Not quite sure what to do here...?

I'm using whisper clips with hat track and two layers of sheetrock with GG in between to soundproof a ceiling in a basement room. The room has two windows. I'm not worried at all about sound escaping through the windows to the outside - there are no houses anywhere near us. My only concern is in blocking noise from going up through the floor of the room above. When I combine the height of the clips, hat track and sheet rock, my ceiling will end up being at the exact level of the inside of the top of the windows. I plan on sealing the joint with sound caulk. My fear is that noise will leak up through the window frame, which is plastic. The frame itself is isolated from the rafters, so there is no direct connection there, but the thin plastic doesn't have much mass. I've got 1 1/2" between the top of the window frame and the rafters above. Any ideas on how I can prevent noise from leaking through the frame? I was thinking of just laying 2 layers of sheet rock with GG over the top of the frame, but I'm not sure if that will do any good... :?:

If sound gets out through that glass (and it will), then there is no question that it will be heard upstairs, no matter what you do to the ceiling, or how well you seal the frame. That is just thin glass in there: sound will get out pretty well. What kind of isolation are you trying to achieve? - Stuart -

Soundman2020 wrote:

If sound gets out through that glass (and it will), then there is no question that it will be heard upstairs, no matter what you do to the ceiling, or how well you seal the frame. That is just thin glass in there: sound will get out pretty well. What kind of isolation are you trying to achieve? - Stuart -

Thanks, again I don't care if sound goes out through the glass to the outside, I am just trying to add some mass to the top of the plastic window frame so it has roughly the same sound proofing level as my double sheetrock with green glue ceiling.

Once again, it looks like you missed the point. You are wasting a huge amount of money by putting all that sheetrock and green glue on the CEILING, when sound can simply flank AROUND it, out through the window... Think about it a little bit: Low frequency sound is not directional: it will get out through that glass EASILY, it will wrap around the entire house, and it will get back in again through another window, a door, the walls, the roof, etc. You cannot stop sound by only treating one wall of a room, any more than you can build an aquarium by putting glass in only one side of it... In other words, unless you do ALL the walls of your room, you will not succeed in stopping sound from getting up into the room above.

The room has two windows. I'm not worried at all about sound escaping through the windows to the outside ... My only concern is in blocking noise from going up through the floor of the room above.

The floor is not the point. The floor is only PART of the issue. The windows and walls are the rest of the issue. No matter how good you make the ceiling, it WILL NOT DO WHAT YOU WANT. Sound will get around it ("flank") through any number of other paths that you say you "are not worried about", but in fact you should be very worried about. Once again: What are you trying to achieve? (in terms of numbers). How loud are you? How quite do you want to be? - Stuart -

Stuart is right

I'm sure he is, but I have somewhat limited options and would prefer to at least try my plan to see how much sound is leaking through the glass and if I can live with it. There is a lot of benefit to getting natural light and the ability to get fresh air in as well. This is a practice / jam room for electric guitar playing. I don't know what numbers I need, but it is certainly not equivalent to a loud band. I can always add a sheetrock/GG/sheetrock layer over the windows if I need to once the walls are finished. It won't look that great, but once taped and painted won't be hideous either. So my plan is to fill the top cavities of the window plastic with caulk to give it some mass, then attach a sheetrock/GG/sheetrock layer over the top of it as best I can - probably screwing it right down into the cement on either end.

Perhaps run the ceiling drywall to the foundation and seal to foundation to at least put a lid on the room. You'll have to drop the ceiling with a resilient mount to get it low enough to intersect the foundation.

Randy K wrote:

I'm sure he is, but I have somewhat limited options and would prefer to at least try my plan to see how much sound is leaking through the glass and if I can live with it. There is a lot of benefit to getting natural light and the ability to get fresh air in as well. This is a practice / jam room for electric guitar playing. I don't know what numbers I need, but it is certainly not equivalent to a loud band. I can always add a sheetrock/GG/sheetrock layer over the windows if I need to once the walls are finished. It won't look that great, but once taped and painted won't be hideous either. So my plan is to fill the top cavities of the window plastic with caulk to give it some mass, then attach a sheetrock/GG/sheetrock layer over the top of it as best I can - probably screwing it right down into the cement on either end.

Get ye some laminate glass and replace the existing glass in that window. The issue is air-borne not so much flanking once you decouple the ceiling since the window is basically a hole in the wall. Once sound gets out of that hole it acts pretty much the same way a monitor baffle does, sound spreads like pouring rain on the wall taking the path of least resistance. Things that can make your situation better are that the openings in this exterior wall be far away from the original window currently in question. Take it for what it's worth, or what it cost you ;) Brien

Thanks for the advice guys. I'm also looking into building a window plug which I saw detailed on another site - a removable block that will fit snugly in the window frame with seals. Might be the perfect solution for me.

Take care, since fitting "in the window" means you have not covered the likely gap between the drywall and the window jamb. This may be hidden under the casing. You may need to build a plug that fits over the entire window, including the casing and gap. Always cover your gap :lol: