built the inside walls on top of the floating floor, giving one more step in isolation from the outside wall. The ceiling then was built upon the interior walls, basically creating a floating room.
Ewen is seen here constructing the frame for the interior walls and ceiling.
Notice how the frame is built on the floating floor.
The interior ceiling will rest on the top of the walls and have no solid connection to the ceiling above. This is key for decoupling. You will have to consider the weight of the ceiling material to make sure it will hold!
The slant on the ceiling frame is intentional...really!
We installed this temporary bar in to keep the whole room from leaning before we could get the drywall on.
Here is the finished frame with safe n' sound insulation and the resilient channels on the ceiling.
Jak installing more resilient channels. Every bit helps with soundproofing.
Jak mudding the first layer of drywall. Attention to detail is important.
Here you can see the second layer of drywall being placed on the ceiling. It is important to stagger the seams. The drywall lift was well worth the rental price.
Some people use different thicknesses of drywall. We used 5/8 fire code on both layers to add more density.
Here is a half-depth wiring box so that both layers of drywall are not penetrated.
It's always nice to have good friends like Mark here! (if you are looking for a car - he's the guy www.carsense.to )
Using flexible Alex Plus caulk to seal between the drywall and the floor. A small gap should be left when putting in the drywall to allow for this.
A finished corner! (More about doors and windows in the next article)
Harmony Three-in-one underlayment for laminate and engineered wood flooring. They say it has an STC of 59! I doubt it's that high, but I can see how the design would help decoupling.
The engineered hardwood floor installed. I used engineered hardwood because it has some good density and does not need to be nailed down.
The corner after the floor.
What will be the vocal/iso booth after the trim and window was installed.
Hope you enjoyed the pictures and article! If you would like more information, please contact us about consulting with you on building your own home recording studio!