Building a "Room within a room"

Discussion in 'Home Theater Projects' started by Bill Fletcher, Dec 27, 2003.

  1. Bill Fletcher

    Bill Fletcher Stunt Coordinator

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    Building a new house so I have the opportunity to do this right. Any tips on building a room within a room? The new house will have no basement so the HT needs to go on the first floor. One of the kids bedrooms will be directly above so minimizing sound transmission is a must. I've looked at some web sites on floating the floor, using track lighting versus can lights, caulking everything in sight, etc. Wondering if anyone has some experiences they would be able to share.

    Thanks for the help. Bill
     
  2. Wayne A. Pflughaupt

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    You may find this link helpful.

    Regards,
    Wayne A. Pflughaupt
     
  3. Bill Fletcher

    Bill Fletcher Stunt Coordinator

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    Wayne, Thanks for the link. Couple of questions for you.

    At some point the inner room has to connect to the outer room to close it off. What do you do at this connection point to minimize sound/vibration transfer?

    What do you think of this idea? Instead of building a "floating" floor on top of the original one, what if I told the builder not to install the floor where the interior room will go. Then I could install posts into the ground and in between the floor joists and build a new floor just above the floor joists which does not touch them at all. Am I taking this thing too far?

    Thanks. Bill
     
  4. Wayne A. Pflughaupt

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    Bill,

    Construction with a concrete foundation is pretty much the norm here, but I take it that’s not what’s happening at your place?

    If you’re after the absolute best isolation possible, then no - you aren’t taking it too far. Anything you can do to insure the HT room is completely and physically decoupled from the rest of the home is the best way to insure that. To that end, your plan sounds excellent. It will actually be much easier to walk between the HT room and the others in the house if the former isn’t raised.

    Regards,
    Wayne A. Pflughaupt
     
  5. Bobby C

    Bobby C Stunt Coordinator

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    Bill - I hope I'm not high jacking this thread, but I do have a question for Wayne & others as I'm going through some of the same analysis. When installing double drywall, I understand that the sheets will be staggered so that seams don't overlap. But is drywall screwed directly on top of drywall? Or is there some barrier between the sheets? I can imagine using something like a rubber gasket between the sheets or something, but is that what most people do? I can also imagine that if 1 layer is screwed to the studs, the 2nd layer could be glued.

    Also, what about sound absorption boards/panels? In a former life I sold carpet & padding, sometimes we would use soundboards to deaden sound between floors. In my case, this is a basement room so the floor application isn't too important, but what about sound panels on walls or ceilings? Too much absorption & not enough reflection?

    Thanks,
    Bob
     
  6. don costanza

    don costanza Agent

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    Good evening all...
    Bobby C brings up an interesting question. The issue of using carpet pad as a sound absorbing layer, would it work? There are many types of carpet pad being manufactured (different densities) and with the pad in-between the drywall would there be any noticeable difference?

    As the framing of our new house begins on the 5th, I have been in lurk mode to find out what the experts recommend for soundproofing walls. Just want to say I appreciate everyone's insight and willingness to share and hope that I will be able to contribute ideas / suggestions in the near future.

    Best Regards
    Don
     
  7. Wayne A. Pflughaupt

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    Sound absorption and deadening should not be confused with soundproofing. Absorption and deadening has to do with improving acoustics, not preventing sound from leaving a room.

    Don, if you are interested in doing some soundproofing but not able to accommodate a full-blown room-within-a-room, you might take a look at this link.

    Regards,
    Wayne A. Pflughaupt
     
  8. don costanza

    don costanza Agent

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    Wayne,
    Thanks for the input... and the link.

    Best Regards
    Don
     
  9. Bill Fletcher

    Bill Fletcher Stunt Coordinator

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    Wayne - Only about 10% of the houses here have full basements with concrete floors from what I've seen. Rest are half height usually with gravel and plastic laid on the ground. If I can pull this off with the builder, I will basically have a "floating room" not attached to the rest of the house at all.

