Insulate basement ceiling for nosie?

[The Fake Cheap]

I'm in the process of finishing my basement.  Next step is for drywall to go in on the ceiling and interior walls, exterior walls are already drywalled.  I've been asking around a lot and checking on line, but there is a lot of mixed opinions about insulating the ceiling for sound purposes.   So I wanted to ask the experts here on the MMM forum.  Is it worth it to insulate a basement ceiling for sound purposes?   I will add that the master bedroom and my son's bedroom are directly above this area.  The area is 13ft by 21 ft.  I don't have drums I'm going to bang on down there, but I do watch a lot of late night basketball and play the occasional video game, so if I could have the TV at a volume that would be more than a whisper, that would be super.  I will also add that my wife is a light sleeper.  One last piece of information is that the ceiling as 6 LED pot lights, so there would be gaps in the insulation in these 6 areas around the pot lights, so sound is going to penetrate there.   Any information or opinions would be appreciated.

[Syonyk]

If you're in there and it's not that expensive to add some mass to damp the sound, go for it!

It's going to be heavily dependent on the house and nature of the noise (and sensitivity to the noise), but I can't think of a situation in which less noise damping in a house would be better than more.  It's also thermal mass tied to the floor, which might help with day/night temperature swings.

[zolotiyeruki]

When I finish our basement, I'm *definitely* going to invest in some insulation to dampen the sound.  You might also consider sound-isolating furring channels for hanging the drywall on the ceiling.  You won't be able to silence it all, but it'll go a long way.  My brother just did fiberglass batts between the joists, and you can hardly hear *anything,* even when the kids are going nuts down there.

[Greg]

Air leaks also transmit noise fairly well, so try to seal up any framing penetrations.  Rock wool, especially the super dense stuff, does a better job than plain fiberglass insulation when it comes to noise dampening.  Furring channels, fiberboard panels behind the drywall, all will help with noise. If you plan to have a game or other entertainment on at night, you'll want to turn down your subwoofer, as that frequency can transmit through most materials more easily.

[Hummer]

Do 2 layers of drywall for sound blocking.

There are 2 different things with sound. There is sound absorption and sound blocking. Usually you want both. The insulation will help with sound absorption but sound can still carry through the floor joists. Ideally you want an air gap between the floor joists and the drywall as well so the sound doesn't carry.

[The Fake Cheap]

Looks like the word on the street here is for me to add the insulation/soundproofing.  I've done more research on it and I'm pretty sure I'm going to go with Roxul, opposed to regular insulation.  It is about 3 times the cost, but my total cost is only about $250, and if I'm going to bother doing it, I want to do it the best way.  I'm going to run a test to measure decibel level  before and after the ceiling goes on.  I'll post the results, in 2-8 weeks.

[Mirwen]

I used Roxul when I renovated my master bath.  It does reduce sound but not eliminate it.  To get true soundproofing you would need the drywall spacers and that's a whole other level of PITA.  I think you'll be happy with the Roxul for your needs.  It's very easy to work with.

[Hummer]

I had a thread on this recently. See the link.

http://forum.mrmoneymustache.com/do-it-yourself-forum!/sound-proofing/msg450544/#msg450544

Since our ceiling was already finished and I didn't want to tear down the ceiling and re-install gyproc, I ended up adding a drop T-bar ceiling with Roxul safe and sound insulation. I simply installed the T-bar drop ceiling about 6 inches below the current ceiling, added 3" bats of roxul safe and sound and I was done. I simply sat the 2x4 bats of insulation on top of the 2x4 T-bar tiles. There is a 3" air gap and since the ceiling is hanging there is no sound transmission through the air gap.

It has stopped 95% of the noise I was having transmit to the upstairs.

The total cost was about $1,500 for approximately 750 square feet so $2 per square foot.

[Sojourner]

Check out this publication.  It describes the STC (sound transmission class) of various wall and ceiling assemblies.  How the architects specify it.   Diagrams of assembly sections are provided, so if you build it that way, the STC rating indexed should result.  Also note another rating is IIC (Impact Isolation Class) that also comes into play, having to do with impacts against an assembly and how that type of sound is transmitted.

http://goo.gl/HIbjdx