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Author Topic: Plexiglass Window Insert Question  (Read 4397 times)

Mike-Del

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Plexiglass Window Insert Question
« on: August 11, 2016, 05:52:08 PM »

Hi All,

First of all, I'm glad I found this forum and learned quite a lot from reading all the posts. I have my two bedrooms facing street, normally it's ok and I don't hear too much traffic noise, but at night or early morning, when people with pick-ups or other loud cars accelerating through the street, it is quite loud in the room (around 70 db with window closed), and affect my sleep sometimes. I do already have double-pane windows installed (not sure which brand, we just moved into this house). My bedroom window is fairly wide, about (36" x 95"). My questions are:

1. Is there anything or test I can do to make sure window, instead of the actual wall, is the problem?

2. I plan to get a 1/4 window grade plexiglass and try out the magnetseal concept, is my window too large for have one piece plexiglass? should I put some reenforcement bars on the plexiglass? if so, what would you recommend?

3. I will order the magnetseal kit, but if I want to quickly try out the concept, is theres some foam or something I can buy to provide sealing while I hold the plexiglass in place, I just want to see how good the noise cancellation would be with this concept before I receive the magnetseal kit next week.

Thanks, and you guys are awesome.

Randy S

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Re: Plexiglass Window Insert Question
« Reply #1 on: August 11, 2016, 10:33:06 PM »

1.Most of the time windows and doors are the weakest point in the system based on mass.
2.no standard acrylic size is 48" x 96" but due to the large size of your window and low frequency traffic noise is the problem I would recommend 3/8" if is affordable. Look at windows like a speaker, flexible in the middle and rigid around the perimeter.. the bigger the window the bigger the speaker.
3. to test the system you must be able to create the air tight dead air space, the bigger the gap between the existing window and the acrylic panel is what dictates maximum value..greater the gap greater the reduction.

not sure what you can do to test seal short of installing window mullions around perimeter.

Randy S.
Randy Sieg

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Mike-Del

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Re: Plexiglass Window Insert Question
« Reply #2 on: August 29, 2016, 05:00:06 PM »

Hi Randy,

Thanks for your help. I have installed the mageseal window system with 3/8" plexiglass. The combination worked pretty good at reducing the tire noise for the traffic. However, the low frequency engine noise still go through especially when diesel trucks accelerate. I'm thinking that the next step would be adding an extra layer of dry wall with Green Glue. Can I just add it on top of my existing interior dry wall? Or should I tear up the existing dry wall first and install RS clip before installing glue green and additional dry wall? Or should I take off the exterior dry wall and install RS clip and green glue at the exterior side (facing the source). Thanks in advance for your response.

Randy S

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Re: Plexiglass Window Insert Question
« Reply #3 on: August 29, 2016, 05:08:46 PM »

is the cavity insulated or hollow?
Randy Sieg

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Mike-Del

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Re: Plexiglass Window Insert Question
« Reply #4 on: August 29, 2016, 05:15:20 PM »

You mean the existing wall cavity? I just moved into this house and not quite sure how good (or if there's any) insulation material in the cavity. By knocking on the wall, I do feel it's relatively hollow.

I have also talked to a insulation guy and he told me that by blow in cellulose as insulation, it can reduce sound by roughly half. I don't really believe his claim based on my own research, but I'm considering doing it if I do go with adding more dry wall.

is the cavity insulated or hollow?

Randy S

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Re: Plexiglass Window Insert Question
« Reply #5 on: August 29, 2016, 05:37:48 PM »

ok first off, do not buy into their statement...yes a hollow cavity is not good but no way would you reduce the sound by half..
Mass law is set in stone, just to see a 5db drop you have to double the weight of the wall.
The only way to gain more is to use clip and channel and create the complex structure but you still have to load mass afterwards.

is the window still the perceivable weak spot? or does it seem all around?
Randy Sieg

Super Soundproofing Co
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888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Randy S

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Re: Plexiglass Window Insert Question
« Reply #6 on: August 29, 2016, 05:54:47 PM »

feel free to call me direct.

Randy S.
760-752-3030
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Mike-Del

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Re: Plexiglass Window Insert Question
« Reply #7 on: August 29, 2016, 06:30:29 PM »

Thanks, Randy. What you said is in-line with what I read from various places. I think right now, the low frequency noise goes through the wall, when it is the worst, I can put my hand on the wall and feel the very slight vibration (I don't expect the completely block this level of noise).

Between just GreenGlue+DryWall and the more complex solution (clip and channel +green glue +extra dry wall), from your experience, how much difference does it make? I think I would be happy if my low frequency noise can be reduced by half with just green glue and dry wall, and if the more complex solution would introduce another half reduction (so total of 75% reduction), I would consider talking to a contractor to scope out the project cost difference. Is my expectation kinda of realistic? (I have seen a lot of good reviews about green glue, but have also seen disappointed reviews as well).

