I am planning a new construction dedicated theater in upstairs attic area. Would like info as to best insulation ideas and soundproofing for that room. The room will be freestanding --no adjoining rooms. Great room below. What r-value insulation would be best and what type soundproofing---double walls/staggered walls? Was considering double walls of different thickness with blackboard between. Is this overkill? Any comments welcome.

Consider purchasing Green Glue and double drywall. If the studs are 2x4 then use cheap fiberglass R-13 insulation.

Fill the cavities with enough insulation thickness to completely fill the cavity. If that means a layer of R19 and a layer of R13, then so be it. Most of the sound transfer you'll have will be through the floor and the structure. Consider some Duracoustic or Acoustik mat over the existing subfloor and a new subfloor layer and build your walls on top of the new layer.

Agree with the Green Glue and double drywall.

Bryan

Thanks for your comments. Will probably have more questions later. This project will probably have to wait until the fall since the weather here is already hitting 85+.

Any suggestions for web sites to find green glue,acoustik or duracoustic ? There is no subfloor there now. What would you reccomend I put down before subfloor for soundproofing?

Another thought--Has anyone seen info for using 5/8" type X fire rated drywall instead of regular drywall ? I read it has better sound deadening properties. What exactly is green glue?

http://www.greengluecompany.com/

Spend some time reading there, as there is lots of great info on their site.

Guy

hey jbhxray,

5/8" is heavier than 1/2", which gives it better sound isolation at lower freq's, but there isn't anything special or magical about it with respect to sound, just heavier.

i think most all 5/8" i've ever seen around here is type X.


With respect to insulation, the most important thing is that you use some, its less important which type or how thick. In genearl, R13 in walls and R19 in ceilings get youa wfully close to "as good as you'll get". Using thicker won't hurt, and will help (as long as its not really compressed), but its diminishing returns.

Based on what data exists currently, it does appear that normal boring old fiberglass is the best type. For a heaping pile of data sufficient to drive you nuts, but showing alot of comparisons of different types of insulation, go to www.nrc.ca and look for documents called IR761, IR811, IR818.


One thing worth mentioning is that insulation will help you MORE if you use Green Glue or methods like RSIC clips or staggered studs than it will if you use a normal single-wood stud or joist wall or ceiling. The reason for this is that the rigid connection of the stud or joist lets mechanical energy flow pretty easily through the stud or joist to the other side, bypassing the insulation. But if you break this mechanical connection, then sound must attempt to take the airborne path through the insulation.

And, if no ceiling exists (or if an acoustic tile ceiling exists) below the joists, then it is safe to say that the thicker the insulation the better, and one would expect denser types of insulation to yield better isolation.

I can elaborate on those basic points if anybody wishes.

Brian

Thanks----I appreciate the replys

Would like an answer about what can I put down under my subfloor? This room will be over the living room area. I would like to isolate sound from my floors to the ceiling below. There is nothing there now.
Thanks

how big is this attic space your thinking of useing ? show us some pic's so we have a better idea of what you have to work with.

I have space for a 15' x 20' x 9' ceiling. It is totally unfinished now. I have to put in subflooring and build walls and ceiling. Wanted to get ideas as to soundproofing under the subfloor to cut down on noise and vibration in family room below. Plan to use soundproofing above subfloor also. Thick carpet and pad. Ideas appreciated.
Thanks