Mass Loaded Vinyl (MLV) under carpet?

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LGHTme

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Just added a large bedroom and loft to the home since we had a lot of wide open space above the living room and we needed more space for the kids. Sound has always been an issue and I’m looking to soundproof the bedrooms above the living spaces.

Since we are already replacing the flooring I think Mass Loaded Vinyl (MLV) will be the most effective and cheapest route. I would just lay some down before the carpet padding. Seems like the standard is 1/8th - 1lb, but I think I want to do 2lb if it's going to help twice as much. Would it be beneficial to go bigger to say 2lb. Since the kids bedroom (2 young boys) will be directly over the living room I’m really looking get the most sound proofing possible. Maybe I go 2lb over the bedrooms and 1lb over the hallways and other common areas?

Another question is if I do add 2lb MLV would that limit me on the thickness of carpet padding and or carpet I can use??

Any and all help regarding the use of MLV under carpet is greatly appreciated.
 

highup

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I've never heard of MLV. Is there a specific product that you can show us?
I'm assuming it's a dense rubber product? If it's not stable enough to allow an installer to nail down tack strip, then you are effectively going to make the padding thicker, or taller. The tack strip that is around the perimeter of the room is 1/4 in thick. Once you get beyond one half inch thickness it will become harder to hook the carpet onto the tack strip because tack strip sets so low next to the padding.
 
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Mark Brown

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Mass Loading is a form of sound proofing that works by retarding the vibration transmission from one surface to the next. As opposed to reflection reductions that dissipate soundwaves (vibration) mass loading "absorbs" them and does not let the energy transfer from, in this case open air, to the wooden structure of plywood subfloor/joist/drywall and back to open air where it will be head once more. It is a great way to prevent sound amplifications from source. I have mass loaded door panels in my car to reduce the vibration they create when someone pumps, oh i dont know, 1200 W RMS of mid bass into them. I will say, where open air exists and you are trying to reduce transmission it works rather well. I am not positive how well it would work under carpet and padding and would be leery of anyone that told me it would work. Tarkett sells a mass loaded PVC with a rubberized/foam backing that claims it reduces sound transmission by 6? dB, I know it is heavy and I suppose it must work or someone smarter than I am would have called them on it.

The thing with mass loading, is that is it is not a cumulative function where more is linear to better. I know for panel loading, there is a 1/3 rule which is to say anything over 1/3 and the returns diminish substantially. I have not really looked into it more than that, but I would highly recommend testing your hypothesis before spending the money. Remember, those who sell to you, do not have your best interest at heart.
 

highup

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It's definitely worth researching consumers and their finished results rather than the company reps.
I got a sample one time of something, probably what you're talking about, and it was less than an eighth of an inch thick. it showed this product being installed before the subfloor. It was draped and hung low between the floor joists and then the subfloor an underlayment were put on top of that. This rubber or vinyl membrane just kind of hung across the joist and it didn't contact the plywood. I'm guessing that method would work substantially better than just laying it directly on the floor surface. It still might work but I'm just not familiar with that product.
Sound transmission is also directed from the plywood into the floor joist via the screws. I'm not sure how to attach plywood to the floor joist without attaching it. 😁
 

LGHTme

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You could always blow some insulation in between the floor joists.

I was looking to apply something that I could do personally and that would be too hard for me to do now that the everything is already in place and just waiting for carpet.
 

LGHTme

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Mass Loading is a form of sound proofing that works by retarding the vibration transmission from one surface to the next. As opposed to reflection reductions that dissipate soundwaves (vibration) mass loading "absorbs" them and does not let the energy transfer from, in this case open air, to the wooden structure of plywood subfloor/joist/drywall and back to open air where it will be head once more. It is a great way to prevent sound amplifications from source. I have mass loaded door panels in my car to reduce the vibration they create when someone pumps, oh i dont know, 1200 W RMS of mid bass into them. I will say, where open air exists and you are trying to reduce transmission it works rather well. I am not positive how well it would work under carpet and padding and would be leery of anyone that told me it would work. Tarkett sells a mass loaded PVC with a rubberized/foam backing that claims it reduces sound transmission by 6? dB, I know it is heavy and I suppose it must work or someone smarter than I am would have called them on it.

The thing with mass loading, is that is it is not a cumulative function where more is linear to better. I know for panel loading, there is a 1/3 rule which is to say anything over 1/3 and the returns diminish substantially. I have not really looked into it more than that, but I would highly recommend testing your hypothesis before spending the money. Remember, those who sell to you, do not have your best interest at heart.

