How to reduce noise to floor above from this basement theater?

[tigerninety]

Hello,

I apologize if these questions are answered elsewhere and I invite pointers to other threads that will help. I've read through many of these threads and don't feel that I quite understand enough to get the information I need.

We have a 1935 Cape that has a cinderblock wall foundation all around the basement. It's a low ceiling -- about 6'5" at its tallest -- and is effectively divided in half by (what is probably) basic 2x4 framing plus gypsum.

We're in the process of finishing the entirety of the basement; half will be a laundry room and half a media/entertainment room. Unfinished, we've used one half for a long time to accommodate: a 135-in screen, Panasonic AE4000 projector, Onkyo-driven seven-speaker Athena setup, plus an Outlaw LFM-1 subwoofer. When finished, we'll basically have the same HT setup.

Around the exterior walls, the plan is to apply 2-in thick XPS directly to the cinder block, followed by 2x3 (with additional unfaced batt in between the studs), covered with standard gypsum. (This is part of a moisture/mold mitigation effort.)

My major question is about reducing sound transmission up to the main floor. Right now, the audio from the theater seems to pass right through the ceiling (completely unfinished joists) into our dining room and kitchen above (it's like you're having dinner and a movie....at the same time in the same place).

So, what are our best options for the ceiling in the basement? It's a low ceiling, so we can't "afford" solutions that take too much vertical space. Also, there seems to be some debate about the merits of installing batt insulation above a conditioned basement.

One leading option is installing acoustical ceiling tile (e.g. from USG) held in place by a system like CeilingLink. We'd probably omit any batt insulation because of the (perceived) debate over insulating a ceiling above a conditioned space. Also, I think I've read that batt insulation doesn't do much in terms of sound attenuation.

Another option would be to use a standard drywall ceiling. And, another option would be to use a specialized drywall, like QuietRock (which I haven't priced, yet).

So, bottom line, if our major concern ISN'T sound transmission to an ADJACENT room, but rather to a room above, AND we've got height issues (and we are on a budget), what are your recommendations?

Thank you very much!

Tiger

 

[macddmac]

What size/ spacing are the floor joists? Usually, some r-30 batts will soak most of it up... Ducting is another culprit as it will transmit sound far better than a soup can and string.
You can go with a sound isolating drywall setup, but the investment is substantial and the return may be little more than the r-30 and drywall or acoustic panels. would provide, especially if there's ducting in the vicinity.
Cheers, Mac

 

[Alex2507]

What's the argument against batt insulation?

Fill the joist cavity with insulation. Cover with drywall. QuietRock is ~ $45 /sheet as opposed to $10 a sheet if my info is good. Totally worth it since a higher STC is your goal.

T-bar ceilings (acoustical tile) require a 4" drop from your lowest height. The main tee is ~ 1-7/8" and you need clearance to get the tile above that. Bad idea when you start with a low height of 6'5".

That will take care of high frequency noise best and leave you with a lower frequency still coming through but at least it won't be like you're right there.

Edit: whoops, sorry. I never heard of or used ceilinglink before. Not sure what STC you could expect from that but I don't think it will touch quiet rock. not sure though.

 

[Alex2507]

... another thing I'm not sure about is if Resilient Channel can be used in an overhead application.

... oh, look what I found!

The therma fiber they used is only better in the respect that it 'fills' the cavity better. That is the key regardless of the density of the fiberglass. Those guys could have done better.

 

[ImcLoud]

Acoustic Solutions | Soundproofing Material | Soundproofing Products

I used this companies stuff when we insulated the office at my garage... I built my shop, and then added the office, but we only used thin metal studs, and sheet rock with no insulation since the entire building is heated... But I soon found out that while the girls were in the office making phone calls, if I started a truck or machine in the garage, it sounded louder in the office than the garage... Big problem... So these guys sold me a bunch of stuff.

We got the tape, caulk, 1/4" panels, there fiber rolls of insulation, and the wall covering. we only had to do 1 wall and only the office side was sheetrocked so it was easy to do and I figured do as much as I can since I could hear how loud the problem was...

Anyway after we finished I had to put an intercom, because even with the door open you cant hear between the office and garage!!! That stuff works..

 

[tigerninety]

Sources of uncertainty on basement ceiling insulation

Hello,

Thanks for your reply.

Regarding the argument against insulating basement ceilings with batt insulation, there are a couple of links I would post, but I'm apparently not allowed to do that until I've posted five messages or more.

The short version of the argument seems to be that insulation in the ceilings keeps warm air from reaching the basement, thereby increasing the risk of mold and pipe freezing. Now, that argument may make some assumptions about basement heating that may not apply in various circumstances and I can't tell whether they apply in mine or yours. But those are the sources.

Also, the basement ceiling is about the only place that DOE does NOT recommend insulating in a house. (It's not that they recommend against it, it's just that they recommend insulating just about everywhere else.)

