Soundproofing an Attic Floor...

[TJWillie]

Hi Everyone,

I am currently building a home theater / playroom in our previously unfinished walk-up attic. The room is ~ 14 x 20, and the flat screen TV (most likely a Pioneer 5070HD) will be on the 14' wall.

Unforturnately, this room is situated directly over the Master BR, and partly over the kids BR's.

I am look for a good way to "sound proof" the attic floor.

The floor has 1/2" plywood, and I plan to add another 1/2" of OSB on top of this to help stiffen up the floor. Carpet & pad will go on top of the OSB.

I would like to install some sort of sound absorption product BETWEEN the plywood & the OSB. I am leaning towards a product called :

RB Silent-Tread XL, 2 mm
(http://www.rbrubber.com/index.html?/silent-tread-XL.html

It's fairly inexpensive (~ 25 cents per square foot), and it claims to have an STC rating of 71 ! It sounds like a good product for my needs (& price range), but I'm not sure how something only 2mm thick can work that well.

Please help!! I just finished the drywall, and I am ready to work in the soundproof material and OSB.

Here are a couple of current photos.

Thanks in advance for your comments.

TJ

 

[sholling]

I hesitate to respond because I’m not in the industry, and haven’t listened to every sound reduction solution. What I have experience with is fitting my home with window soundproofing and that’s led to some research on the subject. What I will do is post a link to a soundproofing supplier what has a wealth of knowledge on their site. Hopefully that will be of help.

http://www.soundproofing.org/index.html

 

[mtrycrafts]

Hi Everyone,

I am currently building a home theater / playroom in our previously unfinished walk-up attic. The room is ~ 14 x 20, and the flat screen TV (most likely a Pioneer 5070HD) will be on the 14' wall.

Unforturnately, this room is situated directly over the Master BR, and partly over the kids BR's.

I am look for a good way to "sound proof" the attic floor.

The floor has 1/2" plywood, and I plan to add another 1/2" of OSB on top of this to help stiffen up the floor. Carpet & pad will go on top of the OSB.

I would like to install some sort of sound absorption product BETWEEN the plywood & the OSB. I am leaning towards a product called :

RB Silent-Tread XL, 2 mm
(http://www.rbrubber.com/index.html?/silent-tread-XL.html

It's fairly inexpensive (~ 25 cents per square foot), and it claims to have an STC rating of 71 ! It sounds like a good product for my needs (& price range), but I'm not sure how something only 2mm thick can work that well.

Please help!! I just finished the drywall, and I am ready to work in the soundproof material and OSB.

Here are a couple of current photos.

Thanks in advance for your comments.

TJ

Just a few questions and suggestions.
I don't know anything about that material. It will not keep the low frequency out of the space below, no matter what, unless you turn down the volume a lot.

Is that attic floor joist rated for your loads?
I would pull that 1/2'' in and replace it with at least 3/4" if not thicker. Or, I would build it up with a space between it unless you glue everything together as it will squeak. That 2mm material will prevent it too but just not sure of its real benefits.

Sound will also pass down through wall opening, yet even outlets. The low frequency goes everywhere.

 

[bpape]

Agreed. An STC rating (even though the testing for the spec given goes to 90Hz) is an AVERAGE from 125Hz to 4kHz. It tells you little to nothing about what it will do to stop bass transmission. A 2mm pad is not going to do anything to stop bass - I don't care if it's made of lead.

If you really want to minimize the transfer, you need to pull up the floor (make sure there is full insulation in there while you're at it) and mechancially isolate your new flooring system from the one below. You'll need to rasie it up with new joists on stud isolators and fill the now larger cavity with additional insulation. On top of that, use 2 layers of 3/4" MDF with a layer of Green Glue between them ( a constrained layer damping material that turns vibrations into heat). Also SERIOUSLY consider doubling up the drywall on the rooms BELOW the theater and using Green Glue between the layers.

Even all this isn't going to prevent some transfer if you've got the sub pounding above but can seriously reduce it so that you can listen at moderate levels.

Bryan

 

[TJWillie]

Agreed. An STC rating (even though the testing for the spec given goes to 90Hz) is an AVERAGE from 125Hz to 4kHz. It tells you little to nothing about what it will do to stop bass transmission. A 2mm pad is not going to do anything to stop bass - I don't care if it's made of lead.

If you really want to minimize the transfer, you need to pull up the floor (make sure there is full insulation in there while you're at it) and mechancially isolate your new flooring system from the one below. You'll need to rasie it up with new joists on stud isolators and fill the now larger cavity with additional insulation. On top of that, use 2 layers of 3/4" MDF with a layer of Green Glue between them ( a constrained layer damping material that turns vibrations into heat). Also SERIOUSLY consider doubling up the drywall on the rooms BELOW the theater and using Green Glue between the layers.

Even all this isn't going to prevent some transfer if you've got the sub pounding above but can seriously reduce it so that you can listen at moderate levels.