Yeah I've used MLV quit a bit in the past in my cars as well. I once owned a truck that had 2, Gigahertz of power going to 14 speakers. The different the MLV made in the panels is amazing.

The reason I thought about using it for carpet is although expensive it is effective.

Here is some info I found online prior to posting here which gave me the idea. I'll probably purchase the thicket stuff and lay it down and let the carpet installer just put down their standard underlay on top of it.

6. Optional: Lay Down Some MLV. Before you go in with softer padding, you should consider laying mass loaded vinyl directly on top of your subfloor. If you’re worried about airborne noise, MLV can thicken up your floor. So even if you didn’t have insulation under the subfloor, it wouldn’t matter. Mass loaded vinyl is a fantastic soundproofing material, whether you want to use it under or over flooring surfaces, or even under the subfloor. It can also help you soundproof walls, ceilings — you name it, you can probably attach MLV to it. In this case, the dense material would really make your floor more impenetrable to airborne noise as well as absorb any impact noise footsteps might produce. If you decide to include MLV, you could order just enough to cover the entire surface of your floor. You’ll probably have to let the material settle for a few hours after you roll it out. When it’s as flat as it can be, use double-sided carpeting tape or nail the edges into the subfloor. If you end up topping it off with another carpet underlay, you probably won’t need to connect the MLV pieces with tape. However, if you want to use MLV on its own, tape it down to prevent airborne noise from slipping through the floor. You could even use a professional soundproofing tape Dynatape.


 

LGHTme

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It's definitely worth researching consumers and their finished results rather than the company reps.
I got a sample one time of something, probably what you're talking about, and it was less than an eighth of an inch thick. it showed this product being installed before the subfloor. It was draped and hung low between the floor joists and then the subfloor an underlayment were put on top of that. This rubber or vinyl membrane just kind of hung across the joist and it didn't contact the plywood. I'm guessing that method would work substantially better than just laying it directly on the floor surface. It still might work but I'm just not familiar with that product.
Sound transmission is also directed from the plywood into the floor joist via the screws. I'm not sure how to attach plywood to the floor joist without attaching it. 😁

Thanks for the info. MLV is a thick rubber substance that although isn't used a lot for carpet do to costs is used from time to time. There are companies that make underlayment with a thin layer of MLV attached, but wow they are really expensive for the thinnest possible amount of MLV they are adding.

 

Mark Brown

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It's definitely worth a try right?
The theory is sound. After thinking more on it, if my double walled sub box filled with sand can reduce vibration then why not MLV under carpet ?
You know the more I think about it...... all you are trying to do is add a dampening layer between the source and the structure. One way to know for sure lol

If you do go through with this, you make sure to let us know because now I am curious myself. If I can gain knowledge at others expense, I am all over that ;)
 

highup

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I can't believe I read through that entire article. I think the writer watched someone install carpet once and is now describing the procedures as best he or she remembers. 😁
Towards the end of where it mentions quiet walk underlayment, I would totally forget about that. it's designed to deaden the clipity clip sound when you were walking with hard sole shoes on hard surface laminate floors. I think all that it would do is add unwanted additional height to the carpet padding.
There's also some mention of soft foam padding. It's soft because there's less foam density. Logic would say that dense phone would be better to reduce sound transmission. Dense carpet padding is best for the carpet life. You don't want the total thickness of the padding to exceed 1/2 inch.
If that sound deadener is 1/8 in thick, you don't want to add one half inch thick pad over the top of that unless you put 1/8 inch shims under the tack strip. That sounded there might work under some circumstances but without seeing some sort of clinical test with two identical carpets into identical rooms and comparing the results......... Well, let's just say I'm not sold on this material unless it's installed loosely draped between the joists, and under the plywood.
You might be better off to just buy the heaviest rubber slab padding that you can find. It's very dense and very heavy and it will not be cheap.
That said, without an actual acoustic test you're just guessing .......or should I say, I'm just guessing. 😁
 

highup

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It's definitely worth a try right?
The theory is sound. After thinking more on it, if my double walled sub box filled with sand can reduce vibration then why not MLV under carpet ?
You know the more I think about it...... all you are trying to do is add a dampening layer between the source and the structure. One way to know for sure lol

If you do go through with this, you make sure to let us know because now I am curious myself. If I can gain knowledge at others expense, I am all over that ;)
I'm trying to figure out what sounds this product would dampen. I doubt it would deaden the sound of walking on the floor because the carpet and some good padding should do that.
 