Again, thanks a lot for your time and advice.


ok first off, do not buy into their statement...yes a hollow cavity is not good but no way would you reduce the sound by half..
Mass law is set in stone, just to see a 5db drop you have to double the weight of the wall.
The only way to gain more is to use clip and channel and create the complex structure but you still have to load mass afterwards.

is the window still the perceivable weak spot? or does it seem all around?

Randy S

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Re: Plexiglass Window Insert Question
« Reply #8 on: August 29, 2016, 06:45:07 PM »

Green glue is a great product and I use it in almost every project but what it does is change the way drywall reacts to vibration...like putting your hand on a speaker while it is playing...you can still hear the speaker just the cone is not moving the same way. so another layer of drywall and green glue I would say maybe 20% reduction..if you are looking for 50% for low frequency you will need to decouple and create the complex structure an at least double the mass.

Randy S.


Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Mike-Del

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Re: Plexiglass Window Insert Question
« Reply #9 on: August 30, 2016, 04:27:41 AM »

Thanks for the reply, Randy. The 25% number makes me lean towards tearing down the interior dry wall and re-do it with sound clip + hat channel +green glued additional drywall. I have read quite a bit from Green glue website, but not sure if its necessary to have the double drywall facing the source, which I image would significantly increase my cost. Do you think the same result can be achieved with only the interior wall modification?.

Randy S

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Re: Plexiglass Window Insert Question
« Reply #10 on: August 30, 2016, 03:13:40 PM »

your going to have a "Flank" no matter what on a single wall build. what you do is add the second layer of rock in between the stud when the wall is open. Insulate then add a layer of mass loaded vinyl,  our clips "kinetics" followed by double rock with green glue.

Randy S.

Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Mike-Del

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Re: Plexiglass Window Insert Question
« Reply #11 on: September 14, 2016, 05:14:45 PM »

Hi Randy,

Thanks a lot for your suggestions. I am now in the process of talking to drywall guys about replacing the drywall with clip and hat channels and green glue. I do still have couple questions:

1.  Clip and hat channels make the interior drywall decoupled from the stub, in a sense, the drywall is floating, if that's the case, would I still be able to put furniture against the dry wall? How stable the final wall would be, if one push against the drywall, would the wall move. I do have kid in the house, so would hate to see something that's not stable...


2. I read from somewhere that "decoupling" if done incorrectly may actually hurt the low frequency sound reduction. The guy didnt get into the detailed reasonings. Have you heard about this kinda examples? If there're big not-to-do, I want to communicate that to my drywall guy beforehand.

Also, I have confirmed that the current exterior wall is not insulated. Bad news, but also good since I may be starting from a low point to get more perceived improvement :)

Thanks again.

Mike


your going to have a "Flank" no matter what on a single wall build. what you do is add the second layer of rock in between the stud when the wall is open. Insulate then add a layer of mass loaded vinyl,  our clips "kinetics" followed by double rock with green glue.

Randy S.

Randy S

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Re: Plexiglass Window Insert Question
« Reply #12 on: September 14, 2016, 05:31:15 PM »

Mike,

To answer your questions, with clip and channel the wall will be stable and not move so you would have no worries there. We use UL design methods for clip and channel layout.
If the installation is not done correctly, yes the wall will not perform to full potential and yes it would only take one mistake to cause this to happen.
Look at floating "decoupling" like electrical, if the circuit is open we have no problems..if the circuit is closed its all over.
We will be able to provide instructions for proper install and will be here to answer any questions during the time of installation.

Since the cavity is hollow you will have to start from scratch.

Randy S.
760-752-3030
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Mike-Del

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Re: Plexiglass Window Insert Question
« Reply #13 on: September 22, 2016, 12:53:06 AM »

Hi Randy,

Thanks a lot for your reply regarding my wall modification for traffic noise reduction (mostly low frequency engine noise). The reason I thought RC doest help with low frequency noise was based on the reading from Green Glue's website. I think the theory is with decoupling, the mass on each side is less and resonance happens at around 70hz which makes the performance around that frequency worse.
http://www.greengluecompany.com/sites/default/files/Green_Glue_Vs_Resilient_Channel_1.pdf

Would the approach with RC+GreenGlue+additional drywall move the resonance to lower frequency?? Or it's mainly the damping? If it's the damping, would just addition two additional drywall with green glue provide more damping, and it should still be much easier than RC+GreenGlue+additional drywall.

Sorry for having lots of questions, just trying to get as much information as possible before I kick off the project, as I do want to make it right.

Randy S

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Re: Plexiglass Window Insert Question
« Reply #14 on: September 22, 2016, 06:23:28 PM »

Rc channel is a lower form of decoupling, clip and channel or double wall are far better in the low end.
Green glue is a dampener and changes the way drywall reacts to vibration.
So getting better reductions on the low end would absolutely need a better form of decoupling along with increased mass on the decoupled system..the dampener is the bonus.
but in the end the amount of mass you load on the decoupled system is what gets you the low end reduction.

Randy S.

Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040