Champagne taste beer budget Posted August 3, 2004 Share Posted August 3, 2004 I realize, in a perfect world, there would be nothing but open floor joists above a listening room that could be stuffed with insulation to help cancel noise transmission. However, I'm building a house in the real world, and it looks like a pile of spaghetti that got dropped on the floor, what with air ducts, air exchanger pipes and what have you running through the joists. Sould a person just stuff it as full as possible, into every nook and crannie that you can, or is there a better way? I want to try and maintain the loft of the insulation, but some of the spaces are going to be tight and will have to be stuffed using a stick or something to get the insulation into the nether regions. Any suggestions? Quote Link to comment Share on other sites More sharing options...
dougdrake Posted August 3, 2004 Share Posted August 3, 2004 From the little reading I've done on this over at www.avsforum.com, it seems that insulation provides little help in keeping noises from travelling out of a room. They seem to say that nothing really stops noise except thick, solid walls/ceilings and isolation of those walls/ceilings from the rest of the house. Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted August 3, 2004 Author Share Posted August 3, 2004 I'm already planning on a double layer of sheetrock on all the walls and the ceiling. Maybe I should have used a different term than insulation. I might end up lining the inside with Roxul, OC 703, or some similar material. I realize standard pink insulation isn't made for acoustical purposes, but seems to me someone on here said it would help improve the absorbtion inside a wall. Just looking for ideas, and figured this would be the place to ask. Quote Link to comment Share on other sites More sharing options...
artto Posted August 3, 2004 Share Posted August 3, 2004 Regular unfaced fiberglass insulation will help reduce any resonances in the cavities between the joists and studs. As such, it does contribute improving the STC rating. Sound getting out of the room is generally not as much of a problem (except at lower frequencies) as sound getting in. Dont forget much of the sound transmission can come from utilities such as water and gas pipes, HVAC ducts, sump pump ejector pipes, etc. If possible, wrap pipes and HVAC ducts with something like aluminum foil backed foam insulation that is used to improve thermal insulation efficiency. Even if you cant get all the way around, it will help damp vibration and resonances. To alleviate mechanical sound transmission, isolate these same utilities from the building structure. I simply used several layers of closed cell foam tape as used for weather striping for the pipes and ducts to rest on. Before putting up drywall on walls and ceilings, I applied a bead of silicone caulking. I also installed a layer of ½ Celotex rigid insulation before putting up the drywall (actually several layers with air spaces on the walls). The laminated sheetrock is a good idea (overlap the joints!). Much of the sound transmission can also come from impact noise, such as walking on the floor above the ceiling. This is best controlled at the source through the use of carpeting. In any case, you might want to consider using a thin (1/8) limp mass high density sound barrier such as Auralex SoundBlok, which is denser than lead. Its expensive, but new construction is the best time to install this stuff. I wish it was available when I built my room. I recently used it under the cement backerboard and new ceramic tile kitchen floor. Even with the harder surface (previously Solarium vinyl sheeting) the impact noise has been substantially reduced. You might even consider using it as a layer between the sheetrock. Thats what I wish I could have done. You should also consider installing additional cross-bracing or 'stringers' between the joists and studs to help stiffen them. The sheetrock, preferably should be glued to the joists and studs, sealing the points of contact with silicon caulking, especially around joints. The final may be screwed down. This makes for fewer penetrations and less mechanical transmission than if you screwed each layer down. Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted August 3, 2004 Author Share Posted August 3, 2004 Why did I know you were going to recommend the Sheetblok? I've checked into it on your recommendation before, and can see it would be the ideal answer, but just to cover the ceiling would be over three rolls, or $1300 +/-. At this point, I'm going to just have to do the best I can with isolating everything with the foam tape, stuffing it with insulation and making the appropriate walls/ceiling configuration with the rigid insulation and several layers of sheetrock. Todays immediate project is getting the antenna put up on the roof and getting the feed ran down the walls before the sheetrockers get there and make things much tougher. The listening room is still a while off, we have a few months of work to do ourselves just to get the upstairs finished. Quote Link to comment Share on other sites More sharing options...
sfogg Posted August 3, 2004 Share Posted August 3, 2004 "I'm already planning on a double layer of sheetrock on all the walls and the ceiling." Put the ceiling drywall on a new set of studs that have no connection to the above floor joists. Shawn Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted August 3, 2004 Author Share Posted August 3, 2004 On 8/3/2004 4:25:09 PM sfogg wrote: Put the ceiling drywall on a new set of studs that have no connection to the above floor joists. Shawn This might sound like a silly question, but how would one span a 18x23 room without connection to the above floor joists? I suppose I could build a set of rafters for the room, then deal with the 4'8" ceiling height at a later time..... Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted August 3, 2004 Author Share Posted August 3, 2004 This is just so sfogg and I will have an equal post count, even if just for a short time. Quote Link to comment Share on other sites More sharing options...