LGHTme

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It's definitely worth a try right?
The theory is sound. After thinking more on it, if my double walled sub box filled with sand can reduce vibration then why not MLV under carpet ?
You know the more I think about it...... all you are trying to do is add a dampening layer between the source and the structure. One way to know for sure lol

If you do go through with this, you make sure to let us know because now I am curious myself. If I can gain knowledge at others expense, I am all over that ;)

Yeah, the product itself is amazing and very functional. Since I've used the sheets in the past I already know how well it works. I was leaning toward the thicker 2lb rolls over the 1lb roll.

 

LGHTme

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I can't believe I read through that entire article. I think the writer watched someone install carpet once and is now describing the procedures as best he or she remembers. 😁
Towards the end of where it mentions quiet walk underlayment, I would totally forget about that. it's designed to deaden the clipity clip sound when you were walking with hard sole shoes on hard surface laminate floors. I think all that it would do is add unwanted additional height to the carpet padding.
There's also some mention of soft foam padding. It's soft because there's less foam density. Logic would say that dense phone would be better to reduce sound transmission. Dense carpet padding is best for the carpet life. You don't want the total thickness of the padding to exceed 1/2 inch.
If that sound deadener is 1/8 in thick, you don't want to add one half inch thick pad over the top of that unless you put 1/8 inch shims under the tack strip.

Ok the weight of MLV I've opted to use is 2lb which should have a Sound Transmission Class (or STC) raiting of around 30-32. This will add 1/4" thickness to the floor. If I don't want to exceed 1/2" total thickness I'll start looking for some dense padding that will keep my under 1/2" high overall.
 

highup

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Fast If the product is extremely dense and the tack strip can be nailed on top of it then you won't have any problem with 7/16 or 1/2 inch pad. The problem would be if the tackstrip is already in and you put one quarter of an inch of sound deadening next to the tack strip and then added the path.
You could also add one quarter inch plywood strips underneath the tack strip and but your sound deadening up to the tack strip. 1/4 in plywood is most likely, more dense and more stable than the membrane that you have. It's hard to know it's characteristics without having a piece of it in my fingers.
Most carpeting tends to be close to 5/8 to 3/4 of an inch thick. Add to that 3/4 of an inch of padding and sound deadener brings you to an inch and a half and you'd probably want to cut the doors at 1and 3/4 inches. If you have baseboards installed, the carpet thickness plus the shimmed up tack strip thickness might bury 1/2 the baseboard height.
You have a good idea what the product might be able to do. I'm just tossing in things to think about if you do it. If you're stepping into the room from a wood floor or something like that, you're also going to be stepping up a bit higher usual. That might require another method of finishing off the carpet edge at the doorway.
 

highup

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You aren't doing this just because the kids listen to rap music are you? if it is I'd put three layers of quarter inch sound deadener. 😁
 

LGHTme

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Fast If the product is extremely dense and the tack strip can be nailed on top of it then you won't have any problem with 7/16 or 1/2 inch pad. The problem would be if the tackstrip is already in and you put one quarter of an inch of sound deadening next to the tack strip and then added the path.
You could also add one quarter inch plywood strips underneath the tack strip and but your sound deadening up to the tack strip. 1/4 in plywood is most likely, more dense and more stable than the membrane that you have. It's hard to know it's characteristics without having a piece of it in my fingers.
Most carpeting tends to be close to 5/8 to 3/4 of an inch thick. Add to that 3/4 of an inch of padding and sound deadener brings you to an inch and a half and you'd probably want to cut the doors at 1and 3/4 inches. If you have baseboards installed, the carpet thickness plus the shimmed up tack strip thickness might bury 1/2 the baseboard height.
You have a good idea what the product might be able to do. I'm just tossing in things to think about if you do it. If you're stepping into the room from a wood floor or something like that, you're also going to be stepping up a bit higher usual. That might require another method of finishing off the carpet edge at the doorway.

Thanks for the tips. Yes, the tack strip will go right on top of the MLV. Since this is new construction and they just laid the ply wood I have a lot of flexibility. I will also carpet the entire area and loft the same so height shouldn't be an issue as the new "modern" baseboards with crown end up really high around an inch and a half.
 

LGHTme

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You aren't doing this just because the kids listen to rap music are you? if it is I'd put three layers of quarter inch sound deadener. 😁
hahaahah basically 2 growing boys 6 and 2 directly over the living room. The house is fairly new and they left the entire living room open so when you enter it gives a "grand" look of lots of open space, but I rather have another few hundred feet of living space...
 

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