Thanks!

Tiger

What's the argument against batt insulation?

Fill the joist cavity with insulation. Cover with drywall. QuietRock is ~ $45 /sheet as opposed to $10 a sheet if my info is good. Totally worth it since a higher STC is your goal.

T-bar ceilings (acoustical tile) require a 4" drop from your lowest height. The main tee is ~ 1-7/8" and you need clearance to get the tile above that. Bad idea when you start with a low height of 6'5".

That will take care of high frequency noise best and leave you with a lower frequency still coming through but at least it won't be like you're right there.

Edit: whoops, sorry. I never heard of or used ceilinglink before. Not sure what STC you could expect from that but I don't think it will touch quiet rock. not sure though.

 

[Rickster71]

The short version of the argument seems to be that insulation in the ceilings keeps warm air from reaching the basement, thereby increasing the risk of mold and pipe freezing.

I'd search further for more reliable links. The info you have doesn't sound reliable.

Heat doesn't doesn't naturally travel downward, it rises.
Can I safely assume you'll be heating your theater? If so, the contention from your info won't apply.

Now, that argument may make some assumptions about basement heating that may not apply in various circumstances and I can't tell whether they apply in mine or yours. But those are the sources.

Also, the basement ceiling is about the only place that DOE does NOT recommend insulating in a house. (It's not that they recommend against it, it's just that they recommend insulating just about everywhere else.)

Never heard of "Not" insulating a basement ceiling.(the living space floor)
Keep in mind, you are insulating for sound attenuation, with it's thermal properties being a side benefit.

 

[Rickster71]

... another thing I'm not sure about is if Resilient Channel can be used in an overhead application.

Hey Alex, I'm remember seeing it on a few jobs, rubber pads that help decouple the Hat Track from the joists. To further deaden sound transmission.
I'll search a little.

 

[Alex2507]

Hey Alex, I'm remember seeing it on a few jobs, rubber pads that help decouple the Hat Track from the joists. To further deaden sound transmission.
I'll search a little.

RC is only 1/2 inch.

 

[Rickster71]

RC is only 1/2 inch.

Yes, it's a thin rubber pad that went under it.
Hat Track ...RC same thing.

 

[Rickster71]

This isn't exactly what I saw,
GenieClip by Pliteq | GenieClips | Resilient Sound Isolation Clips
The general principle is the same.
They could've been cutting strips of ice & water shield and doubling it up.
Or something like that...

 

[tigerninety]

I'd search further for more reliable links. The info you have doesn't sound reliable.

Heat doesn't doesn't naturally travel downward, it rises.
Can I safely assume you'll be heating your theater? If so, the contention from your info won't apply.




Never heard of "Not" insulating a basement ceiling.(the living space floor)
Keep in mind, you are insulating for sound attenuation, with it's thermal properties being a side benefit.

Hello,

From my research, which I don't claim to be complete or authoritative or I wouldn't have asked, it seems that it's not as simple as "heat rises."

The second law of thermodynamics is: "heat flows spontaneously from a hot body to a cool one." This is one of the reasons you put hot soup in a thermos; the heat would otherwise flow to the cooler air around an uninsulated container, not the other way around. (Cold doesn't flow to a warmer space without additional energy; otherwise we wouldn't need powered refrigerators and freezers.)

So, at the floor above the basement, IF THE BASEMENT IS COOLER THAN THE AREA ABOVE THE FLOORS, the warm air at the floor will actually fall to the basement and insulation in the joists will reduce that flow. This is why (apparently) it is so important to insulate the above-ground walls of your basement (because otherwise, the warm air transferred into basement will cool rapidly against the walls exposed to the outer above-ground walls, which -- in northern climates anyway -- are much colder than the below ground walls). It also explains why it is so important to insulate the basement walls, to raise the overall temperature of the basement.

So, if I understand the argument, if the unheated basement ceiling is insulated, the heat that would normally flow into the cooler basement and raise that temperature overall is hindered from flowing into the basement and the overall temperature of the basement falls. Hence, the increased risk of mold from condensation and frozen pipes.

Now, if the basement is heated to the same temperature as the floor above, then this problem shouldn't exist.

Our basement will be heated only on occasion, when we go down to watch movies or fold laundry. So, this issue may apply.

Thoughts?

Thanks!

Tiger

 

[Adam]

Hi, Tiger. Heat can flow in any direction, regardless of medium (e.g. air, vacuum), as you stated. Hot air, on the other hand, does naturally rise because of buoyancy effects. Hot air is less dense than cold air, so cooler air sinks and hotter air rises (when in a gravitational field, all of you engineers out there ).

So, yes - insulating a basement ceiling can reduce heat transfer from the upper floor to the basement, but it's not because the hot air will sink to the basement floor. You could put in ventilation fans that would move the air around in the basement, which would circulate the hotter air around.