Klipschfoot Posted August 3, 2004 Share Posted August 3, 2004 Are you ready for this? Build a room within a room. No touching framework. Insulate only between the ceiling joists of the floating room and the floor joists of the room above. You will lose about a foot of ceiling space (or more) but you will you will have the ultimate isolated audio room. You can also thicken the slab below the new audio room. Another downfall, you will have to control the heat that will ultimately build up in the downstairs room due to all the insulation. Okay, I was kidding about the slab. This is tantamount to a recording studio but it is the best real-world solution. It only takes extra money and time. Quote Link to comment Share on other sites More sharing options...
sfogg Posted August 3, 2004 Share Posted August 3, 2004 You attach the new studs to the top plates of your side walls. Built them 1/4 or a 1/2" lower then the existing joists. See the pics and some explanation of this from me here: http://forums.klipsch.com/idealbb/view.asp?mode=viewtopic&topicID=50686&num=30&sessionID={7E63FFD2-0BE7-4817-A809-DEAC058C1F1A}&pageNo=7 When your ceiling is built this way it is pretty much irrelevant if you have hardwoods on the floor above you and people walking over it. That link also talks a little about how to build the walls to limit sound transmission through them. If this room is in your basement on poured concrete you can get away without floating your floor. Shawn Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted August 3, 2004 Author Share Posted August 3, 2004 I'm all for the room within a room concept, though at the moment there isn't even a room to start with!! Just a cement slab, two poured cement walls and some hand drawn lines on the floor to represent movement. I mean the walls. LOL. In floor heat, so I can see it's gonna get plenty warm in there! Seriously, how big of a board would you need to use, on edge, to make the ceiling not sag in the center? Remember, this is a 17-18' span the short way. I don't want any support posts in the center of the room. It currently has 8' to the bottom of the floor joists, so if I needed to use 2x12's, with the air gap above and sheetrock on the inside, I could end up with a ceiling height of only 6'10? I'm 6'4 and don't really want to be that cramped, not to mention what that low number could do to the room modes. Above this room everything will be carpeted bedroom or master bath, except for a short section, maybe 5', of 4' wide hardwood floor hallway. Edit: Shawn, I counted out your studs, assuming they are 16" OC, you must have a 13' room? Hopefully artto the architect will chime in on how long of a span can be reasonably covered with a certain board. Quote Link to comment Share on other sites More sharing options...
sfogg Posted August 3, 2004 Share Posted August 3, 2004 "Remember, this is a 17-18' span the short way" How long of a span are your existing floor joists covering? My are around that length with 2x10" and they have to support far more weight then just a drywall ceiling. Remember too you can double up on studs if you wanted to increase their strength. "It currently has 8' to the bottom of the floor joists, so if I needed to use 2x12's, with the air gap above and sheetrock on the inside, I could end up with a ceiling height of only 6'10?" No, you recess the new studs in between the existing studs. I lost maybe 1/2" of headroom building the room this way and I'm 6'4". With the drywall the ceiling is 89" off the floor. The air gap is the space from the drywall to the plywood above... mine is about 10". I did have to rebrace the existing studs though to allow this to work. They had X braces between the studs. I changed to to angle braces basically so the new studs could push up higher between the old studs. " I counted out your studs, assuming they are 16" OC, you must have a 13' room?" Yup, that is just about the width of the room. Shawn Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted August 3, 2004 Author Share Posted August 3, 2004 The light bulb is starting to come on, albeit dimly. It was glowing brightly when you said to recess the new studs into and between the current joists, but it started to flicker when I remembered that there is a lot of HVAC ducting strung in between the current floor joists. Yeah, the current florr joists span nearly 24 feet, but they are also 18" high and have the "X" and "I" pattern ran through them continuosly, not just boards on edge. If I did the ceiling this way, I'd prefer to have sheetrock over the ceiling joists/studs, then insulation, then sheetrock again, which would be impossible with them sticking up into the existing floor joists. Still glowing, but only at abour 3 candlepower. Quote Link to comment Share on other sites More sharing options...
Klipschfoot Posted August 3, 2004 Share Posted August 3, 2004 Champ, I doubt you would get anyone here to spec your home for you. But keep in mind that doubling up on 2x10's and/or using 10"OC will go a long way to support a floorspan of 13 feet. Also, crossblock between joists to avoid any chance of warping. Sagging is not your only enemy. At all costs, overbuild to avoid deflection of the floor. That bounce you feel in a regular home is unacceptable when you learn a few things about quality building. Unfortunately, building only to meet code allows for tolerances that very few homeowners are aware of until they walk across their living room and everything shakes. A dining room where dishes rattle in the china cupboards are common. Most people just accept it. Fixing it is as easy as access to your floor joists. EDIT IN RESPONSE TO POST BELOW: Okay, nevermind about the dimensions. Yea, I got lost in the posts. Glad to hear your floor is solidly built. I lived in apartment for a while where the only place I could put the TT was the outside corner wall. Love that 70's low bidder construction. Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted August 3, 2004 Author Share Posted August 3, 2004 Klipschfoot, me thinks you may have gotten a couple posts jumbled together? SHAWN's room spans 13', mine is 17-18 wide, 23 long. Believe me, in the building process I've been putting a heavy foot down on every quare foot of the upstairs floor, and there is no sagging/squeaks anywhere. They used subfloor glue across the top of every floor joist, nailed everything down tight, I think that part, which I had NO hand in designing, will be fine. Right now, all that will be the listening room is air and the upstairs floor joists above it. Besides the corner of the poured external walls, which are underground on the outside, and the poured cement floor, which I had them make extra thick just for you! (Actually, I'm not really concerned, but a little apprehensive about shooting nails through sole plates down there with the in-floor heat, but have been told to just use a couple nails and good glue, that often the glue is stronger than the nails would be.) Quote Link to comment Share on other sites More sharing options...
