Making SUPER Soundproofing Plugs for Windows.

Obviously, you deserve relief from outside noises!  Whether it is sleeping or just enjoying quiet, windows are one of the most common entries of noise into or out of a room.  Glass and wood framed windows seem to be almost invisible to sound.

An  alternative to replacing the existing window with a double or triple pane glass acoustical window,  (a noise reduction of about 30%-70%), or to add another interior window, (90%) is to make a removable soundproofing “plug” to fill the frame and to block the sound coming through the window. (Also 90%)  While this will also block light, it won’t matter if the window is a bedroom and  noise is keeping you from using your room or sleeping.  If light is wanted for day use, make the plug removable. It can then be removed to allow light to enter the room.

Making the “Plug”.

Measure your window frame to see how much depth there is to the sill. This will determine the thickness of the (Super Soundproofing Mat), you can use.  If your frame depth is 4″ a thickness of 2″ is recommended.  The dead air space will work for you.  Leave a dead air space if possible, the foam should not be pressed against the window.  The soundproofing mat is cut from rolls that are 4′ wide and is sold by the running (linear), foot. So if your window was 4′X4″, you’d need 4 running feet of it. If you window is an odd size, like 4′X4’5″, order the next largest foot size: 4′X5″  If an odd size ( Like 6.25′X5.75″)  you’ll need to piece it together.

Usually, one thickness of 2″ “Super Soundproofing Mat” will do.  This thicker mat is relatively stiff, but windows over about 4′X4′ may need a “backing board”.  This is simply some lightweight wood or fiber board to attach (glue) the mat to.  (Luaan, very lightweight and cheap, is one type to ask for at the hardware store).  For an even better soundproofing effect, use “Homasote” or other fibrous board.  “MDF” (Medium Density Fiberboard), is also recommended but is quite heavy.  Don’t use particle board or plywood.  Use contact cement to cement the mat onto the backing board.  (We have some with a peel off backing). Cut a few holes in the back for your fingers to fit while handling the plug, if planning to remove it on a regular basis. The backing board should be large enough to go over and cover the inside frame molding right over and to it’s edges.

The plug should fit the window opening very securely without gaps which could allow  sound to enter. It probably doesn’t matter much  which way it is inserted, but if you place the soundproofing on one side of the board, you could add another layer of soundproofing mat to the room side of the backing board for even more sound reduction, if needed later.  Make sure the mat is cut an inch or so oversize to make it fit tightly into the frame to help block the sound that may come through the edges of the plug right at the window frame.

An added bonus of such a soundproofing plug is the thermal insulation property of the window goes way up, keeping you warmer in winter and cooler in summer! A 1″ layer of our Super Sound Proofing Mat” alone is about R-5.5 so it wouldn’t take too many layers to equal a very high “R” number. (The R number refers to the insulation quality of a material).

If the window is exposed to full sunlight all day, it may be prudent to help limit heat buildup between the glass and the soundproofing mat by first lining the window with aluminum foil as a reflector.  The mat can withstand temperatures of over 200*F so don’t worry about it!

If a plug as described accomplishes the purpose, or if the window is very large, it may make  sense to leave part or all of it in place rather than to make it removable. In that case it can be sealed by caulking it around the edges, which will help the soundproofing effect. Add a string to the caulked in seam to facilitate later removal as in an emergency.  More layers of mat can be added to the backing board on the room side if needed.

If large amounts of sound are being passed by a window, either way, (in or out),  more drastic measures may be needed. This could entail lining your window with a limpid material to give it more mass, such as our “mass loaded vinyl” (mlv)  we call “flooring”.

We  have the mat in up to 2″ thicknesses  and it is plenty firm enough to  push into place inside the window frame if the window is not over about 4′X4″ in size  and you cut it a bit oversize of the opening.   A dab of cement like household “Goop” or even “Duct” tape will hold the mat in place if needed.  Caulking the edges is better.  The mat is made of a vinyl material which may, if brand new,  have a “shower curtain” odor when first opened.  This is harmless and will quickly go away.

Remember, somewhat of a dead air spacing between glass and the plug is needed for best reduction of sound in a  framed window  so don’t push it in all the way up against the glass.

Sometimes a heavy curtain or drape will help to additionally reduce loud sound to a more tolerable level.

You might also consider adding a shutter (Noise Barrier), to the outside of the window if it’s practical.   3/8″ clear acrylic plastic,  will even work, but must fit well!  (Use caulk!).

If you need light, use our clear plastic curtain material or better the MagnaSeal system.

If you decide you’d like to get a interior window, you have some choices.  On the West coast go to  here!    Or do it yourself:  “Poor Man’s Interior Window”

Go to Robbys   Apartment or  the  Basement 
Foam Mat.

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