What to do next? Aarggg!!!

[Dr. J]

Here's the scoop.
We just installed the ceiling in our live room in our studio, located
in the basement of our house. The problem is, even though I followed
the construction "prescription" in the wall and ceiling, I can still hear
very slight footfall noise from the floor above.

Worse yet, is the fact that after installing the ceiling, the total ceiling
height is just 7' 1". and adding more layers would make it even more
claustraphobic!

Is this just something most people have to deal with to some degree,
or what would be a good idea to remedy this? more layers?

Here are the layers in the ceiling...

ALL on top of floor joists
1.carpet
2.Oak hardwood flooring
3.Ply sub floor,

Inside, between joists
1. 2 layers 5/8 sheet rock, caulked & sealed
2. 1 layer hard foam insulation (R-5)
3.Air
4.1 Layer R-13 insulation

Under joists, Ceiling layers
1. Res. channel
2. 2 layers of 1/2" SoundStop
3. 1 layer of 5/8" sheetrock

Thanks for any help,
J

[knightfly]

The only place I see that you deviated is in the under-joist layers - putting two layers of sound board does almost nothing for sound reduction - the idea you got from John and confirmed by me, was to use sheet rock-sound board-sheet rock. this would give you more mass, as well as one more "shift" in material for the sound to try and penetrate.

The layers you ended up using are as thick as the ones we recommended, but probably at least 6-8 dB worse performance due to the decreased mass and one less material change.

Short of removing the panels and starting over, I don't know anything that would help much unless you need extra "brownie points" and can afford new carpet upstairs with thicker padding... Steve

[rod gervais]

Steve is right here - the 2nd layer of SB was a mistake....... I also (personally) doubt that you got much out of the hard foam.....

However the lack of mass at the bottom of the assembly is your greatest loss of isolation.

Rod

[Dr. J]

Well, I must admit I did deviate slightly from the plan!
I actually was told by a local acoustics building supplier
that he recommended the 2 layers of sound stop instead
of 3 layers of 5/8" sheet rock because of the dangers of
hanging to much mass/weight on the RC. Guess he's a bozo,
and I should'nt have listened! Probably affraid of legal responsibility
if something fell, in this age of suing for a bad haircut or spilled coffee.

So, anyway, like you've stated, short of pulling the layers down,
(which I will if necessary...) would adding another final layer
of 5/8" gypsum be a good idea & bring me closer to controlling
footfall noise?

Thanks for the help guys, (I'm done deviating btw)
J

[knightfly]

Realistically, another layer of sheet rock would only gain you maybe 3-4 dB, and it would LOSE you another 5/8" of headroom. You STILL would only have one "speed change" in your lower leaf because it would be two layers of sound board and then two layers of sheet rock -

If you back up and do rock/soundboard/rock, you'll have the same headroom you now have with about 9 dB improvement in isolation.

You could improve on that even more if, while the material is off the RC, you replaced the nearly useless hard foam with as much spun fiberglas insulation as will comfortably fit in the joist cavity. Not so much as to compress it tight, but slight compression will only help to dampen your bottom leaf.

I know you don't want to hear this, but that's the best advice I can give you. If your RC is on 24" centers and fastened solidly, there will be no problem supporting two layers of rock and one of sound board. If you were to mount the RC on 16" centers, you'd have enough support (provided your joists were spanned correctly) of supporting even 4 layers of rock.

I try to remind people here NOT to listen to local contractors about sound proofing, because they are NOT aware of how much they don't know. My simple proof of this is that I was in that same place 20 years ago, and screwed up bigtime. In fact, that's what started my whole "quest for silence" thing. The studio I thought was going to be relatively soundproof, actually lets my wife tell from INSIDE the house 100 feet away, which song I'm playing on the piano. Pretty pathetic for someone who "knew it all"... Steve

[Dr. J]

A very happy update if anyone is interested...

After being dismally disappointed with hearing slight footfall noise in my
live room from the room above, I set out to find a solution without using
much more ceiling height (it's only a 7' ceiling now).

A friend of mine who owns a hi-end production studio in town gave me a
solution to try, since I told him what had been discussed on this forum,
and my desire to not rip out the first ceiling if possible.

He had a roll of a material called "sheetblok" that he had used before at
his place, and we put up a 1/8" layer of sheetblok over the last layer of
5/8" sheet rock. Then we "sandwiched" the sheetblok with another & final
layer of 5/8" sheetrock, and tested once again for footfall noise and for
general isolation.

All I can say is wow. The footfall noise is gone, and the only way we can
really hear any noise now is if somebody actually jumps up and down,
or drops something heavy on the above floor from the upstairs.

The negative side is, I did loose aprox. 3/4" of an inch of headroom, but
that seems to be more than worth it now. My friend did say that sheetblok
really isn't effective unless it's put in between multiple layers in a wall
or ceiling. Seems to work fine for me. Heck, I really had nothing to loose!

Peace,
Dr. J

[knightfly]

You found the one use for sheet blok that probably makes it worth it - the stuff is about 5-7 TIMES as expensive as sheet rock per square foot.

However, in your case the ONLY alternative to that would have been to back up and follow my recommendations.

If you're NOT cramped for space, putting a sheet of thinner sheet rock between layers will do real close to the same amount at 1/6 the cost - Auralex won't pay to have such a wall tested of course - it would mean losing too many sales of sheet blok.

Basically, what you did was brute force, which usually works to a degree - just think what you'd have if you had followed the plan, though -

If your friend GAVE you that much sheet blok, at least buy him a case of beer - that stuff runs about $1 per square foot

Glad you're happy with your room now, though - that's the main thing... Steve

[rod gervais]

Dr J,

Steve has this one covered..... tis good your friend gave you that - and i don't think a case of beer touches what you owe him.........

In the end - happy with what you have is the best thing we could hear........ when you finally finish a room - tis then that the real fun begins - after all - this trip people take is not the end - but simply the means to the way - tis the music in the end that really matters.........

Rod

[Dr. J]

Well, I wish I could say that I got it for free, but he gave me a smokin'
deal. In hind sight, I wish I could have backed up easilly, but once I
started visualizing having to rip out all those layers, all those hours... man!

I don't know if others have used sheetblok, or what the general prognosis
on this stuff is, but in my case it worked great.

Now on to funner projects, like finishing the studio lounge and installing
my doors!

Thanks for all the help Steve.

Dr. J