Author Topic: Soundproofing floor above garage - sheetrock as a flooring layer?  (Read 5446 times)

new dawn fades

  • Guest
Hi,

I am building a music room over my detached garage.  I used staggered studs, cotton-batt insulation in the walls, and two 5/8 sheets of drywall with 1.5 tubes of green glue between each piece.  The floor is currently 5/8" OSB over engineered I-beams.  There is no insulation in the floor joists at the present time.

I am building this on a budget, so I want the most bang for my buck.    This brings me to my question:  how effective would sheetrock be as a flooring layer? 

I am thinking about screwing down a layer of 5/8" sheetrock down over the existing OSB, then applying green glue, then topping it off with another layer of OSB or possibly MDF.   Pad and carpet would go on top of all of that.

Would that be a waste of time/effort?  I understand building mass is crucial..   If my proposal sounds like FAIL, what other low-cost means of soundproofing the floor could I look into?  I cannot build a raised floor in the room. 

Randy S

  • Senior Soundproofing Technical Specialist
  • Global Moderator
  • *****
  • Posts: 819
    • Super Soundproofing Co
Re: Soundproofing floor above garage - sheetrock as a flooring layer?
« Reply #1 on: June 01, 2011, 06:29:47 PM »
Use the OSB and use a 3 TUBE per 4' x 8' of green glue....
You really need to put insulation in the cavity and close up the ceiling below!!! you currently have a drum head for the floor, adding layers above only dampen what enters the drum head...its still a drum head until you close the bottom.

Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

new dawn fades

  • Guest
Re: Soundproofing floor above garage - sheetrock as a flooring layer?
« Reply #2 on: June 01, 2011, 06:48:03 PM »
Planning to close it up in two weeks.  Will use R-30 fiberglass with 5/8" drywall.   Why OSB over sheetrock for the flooring layer?

Randy S

  • Senior Soundproofing Technical Specialist
  • Global Moderator
  • *****
  • Posts: 819
    • Super Soundproofing Co
Re: Soundproofing floor above garage - sheetrock as a flooring layer?
« Reply #3 on: June 01, 2011, 07:00:49 PM »
Due to the glue used in making OSB provides a level of dampening and with green glue in the system this will reduce the reverberation time therefore reducing sound through the system.
Keep in mind no matter what, the main path of sound transmission will be from the screws used to fasten the floor/ceiling system. Unless you float/decouple this will exist.
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

new dawn fades

  • Guest
Re: Soundproofing floor above garage - sheetrock as a flooring layer?
« Reply #4 on: June 01, 2011, 07:02:56 PM »
What about gluing down the first layer of OSB, then apply green glue and screw down the second layer of OSB into the first?   Perhaps the glue would transmit.. just thinking aloud.

Would floating the floor 2" be worth the trouble?  I hate to do this as getting a door for the shortened height will be more costly.

Randy S

  • Senior Soundproofing Technical Specialist
  • Global Moderator
  • *****
  • Posts: 819
    • Super Soundproofing Co
Re: Soundproofing floor above garage - sheetrock as a flooring layer?
« Reply #5 on: June 01, 2011, 07:26:18 PM »
that thought is right on track...visualize drywall like a speaker--- screws like speaker wire or tuning forks---frame work like an amplifier----this is the fastest path through wall/ceiling systems. Not breaking connections is like putting your hand on the speaker while its playing...its still playing just not the same way.

Solution= unplug the speaker.

Mass is for reflecting the airborne sound.  = airborne sound 1129 fps
decoupling is for structural pathways of vibration. =wood framing 13000 fps

So your idea is acceptable for cost. When gluing do 100% coverage 1/4" notch trowel ( not spot gluing!)
And make sure you leave a gap around perimeter of new flooring layers and fill with acoustical caulk. This will reduce the flank to the walls.
 
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040