sfogg Posted August 3, 2004 Share Posted August 3, 2004 " If I did the ceiling this way, I'd prefer to have sheetrock over the ceiling joists/studs, then insulation, then sheetrock again, which would be impossible with them sticking up into the existing floor joists." Your other option (though it causes debate too) would be to do the new studs like I suggested. Then put up a layer of 5/8" drywall. Then run resileant channel and attach another layer of drywall to that. Typically the dual layer of drywall on the new studs are what is suggested most though. You want as much mass as possible to try to keep the bass from penatrating that layer. The air space and the upstairs floor are the second mass layer. Another option if you wanted to take this route is to have the whole theater designed and specced out by a professional. See: http://www.DesignCinema.com/ For example. Shawn Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted August 4, 2004 Share Posted August 4, 2004 There is a building product called 'resilient channel' I believe, which is a metal 'z' shaped bracket that you screw to the joists, then screw the drywall to the other leg of the 'z', it is supposed to reduce noise transmission. Look for it at your local drywall/acoustical ceiling dealer. Quote Link to comment Share on other sites More sharing options...
artto Posted August 4, 2004 Share Posted August 4, 2004 ---------------- On 8/3/2004 4:25:09 PM sfogg wrote: "I'm already planning on a double layer of sheetrock on all the walls and the ceiling." Put the ceiling drywall on a new set of studs that have no connection to the above floor joists. Shawn ---------------- sfogg, (as an architect) believe me, this is not a good thing to do over those length of spans. Laminated sheetrock is quite heavy. A 2x4 or 2x6 is not going to do the job without sagging. Use of resilient channel on the existing joists would be much safer. There are also utilities and stringers and cross-bracing to deal with between the joists. Unbeknown to most folks is that the material used in the structure, whether it be a floor system, or a bridge, etc, is not so much to support the live load (the cars, trucks, people, funiture, etc). Its to support itself. Therefore, if 2x10 @ 'X' spacing O.C. is required to span a certain distance for the floor, nearly the same construction will be required for spaning a free standing ceiling below. Quote Link to comment Share on other sites More sharing options...
sfogg Posted August 4, 2004 Share Posted August 4, 2004 " A 2x4 or 2x6 is not going to do the job without sagging." I agree, and I did not say to use a 2x4 or a 2x6. "Therefore, if 2x10 @ 'X' spacing O.C. is required to span a certain distance for the floor, nearly the same construction will be required for spaning a free standing ceiling below." I agree, which is why on my upstairs floor joists I had 2x10@16". So for my new studs for just my ceiling (and about 3' less span) I used 2x8 @ 16". I talked to two civil engineers about this and my load requirements and both said this was plenty of strength for my needs. "Use of resilient channel on the existing joists would be much safer." Not if the new joists are properly sized. Resilient channel is also less effective (and more unpredicatable) and if improperly installed basically useless. "There are also utilities and stringers and cross-bracing to deal with between the joists." Been there done that. Luckily I had it easy as I just had to deal with cross-bracing and some piping for hot water heating that needed to be run all parallel to the studs to get it out of the way. Shawn Quote Link to comment Share on other sites More sharing options...
Arkytype Posted August 4, 2004 Share Posted August 4, 2004 Try these two sites for info on "soundproofing". www.soundproofing.org/infopages/channel.htm www.kineticsnoise.com I've used the Kinetics stuff to float a 4-inch concrete slab over a TV studio Believe me, that'll cut down on foot traffic from above!!! The TV studio walls were isolated from the rest of the structure by using some of their resilient wall anchors. The measured ambient noise level is NC17 and that's 75-feet from a state highway!! For residential applications, mounting drywall on resilient channels offers the most bang for the buck. Just build the room as if it was going to be filled with water. That means buying caulk by the case. Keep the vertical walls from touching the ceiling and caulk all the gaps. The best insulation to use is cellulose. When mixed with adhesive and sprayed on, it can be used to fill the void between your ceiling and upper deck. I'd also recommend it in all your walls. It will fill gaps better than Fiberglass and isn't a carcinogenic like Fiberglas. Because of its superior use as insulation from the cold or heat, it is naturally better than Fiberglas for sound insulation. Lee Quote Link to comment Share on other sites More sharing options...
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