Bryan

Thanks Bryan & everyone for the helpful comments & suggestions. Yeah, I agree, it doesn't seem like a 2mm pad is going to do much.

The floor joists are in good shape & they are insulated well. I don't think I will be able to mechanically isolate the floor, nor is double drywalling the ceiling below an option at this point. (I guess it could be done later if necessary..)

I have heard and read quite a bit about "GREEEN GLUE", but I have a hard time believing that it would be any better than a heavy layer (perhaps a 1/2 inch thick) of rubber padding.

Also, do you think the MDF is going to make a huge differenct compared to the OSB.

Thanks again for the comments!

TJ

 

[bpape]

Rubber padding is just a shock absorber - and a poor one at that. Green Glue works - I use it all the time. It is designed to never completely dry but stay about the consistency of a superball. It actually converts movement into heat and works well into the subwoofer range (again, be realistic).

As for MDF over OSB - oh yeah. What you need is mass. MDF is way more massive than OSB. To do real isolation, one would do joists, MDF, rubber ribbed mat (about 2lb/sq ft at 3/16" thickness), another layer of MDF, a layer of gypcrete, then pad and more MDF. THAT will stop a bunch of sound way down into the sub range.

Remember that the other thing that you gain with the removal and mechanical isolation is that you make the insulated cavity deeper which has the added benefit of dropping the resonant frequency of the cavity.

Bryan

 

[mtrycrafts]

Thanks Bryan & everyone for the helpful comments & suggestions. Yeah, I agree, it doesn't seem like a 2mm pad is going to do much.

The floor joists are in good shape & they are insulated well. I don't think I will be able to mechanically isolate the floor, nor is double drywalling the ceiling below an option at this point. (I guess it could be done later if necessary..)

I have heard and read quite a bit about "GREEEN GLUE", but I have a hard time believing that it would be any better than a heavy layer (perhaps a 1/2 inch thick) of rubber padding.

Also, do you think the MDF is going to make a huge differenct compared to the OSB.

Thanks again for the comments!

TJ

Whatever you select to place as the 2nd floor, don't place it directly on that 1/2", it will squeak.

 

[TJWillie]

Whatever you select to place as the 2nd floor, don't place it directly on that 1/2", it will squeak.

Yes, that is my plan. At this point, it looks like I am leaning towards the Green Glue. I plan to use 2 tubes of it for each 4x8 sheet of OSB. I will use screws to secure it to the floor joists.

Do you think the GREEN GLUE is sufficient to keep it from squeaking?
Thanks.

 

[mtrycrafts]

Yes, that is my plan. At this point, it looks like I am leaning towards the Green Glue. I plan to use 2 tubes of it for each 4x8 sheet of OSB. I will use screws to secure it to the floor joists.

Do you think the GREEN GLUE is sufficient to keep it from squeaking?
Thanks.

If your coverage is such that the in-between space with the glue is small, that is the space between beads of glue, then the ply may or should not flex enough to contact the 1/2" under it. Make sure your screws are into the joist below it.
What I was driving before about the joust adequacy, is if it is wide enough for its span on load bearing walls below it to carry the dead and live loads. How deep is it, do you know? and its span or distance where you have bearing walls below. I ask because I would bet it wasn't designed for load bearing from a room and its stuff in there?

 

[TJWillie]

The floor joists in the attic floor are 2x10's, and they are 16" O.C. I am certain that these will support the future room. Yes, I am making sure that the existing plywood floor is screwed down to the exising floor joists. Previously, they were just nailed, but I have gone back and installed screws across the entire floor. I will do the same with the layer of OSB.

I spoke with a company a few days ago, and they recommended:

Listed from bottom layer to top:
1 - 1/2" Plywood flooring (existing)
2 - 2 tubes of Green Glue per 4x8 sheet
3 - 1/2" OSB (secrued with screws to the floor joists)
4 - Privacy Ultimate Underlay (1-lb per sq. ft.) -- http://www.soundisolationcompany.com/privacy-ultimate-underlay.php
5 - Carpet padding
6 - Carpet

What do ya'll think?

TJ

 

[kgbagent]

The floor joists in the attic floor are 2x10's, and they are 16" O.C. I am certain that these will support the future room. Yes, I am making sure that the existing plywood floor is screwed down to the exising floor joists. Previously, they were just nailed, but I have gone back and installed screws across the entire floor. I will do the same with the layer of OSB.

I spoke with a company a few days ago, and they recommended:

Listed from bottom layer to top:
1 - 1/2" Plywood flooring (existing)
2 - 2 tubes of Green Glue per 4x8 sheet
3 - 1/2" OSB (secrued with screws to the floor joists)
4 - Privacy Ultimate Underlay (1-lb per sq. ft.) -- http://www.soundisolationcompany.com/privacy-ultimate-underlay.php
5 - Carpet padding
6 - Carpet

What do ya'll think?