    Bobby C - Don't worry about hijacking the thread. The more the merrier. I agree with Wayne on screwing in both layers of drywall. I built a HT in the basement of the house I live in now and I glued and screwed two layers of drywall. I wasn't able to build a room within a room though because I didn't have enough space. Here's a site that's got some good info regarding this subject. They recommend a sound blocking material in between the drywall layers. Take a look:

    http://www.acoustics101.com/room_its...0Room%20Itself

    Another suggestion I saw was to tape and mud the inner layer of drywall even though you won't see it. I didn't do this with my room but it makes sense.

    Bill
     
  10. Bill Fletcher

    Bill Fletcher Stunt Coordinator

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    Looking for some clarification on another soundproofing idea that I've seen here. It described making a "home run" from the home theater room ducting back to the furnace. I understanding the concept of not wanting to share ducting with other rooms so that sound can't travel between them, but how would you physically do this? The furnaces I've seen have room for just one big duct going out from the unit. Side branches come out of the main trunk as it passes by a room. Where would this "home run" connect back into the furnace.

    Thanks. Bill
     
  11. Bobby C

    Bobby C Stunt Coordinator

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    Bill - thanks for the link, it was a good read. Actually, taping and mudding the inner layer makes sense for a couple of reasons - obviously for acoustics, but probably just as important is that it would give me a chance to practice my technique and cover up the inevitable mistakes[​IMG].
     
  12. BrettB

    BrettB Producer

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    Bill, regarding the ductwork;

    They are called plenums, basically just a large hunk of ductwork at the furnace/coil to which the supply & return ductwork connects. The idea is to have separate supply & return runs that serve only the HT.
     
  13. Bill Fletcher

    Bill Fletcher Stunt Coordinator

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    Bobby C - That's a good idea, I hadn't thought of that. I did everything in my current HT except lay the carpet and tape & mud. I think I'll try it myself in the new house and practice on that first layer.

    Bill
     
  14. Bill Fletcher

    Bill Fletcher Stunt Coordinator

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    Brett - It looks like on my furnace that there is room for only one plenum. Does that mean I need to have a second furnace to make the home runs to the HT room?

    Thanks, Bill
     
  15. BrettB

    BrettB Producer

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    No, you don't need a second system. Has your system/ductwork already been installed?
     
  16. Bill Fletcher

    Bill Fletcher Stunt Coordinator

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    No, the new system is not installed yet. When I wrote "my system" I was referring to my current house.

    Let me see if I understand this now. The home theater room ducting should connect back directly to the plenum as opposed to branching off of the main duct that runs thru the house?

    Thanks for your help. Bill
     
  17. Bill Fletcher

    Bill Fletcher Stunt Coordinator

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    Brett - any other advice on the HVAC system?

    Anyone else out there that has built a "room within a room" that would be willing to share some tips?

    Thanks. Bill
     
  18. BrettB

    BrettB Producer

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    Yes, that's it, dedicated runs that connect to plenums at the furnace (or as near as possible to the furnace). There really shouldn't be any problem accomplishing this. The design of the house and location of the furnace would have to be quite unique to pose a problem.

    In the rare event you do have an odd situation which does not permit this, put some 90 deg. elbows in the HT runs;

    X-----|___|-------
    ^Grille ^90 deg. elbows

    That's the best I can do [​IMG]
     
  19. Bill Fletcher

    Bill Fletcher Stunt Coordinator

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    Thanks Brett, that's good stuff. I had also seen a recommendation to line the ducting (inside and out)that goes to the HT room. Has anybody done this? What material did you use for lining?

    Thanks. Bill
     
  20. Bobby C

    Bobby C Stunt Coordinator

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    Bill - nice thread, I'm following closely!

    And speaking of lining the ductwork, what provisions should be considered when isulating around the ducts? I have ducts running through my basement ceiling (between joists) for ground floor rooms and I want to insulate the ceiling to help w/ sound. Insulating between joists seems pretty straigt forward but if there is a duct there should I try to pack insulation around it?

    I'm having a HVAC guy come out in the next week & I imagine I'll be running ducts to the HT room from the furnace (plenums). I will be insulating the walls as well, so the same issue for ceiling insulation will most likely apply to my walls.

    Thanks,
    Bob
     

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