Monday, February 6, 2012

Soundproofing Windows with Homemade Plugs

Window's are always going to be a real weak spot when trying to soundproof a room.  While we did a lot to soundproof the new space (blog on that here) and it's working out great, I really wanted to make sure that the loud guitar amps and drums bleed out to the outside as little as possible.

To that end I decided to make some window plugs out of some of the left overs from the reno.  I took some drywall pieces and sandwiched a bottle of green glue in-between them and then I screwed some wood on either side to fasten the pieces better.  To create an airtight seal I got some Green Glue Company floor joist tape and I wrapped it around the plug a few times. The tape stuck great to the drywall but not to itself so I shaved off any excess and used tuck tape to make sure it was held nicely in place.

First we gotta apply some green glue soundproofing compound to a cut of drywall:

I put the two pieces of drywall together and screwed them between some wood so they would stay together better.  After that I wrapped around some Green Glue company joist tape so there's a soft, flexible material around the sides.  This makes a better seal and helps prevent damage to the window well.

I cut the excess joist tape off the sides of the window plug and then fasten it better with Tuct tape.

So now what I have is a pretty ugly window plug, haha.  I bought some speaker carpet and carpet glue to fix that.

Last step is adding some handles so it's easier to get it in or out.

If you read the soundproofing blog you'll know that this window is pretty hardcore but no soundproofing is perfect and in certain instances I want even more soundproofing.  If you're interested in window boxes with multiple panes of glass check out the soundproofing blog


The thing that is really great about this is that you could soundproof a window without causing any damage to the window or well.  This is a great plus if you're renting or aren't in a position to do anything more permanent at your location.


I used an iphone db meter app (one of the ones which had a good review) and tested the sound with and without the window plug.  Here's the results:

Sound level in middle of room:              95db
Sound level outside by the window:      56db
Sound level outside window /w plug:    47db

It should be noted that 47db was about the residual noise in the neighbourhood because that's the level I had outside without any music playing at all.  To give you an idea of a relative measurement a small car driving past gave me a reading of 69db.

Anecdotally the sound coming out of the house was noticeably quieter with the plug installed in the window.  If I get a chance I'll retest with a more professional db meter if the opportunity arises.

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  1. Really clever contraption Ashton! I've seen tutorials for diy acoustic panels, but this the first I've come across for windows. Thanks for the tip.

  2. I'd be interested in a measurement of the difference the plug makes to the level of sound coming *into* the room from outside. Thanks.

  3. Thanks Jeff!

    Paul: The results would be the same whether the sound is stopped going in or going out. Thanks for your interest!

  4. How much smaller did you cut the drywall than the window frame?

    Thanks very much for sharing- I'm about to build some myself and this is super helpful.

  5. great tips. I am a day sleeper and I needed this for a very long time. thank you for sharing!

  6. Thanks a lot for sharing your numbers/tests. I am about to do something similar in my bedroom windows and these were the data I was looking for!

  7. This is exactly the kind of removable window plug I need to satisfactorily augment the attenuation of outside noises I've already achieved by treating the one window in my bedroom. Ideally, the removable plug would cost me a lot less than to have someone locally install one ~ 40 lb thick decorative drape permanently installed on a sliding track jutting out 3" from the wall.

    The window frame is ~ 48" x 64" wide and the casement window is set inside of it at a ~ 3.5" depth. Each of the two windows opens with a removable crank. My brother in-law kindly did an excellent job of tightly taping black trash bags over the windows. This gives me total black out while sleeping and I was amazed at how much it blocks exterior noise. And there are pull string plastic vertical blinds which I normally keep closed which add a bit more noise reduction. But I'm still looking for perhaps another 20db attenuation. Naturally, this bedroom windows needs to be fully cranked open at least once a week for aeration and for UV ray blasting to kill any airborne mold. So I need the plug to be removable like yours here.

    But I don't have enough skills and the time to build it myself. Anyone you could recommend who I could pay locally who would work from these plans? I'm in the 11724 zip code, 631 area code.