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Soundproofing Windows and Doors / Re: Sound proofing condo near airport
« Last post by Randy S on June 20, 2018, 04:46:26 PM »
I see what your trying to attempt, this is the same issue we deal with in commercial store fronts.

Best to use 1 piece of acrylic and not try the mount to the aluminum frame..this will also give you a larger air gap and achieve a better reduction.

if you chose to go your route you will either have to screw into the aluminum or glue the frame to it..

Randy S.
Soundproofing Windows and Doors / Re: Sound proofing condo near airport
« Last post by jakew on June 20, 2018, 04:20:52 PM »
Thank you Randy for your reply.
I don't plan to leave blinds inside the gap. If anything I may uninstall the blinds and reinstall it further away but that is too complicated for now.
As for the double pane issue, since I have a vertical aluminum bar in the middle, I plan to use that bar to install separate vertical mounting frames on the left (for the left pane) and on the right (for the right pane.) That would leave the middle aluminum bar uncovered by either pane. But the glasses will all be covered with no air leak. Would you think that the middle bar could become a weak point? (aluminum is not great in blocking sound I guess?)

STC 37-40 sounds great. I do want to use a more precise sound meter in the future to compare results. But if I can further reduce the 55db jet sound down to 40-45 that would be great. The noise is mainly jet cutting through air, so higher frequency I guess.
Soundproofing Windows and Doors / Re: Sound proofing condo near airport
« Last post by Randy S on June 20, 2018, 03:55:51 PM »
Ok a few things.

1) we never recommend having blinds in the dead air space, this is where heat builds up and can deform your blinds. We have no liability if this happens.
2) the problem of split panels has been a huge challenge that we have not been able to solve without having to add a 2"x4" in the middle to accommodate the mounting frame and maintain the seal and mass behind the gap...other methods we have tried normally become a weak spot or leak and greatly effects the end results.
3) as for mass vs. gap , this one is not so easy. Normally I find in field results the gap is the greatest contributor until you get into really low frequencies and increasing both ends up being the only solution based on cost vs reduction.   

In the end you must be able to create a air tight system and mass on both sides of that air space.

Based on 1" gap you should be able to achieve around STC 37-40 with 3/8" acrylic.

Hope this helps and if you decide to attempt an out of the box method please share it with our readers on this forum and let us know the results.

Good Luck.

Randy S.
Soundproofing Windows and Doors / Sound proofing condo near airport
« Last post by jakew on June 20, 2018, 06:42:34 AM »

I recently moved into a new condo near an airport. Condo faces east, and jets also go east on a 1000-2000 feet height. Noise is pretty annoying (when in door, going from 40db when quiet up to 55 db, on my phone app but that may not be very accurate. In the outside my phone measures ~75db so my current window does a ~20db reduction on my phone).

The condo is already installed with double-pane window. There are 3 room facing east, and each one has a big window. Attached picture is one bedroom for which I want to try the acrylic solutions (along with the supplies) and see what kind of difference it makes, before deciding on what to do with the other two rooms. This bedroom window is 58x49 inch.

I would not want to use a single heavy panel that blocks the entire window because I do want the window opening to be operable in times of need. So I was thinking to use two 3/8 panel, one covering the left part (including the opening, 58x22 overall) for easier removal, the other covering the right part (sort of permanent). As shown in the measurement picture, if I attach a panel on the middle aluminum slash, the best gap I get is around 1.3 inch. If the result is not satisfactory, I would consider attaching another whole panel of 1/8 thickness on top of that, because as you can see in the picture I do get another ~0.9 inch space to attach to a top piece of slash before it runs into the blinds. 1/8 thickness would be easier to remove.

Does this sounds too complicated or a bad plan? Is this possible without drilling holes in the frame? That is a last resort but I'm willing to try something else that does not leave holes if possible.

My situation is very similar to these two guys I think,4069.0.html,4176.0.html
if you get a chance to add 2 more layers make the first layer cement board like 1/2" hardie backer 3lbs sqft. or 5/8" perma base 3.6 lbs sqft., not durock 2.6lbs sqft..

Randy S.
Thanks a lot for the extra information. Looks like I would need at least another 2 sheets of drywall. If I suggest that to the wife she would probably kill me so I'll just have to live with what we have.  :)

Thanks again.
That is correct, unfortunately this is normal.
Standard 5/8" drywall weighs 2.3lbs sqft you have 1/2" OSB 1.7 lbs sqft on the other side plus what ever the siding weight is. = 4 lbs sqft.

you added Silent FX is 2.8 lbs sqft. you did not double the mass.

now, doubling the mass does not always give you desired results depending on the source, most projects I find myself at a minimum 8-9 lbs sqft just for low performing systems.
satisfactory systems are 10-12lbs sqft.

Now any bass or impact will still be able to come through unobstructed due to the single frame construction.

Randy S.

Thanks for your reply but I'm not sure I follow. I found this

"The most important law in soundproofing is the mass law.The mass law equation says that each time the mass per unit area of a single layer wall is doubled, the transmission loss is increased by about 6 dB."

By adding the second layer of drywall, wouldn't I have been applying the "Mass Law"?

you did not follow Mass Law, and this is why you are not seeing the reduction you anticipated.

The other potential issue is that you do not have complex structure and therefore are stuck in Mass Law.

Give me a call direct and I will be happy to thoroughly explain this so you do not make another mistake.

Randy S.

I'm trying to understand why all my efforts to soundproof a wall in our bedroom keep failing.

Here's the situation; Our north wall is 46ft long, 1 and half stories high (half the lower level is in the ground), no windows or doors. All our bedrooms and bathrooms run along the wall. Directly on the other side of this wall is our neighbors deck (about 5-6 feet away). When they're on the deck talking and yelling, we can hear them... all night

Originally, this wall had 5/8 drywall, 2x6 framing, fiberglass insulation, 1/2 osb, 1.5in Styrofoam, vinyl siding.

To start fixing this, I simply added a layer of 5/8 CertainTeed SilentFX drywall in our bedroom. The claim from them is that it "features a viscoelastic polymer between two specially formulated dense gypsum cores significantly improves sound attenuation and is ideal for systems requiring high STC performance." It was super heavy stuff. I installed it over the existing drywall with a gap all around the edges which I filled with acoustic sealant. This helped a little but we can still hear the neighbors talking and yelling.

I found out that the OSB  on this wall had a lot of rot due to the Styrofoam not being sealed. My thought was that the rotten OSB (lack of mass), was letting a lot of noise through, like an open door. Also, it seemed to me that Styrofoam can amplify sound (I can share some youtube video's to show what I mean). I tore down the outside of this wall, replaced all the OSB, sealed all cracks and gaps, then replaced the Styrofoam with Rockwool Comfortboard 80 (suppose to absorb sound). After doing all this... there was NO change in the amount of noise coming in. I was totally shocked.

Am I cursed? Or is there something else I've missed? Based on the STC rating of the drywall alone, I shouldn't be able to hear anyone talking normally. Yelling should be murmurs.
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