 

[Rickster71]

Hello,

The second law of thermodynamics is: "heat flows spontaneously from a hot body to a cool one."

Agreed, up and sideways not as much downward.

Most people that don't insulate their basement ceilings experience cold feet during winter.
Sounds like you're over-thinking, what are really just standard construction techniques.


I don't think a discussion forum is your best bet for reliable info.
My $0.02 would suggest a site like : Insulation | Department of Energy

 

[TLS Guy]

Hello,

From my research, which I don't claim to be complete or authoritative or I wouldn't have asked, it seems that it's not as simple as "heat rises."

The second law of thermodynamics is: "heat flows spontaneously from a hot body to a cool one." This is one of the reasons you put hot soup in a thermos; the heat would otherwise flow to the cooler air around an uninsulated container, not the other way around. (Cold doesn't flow to a warmer space without additional energy; otherwise we wouldn't need powered refrigerators and freezers.)

So, at the floor above the basement, IF THE BASEMENT IS COOLER THAN THE AREA ABOVE THE FLOORS, the warm air at the floor will actually fall to the basement and insulation in the joists will reduce that flow. This is why (apparently) it is so important to insulate the above-ground walls of your basement (because otherwise, the warm air transferred into basement will cool rapidly against the walls exposed to the outer above-ground walls, which -- in northern climates anyway -- are much colder than the below ground walls). It also explains why it is so important to insulate the basement walls, to raise the overall temperature of the basement.

So, if I understand the argument, if the unheated basement ceiling is insulated, the heat that would normally flow into the cooler basement and raise that temperature overall is hindered from flowing into the basement and the overall temperature of the basement falls. Hence, the increased risk of mold from condensation and frozen pipes.

Now, if the basement is heated to the same temperature as the floor above, then this problem shouldn't exist.

Our basement will be heated only on occasion, when we go down to watch movies or fold laundry. So, this issue may apply.

Thoughts?

Thanks!

Tiger

Your physics is way off base.

There will always be a thermosyphon for every gas and liquid based on density. Hot gasses and liquids are less dense and will go to the top in a gravitational system, and vice versa. Cold air or gas being denser will sink to the bottom. To reverse a thermosyphon does require some energy, but just a simple pump, not a heat exchanger like an air conditioner.

Now, if you want to cool a gas or liquid to a point below ambient temperature of the surroundings, then yes, you have to pump heat energy against a gradient and that requires more energy beyond a simple pump. So you are increasing the outside ambient temperature to cool the inside structure.

A thermos is totally different all together. This is passive and uses a vacuum which does not conduct heat, to slow the egress of higher outside ambient temperature working its way inside to heat up the contents.
It works equally well the other way round to slow egress of heat energy inside to a cooler outside ambient temperature. Home insulation works the same way.

There may be some validity to the humidity argument of insulating a cold basement, if it does not have HVAC. Warm air holds more water vapor than cold air. So if warm moist air could mix with cold saturated air in a ceiling space there could be the potential for a moisture problem.

However, a properly designed HVAC removes moisture as it cools and if the whole house is under HVAC control I doubt there would be a problem in summer.

For this reason in the winter a basement should not be allowed to cool significantly below the level above. If things are closed up you can have a definite problem in that case for obvious reasons.

If pipes are freezing in a ceiling space then you have much bigger problems than just moisture.

That is your physics lesson for today.

 

[livern98]

Any body have a bad experience using quiet rock, performance wise?

 

[Alex2507]

This isn't exactly what I saw,
GenieClip by Pliteq | GenieClips | Resilient Sound Isolation Clips
The general principle is the same.
They could've been cutting strips of ice & water shield and doubling it up.
Or something like that...

The Product Brochure PDF link in that link has some really good info.

Hat Track ...RC same thing

Not at all. Hat track/high hat/furring channel have 2 mounting legs but RC has only 1.

Anyway I learned something here and it saved me some wasted effort on my own ceiling so thanks.

 

[GIK Acoustics]

Any body have a bad experience using quiet rock, performance wise?

Not worth the price at all - just go for an extra layer of drywall instead..

 

[Rickster71]

The Product Brochure PDF link in that link has some really good info.



Not at all. Hat track/high hat/furring channel have 2 mounting legs but RC has only 1.

Anyway I learned something here and it saved me some wasted effort on my own ceiling so thanks.

Oh, I see it now.
I only saw the RC from one side and it looked like hat track.

 

[Alex2507]

Not worth the price at all - just go for an extra layer of drywall instead..

I thanked you for your opinion ... but ... we have a difference of opinion. My take on it has to do with application. In my situation I am going with your advice because my room is open to a whole mess of single layer ceiling so I'm not going to spend an extra couple of hundred silencing one small part. If the room was closed off ... I think it would be worth it.

Edit: Please feel free to post some links with tests and graphs like Rick did.
I may learn slow but I do learn.