I am going to be creating my first soundproof door assembly. I have my idea down for the frame and door itself, but the problem is going to be that empty space between the door assembly and framing of the wall.

A few ideas I've had:

  • Get some MLV (mass-loaded vinyl) and backer rods. Wrap the backer rods with MLV and stuff them into the cavity. The rod will allow for compression which would give a tight fit.
  • Sand. This may sound insane, but I figure I could create a custom casing that I could slide into the cavity, after which I would pour sand into it from the top. The casing would eventually fill up and expand to fill the cavity. The only thing I might have to worry about is settling which would require it to be refilled a bit at the top, but perhaps there's a type of heavy sand that wouldn't settle.
  • Green Glue. Using my MLV/backer rod method, an idea came to me to create an actual sheet of Green Glue which would serve the purpose of the MLV. Basically, I would get some heavy-duty plastic, spread GG liberally out all over it, then put another layer of plastic over the top. If I gage the thickness with something that's about 1/8" like some thin dowel rods running along the length of the inside and then setting something heavy on top to flatten it out and disperse the glue, I think I can get a consistently level sheet of GG compound. GG thickens up after a few days, so I wouldn't have to worry too much about any of it squishing out all over the place.
  • Safe 'n Sound insulation stuffed liberally into cavity.

Since my door is going to consist of a layer of plywood, GG, cement board, GG, and plywood all in that order, I am sure it's going to have a fairly high STC. Therefore, I'd like to make sure I get the edges around the door really well even if it means the edge has an aburdly high STC in comparison to the wall and door assembly themselves.

  • By door assembly do you mean the door jamb? Nov 16, 2012 at 15:06
  • Why not use spray foam? Nov 16, 2012 at 15:09
  • Greebo, jamb is what I was referring to. Chris, I've never known spray foam to have properties designed specifically for sound deadening (even though using spray foam is technically better than having an open gap). Nov 16, 2012 at 15:18
  • @ChrisCudmore be careful with spray foam around door and window frames. You need to only use the type that doesn't expand, otherwise it will bulge out the frame and prevent the door or window from working.
    – BMitch
    Nov 16, 2012 at 16:58

2 Answers 2


Noiseproofing, as you know, is best assisted by decoupling dense masses.

I am going to presume that your walls are framed thicker than standard 2x4 (as staggered 6 is a very common technique)

In this case, you have a pretty wide cap to fill in the shimmed jamb.

I would shove fiberglass into the cavity, or spray in foam, making sure not to overfill!

Then I would lay in greenglue (or their gap-filling material), then I would lay in the backer rod. Finally, one more application of the gap-filling material before setting the casing.

Here is a video of a door company demonstrating the install: http://www.acousticalsurfaces.com/acoustic_doors/soundproof_doors.htm

  • I didn't even think about acoustic caulk (aka gap-filling material). I have a ton of QuietSeal left over. Stuffing in a length of backer rod into the gap then caulking it would work real, especially if I do the same on both sides. On the sides, there's probably a 1/2"-3/4" gap. It's about 1 1/2" at the top, though, and that could be more of a problem. Nov 16, 2012 at 19:05
  • For the large gap at the top, pack with rigid acoustic foam and seal gaps as needed.
    – Matthew
    Nov 16, 2012 at 19:58
  • Actually, since I am making my own door and frame, I will just add a little extra height to it so that there's only 1/2" gap at the top. I believe I am going to go the caulk route. Good link, too. Nov 17, 2012 at 0:28

I used to work at one of the large hardware chain stores, and we would recommend to people to stuff an ample amount of R-11 or R-13 fiberglass insulation in there. If you've got more space, you could look at using strips of fiber board, (or concrete expansion strips), or specially designed sound-board (also available from most large hardware stores).

  • 1
    By "stuffing" it's important that insulation doesn't become compressed for thermal insulation. Safe 'n Sound may be the best material for this purpose.
    – BMitch
    Nov 16, 2012 at 16:57

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