Author Topic: building a home theatre on a budget: Help!  (Read 2946 times)


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building a home theatre on a budget: Help!
« on: December 25, 2006, 05:57:31 PM » I'm about to embark on building a home theatre in my basement.  I am fortunate in that I have enough room to build a room within a room, but need some assistance, probably mostly on the construction of the ceiling and then some clarification on the floor:

Walls will be 2X4 and 2X6 construction (depending on which wall and space constraints).  2 of the four walls will have dead zones behind them with limited space and poured concrete walls behind.  The other two walls will have additional living quarters on the other sides of them.  (One a hallway and the other a workout room).  I plan to set the wall plate on iceshield material (primarily an edpm rubber) and secure with concrete anchors.  Walls will be erected over this plate and either secured to the TGI's of the floor above, or freestanding and supported by each other (suggestions on this are welcome).  Outer shell will be 1/2" drywall installed traditionally.  Cavities will be filled with R-13 fiberglass batting (will consider cotton batting for wall next to workout room and ceiling for improved sound deadening...but cost is a factor and some audible noise into hallway is not of grave concern.  Interior walls will have green tape covering all studs and base and ceiling plates with 1/2" drywall, a layer of green glue (need some recommendations on best source and amount which should be used) and a final layer of 1/2" drywall.  I am willing to consider soundboard, but cost may be too much.  Additionally, I would consider crete board for greater density....but don't know pros and cons and haven't priced all materials yet.

Now...on to the two areas I have the least info about:

1) concrete floors:  Since most information I've dug up refers to traditional floors, I know little of what I absolutely "must" do so as not to be dissappointed in the end when building over concrete.  It is a 3" slab over 3-4" gravel over sand.  I need an education not only on how much this might transmit sound thoughout the rest of the home if I do nothing more than cover with 3/4" OSB, pad, and carpet as opposed to going further, but need to know a little more of how various options may impact the quality of sound in the theatre itself.  I wish to keep from raising the elevation more than 1" at MOST on the lower section, and no more than about 8" on the riser.  So....will the sound be "dead" if I do not raise the lower level floor on furring strips?  Do I need that "give" for the sound to be "alive"?  Or can I just go with a vapor barrier, 30lb felt, and 3/4" OSB and be done with it?  Again...cost is a hurdle, but time is not.  If giving "some suspension" to the floor improves the sound, I might consider 1/4" furring strips and could even cover with green tape if that adds something.  The riser area I could also use some input.

2) the ceiling:  LOTS OF QUESTIONS HERE:  What is my best "cost effective" option?  This is probably where I am most concerned about sound traveling where I don't want it.  Floor above is either 3/4" plywood, carpet pad, and thick carpet, or in another area is is the same subfloor, with 3/8 crete board, and 1/4" tile.  Joists are TGI's.  I have sufficient head room, but think any kind of isolation clips will be cost prohibative.  Additionally, I plan to have some funky trays and dropped areas of ceiling to try and make the ductwork I have to work around unnoticable.  So.....can anyone offer a poorman's solution to dealing with the ceiling?  Can I build the general "shape" with dropped sections by nailing to the existing TGI's and then use green tape and secure directly to that?  Maybe two layers and insulate with cotton batting above?  Lastly, is there any huge impact to tying the walls to the ceiling, or trying to keep it self supporting? 

Thanks a million.  As I learn more I'll likely have more questions.



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Re: building a home theatre on a budget: Help!
« Reply #1 on: December 26, 2006, 10:10:47 PM »
You should worry more about the ceiling than the slab.  The slab is heavy and by the time the sound passes to (and through) the basement walls (more massive still) there probably won't be much sound escaping upstairs.  Besides, you can always do something with the floor later.

The ceiling, however, is your shortest and hence, leakiest sound path.  You should use the same treatment as the walls - insulation, double drywall.  If you can't afford sound clips ($1.60/sq.ft.) then just use hat channel (less than 10 cents/sq.ft.) installed perpendicular to the studs.  I see you're planning on using integrity gasket, but seal up the seams and gaps of the drywall as well. 

Also, on the walls:  Instead of using iceshield, get a roll of 'sill sealer'.  It will break the vibration better. 

Not exactly sure what you mean by 'free floating' walls, but unless you plan on making them shear walls with OSB and tying the tops together somehow, they'll probably fall down on your head.  Tie them into the TJI's, in a way that won't transfer much vibration.  Improvise some kind of rubber pad system.