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4.5
The main point you need to know is that GG and an extra layer of drywall can help...but don't expect anything too dramatic from just that. My problem was noise coming from a downstairs bedroom (darn kids!) going through the ceiling and into the master bedroom. So, I went all in:1. Rip out the existing drywall ceiling. This isn't terribly hard; cut the drywall tape along the corners with a utility knife, then start a hole somewhere with a drywall saw (or hammer if you feel like it) and start pulling sections down.2. Screw strips of drywall to the underside of the exposed upstairs floor with a layer of GG in between. Building codes aside, I would suggest using as few screws as needed to solidly secure the panels. For ALL new drywall, use the heavier 5/8" sheets; mass is your friend. The floor will be normally be about 3/4" thick, so 1.25" drywall screws will work nicely for the first layer.3. Add a second layer of GG'd strips of drywall to the underside of the floor. If you have the patience and ambition, run a bead of acoustic sealant around the edges (so none of the floor is exposed.) At this point you have two layers of drywall and two layers of GG clinging to the underside of the floor. For this layer, you'll need longer screws to reach the floor (such as 1.75")4. Attach whisperclips (or other sound isolation clips) to the bottoms of the trusses or floor beams (to provide support for the new ceiling.) This will take some thought, taking into account that the furring channel (25 gauge, 7/8") should be placed two feet apart, with clips at the ends and every four feet in between. You'll also want to carefully position one of the steel channels where there will be a joint between sheets of drywall (so both sheets can be screwed onto it.)5. Clip furring channel into the clips. I found it easiest to mark where I wanted the ends to be, screw those clips into place, then clip in the channel, and then add any additional clips. (The channel is flexible enough that you can pull it down enough to slip more clips on it.) A common frustration is where to get these steel channels; I found them at a regional home supply store (Menards), or some Home Depot stores carry them. You may have to mail-order them in the end. RESILIENT CHANNEL is NOT an alternative! (This is the stuff that has holes cut in it. You want the solid stuff for use with clips.)6. Install a layer of insulation. You actually want open insulation (such as the cheap fiberglass rolls) rather than closed-cell foam. I went with thick R-19 faced rolls.7. Screw the first layer of 5/8" drywall to the furring channel. Your 1.25" drywall screws will work for this. To hold the sheets of (fairly heavy) drywall in place while you work on them, you'll either want to rent a panel lift or have a couple of strapping young lads to take advantage of. ;-)8. Seal the edges and any gaps with acoustic sealant.9. Time for more GG! Now, the second layer of 5/8" sheetrock goes up! Goop up the backside of a sheet with a random pattern of GG, using around two tubes per 4'x8' sheet. If you wish you can increase the dose to about three tubes for a small additional gain in damping. The GG is fairly watery, and dispenses quite quickly and easily. These are the 'big' tubes; you'll need a large caulk gun (not the smaller size often used for caulking in bathrooms, etc.) Repeat until the entire second layer of drywall is up (with a layer of GG in between the layers.)10. Seal significant gaps with acoustic sealant or expanding foam or such. Finish and texture as you normally would with drywall.Did it work? YES! Before, even normal conversational voices could often be heard between upstairs and downstairs bedrooms. Now, even with music at a 'high normal' volume (ie. about as loud as a sane person would want to listen to music for an extended period at) it remains dead silent in the other room. It was a lot of work (and all told, materials and tool costs ran close to a thousand dollars for about 170 sf of ceiling/floor) but I'm very pleased with the results! Now, it's hardly an absolute barrier to sound; loud noises (like somebody really rocking out with their stereo or loud yelling) can still penetrate. But normal noise is no more!A few closing thoughts...GG cures very slowly. It can still be tacky several weeks after being dispensed, so it's not surprising that it doesn't take full effect for weeks. It does generally easily wash clean with water, although if a film of it dries on your hands it can be hard to completely get rid of the tackiness. The smell is very mild and inoffensive.If you have ductwork running through the ceiling, consider making some soundproofing efforts there as well (such as by wrapping it with an adhesive mass loaded vinyl type product.) If there is a duct feeding into the room through the ceiling, the gap between it and the new ceiling can easily be filled with expanding foam insulation, and the grill simply screwed onto the new drywall.Light fixtures will need some consideration. Surface mounted fixtures can be easily removed; after feeding the wires through holes in the new ceiling, seal up any gaps with expanding foam or acoustic sealant. The light fixture itself can be secured to the ceiling with anchors and bolts (look around your local home store.)If you have recessed lighting, they need special attention; search for how to assemble a box around them to prevent sound transmission through the fixture.Good luck! It's not a small project, but if peace and quiet is important to you, there is definitely hope!