TJ

It sounds like you need validation from others for totally ignoring their suggestions. They said MDF; you're using plywood. They said MDF; then you're using OSB.

I'm sorry but these type of posts (where one asks for help, ignores the help, then asks for more help) really get to me...

 

[TJWillie]

It sounds like you need validation from others for totally ignoring their suggestions. They said MDF; you're using plywood. They said MDF; then you're using OSB.

I'm sorry but these type of posts (where one asks for help, ignores the help, then asks for more help) really get to me...

Hey Bud,

Constructive comments & advice are welcome. Your's however are not.

Perhaps YOU didn't read the post correctly. The plywood is already existing, and the OSB is already onsite. I am looking for a cost effective way to sound proof (or at least sound dampen) the floor.

No need for you to reply.

Anyone else is more than happy to share their comments.

Thanks again,
TJ

 

[mtrycrafts]

The floor joists in the attic floor are 2x10's, and they are 16" O.C. I am certain that these will support the future room. Yes, I am making sure that the existing plywood floor is screwed down to the exising floor joists. Previously, they were just nailed, but I have gone back and installed screws across the entire floor. I will do the same with the layer of OSB.

I spoke with a company a few days ago, and they recommended:

Listed from bottom layer to top:
1 - 1/2" Plywood flooring (existing)
2 - 2 tubes of Green Glue per 4x8 sheet
3 - 1/2" OSB (secrued with screws to the floor joists)
4 - Privacy Ultimate Underlay (1-lb per sq. ft.) -- http://www.soundisolationcompany.com/privacy-ultimate-underlay.php
5 - Carpet padding
6 - Carpet

What do ya'll think?

TJ

That underlayment is a sheet product, if I read that link right. That rope caulk confused me a bit. Therefore I don't see a real need for that green glue as the sheet product would prevent the wood floor from contact and squeaking. I would just screw the top sheet right through it and the 1/2'' into the joist.

This should deaden a good bit of the sound, but the walls and structure will still pass the low frequency. That is the toughest to isolate.

 

[bpape]

The mat product you linked to is designed to stop footfall noise under a hardwood floor. I personally would rather see you do another layer of subfloor and green glue. I don't think the pad is going to work very well directly under the carpet.

Doing another layer has benefits in that you'll now have 3 different densities of materials and 2 layers of viscoelastic separation (Green Glue). If cost of the green glue is an issue, you can use 1 tube per sheet on one of the layers.

Unfortunately, isolation is not a cheap proposition.

Bryan

 

[TJWillie]

Bryan,

Thanks again for the helpful information. I like your idea of using another layer of subfloor vs. the underlay product. My only problem at this point is that it will be very difficult (if not impossible) to get any additional 4x8 sheets of subfloor up in the attic. It was a tight squeeze getting them up there before the drywall was installed, but now that it is hung & finished, it may not be possible. Therefore, I was looking for some type of rolled underlayment such as cork, rubber, or now GREEN GLUE as a more practical solution.

You're right though, sound isolation (or even moderate dampening) is not a cheap proposition.

Thanks,
TJ

 

[PerezZaida]

soundproof flooring

Heavy carpets and padding on the floor can help a lot in floor soundproofing. Installing a layer of vinyl foam composite at the sub-floor level and sealing the creases with a silicone adhesive can also decrease the noises to a large extent.

 

[Ted White]

Composite foams under a carpet + pad is largely redundant. The carpet and pad already offer a great deal if impact reduction.

 

[highfigh]

The floor joists in the attic floor are 2x10's, and they are 16" O.C. I am certain that these will support the future room. Yes, I am making sure that the existing plywood floor is screwed down to the exising floor joists. Previously, they were just nailed, but I have gone back and installed screws across the entire floor. I will do the same with the layer of OSB.

I spoke with a company a few days ago, and they recommended:

Listed from bottom layer to top:
1 - 1/2" Plywood flooring (existing)
2 - 2 tubes of Green Glue per 4x8 sheet
3 - 1/2" OSB (secrued with screws to the floor joists)
4 - Privacy Ultimate Underlay (1-lb per sq. ft.) -- http://www.soundisolationcompany.com/privacy-ultimate-underlay.php
5 - Carpet padding
6 - Carpet

What do ya'll think?

TJ

You need to determine how much sound needs to be stopped. Once that is known, it's easier to make recommendations. If all noise must be stopped, give up- it's impossible to do when the theater is mechanically coupled to the lower floors. Bass is generally hard to stop and de-coupling the floor is the best way when the rooms are connected but you'll still have sound transmission from the walls. If you'll be using moderate sound levels unless everyone else is gone, you may be OK with the recommendations you already have.

What kind of door will be used? Consider buying an entry door with the jamb and threshold. It will be weatherstripped and that will keep the sound from leaking past the door. Also, if the door is insulated, it will stop a good amount of sound- solid core doors are great at allowing sound to transmit to the other side.

 

[its phillip]

Considering the thread is over 3 years old, I'm sure the guy finished his attic already