I have a client that has a great concern about noise penatration of his home. I suggested a engineer that would give us the details needed to meet his expectations but our client does not want us to spend the money. He wants us to just add more insulation. We have used the bib system in the past with good results but this clients lives close to an airport which makes me wonder if this system is enough. I wonder if anyone has seen any publications or experiance in this area.
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I can tell you this.
Windows are a great source of noise transmission, and laminated glass is far superior to plain old glass when it comes to that.
Packing a greater thickness of fiberglass or cellulose insulation in the wall cavities is worthless, but insulating with urethane foam is worthwhile. Costly, however.
Most all the major window companies that wish to market product in the southeast, have come up with products that meet the "hurricane code" standards in Florida, and up the coast through North Carolina.
Though double-paned ("insulated glass"), I believe that the outer glass pane is a laminated part.
Big upcharge, though.
Walk down the gate concourse of any airport and look through the glass. You're looking through a glass assembly of 1/4" on the inside pane, 1/2" airspace, and 1/4" laminated on the outer. Hear those jet noises? Not much.
For exterior opaque (read: "no glass") doors, choose wood doors, the heavier the better. 2-1/4 thickness is much better, in STC ("sound transmission coefficient") value, versus 1-3/4, and you can readily get hardware for 2-1/4".
For exterior walls, more mass is better, STC-wise. Consider sheathing in 3/4", versus 7/16". A stucco exterior helps greatly, versus a wood siding scheme. Stone is much better. Consider 5/8 sheetrock on the interior side of exterior walls, versus 1/2". All these things add mass to the wall assembly.
Edited 2/24/2005 12:10 pm ET by Gene Davis
Good points. An architect I know spec'd exterior door for the bedroom of a house whose owners wanted it quiet. Seems like that would work well.
I wouldn't have anything to do with him. If you do what he wants, just put in more insulation, it won't reduce the noise enough to suit him, and he'll blame you, no matter how clearly you explain it or how many waivers you make him sign. If he thinks more insulation will fix the problem, let him hire some hack to install it.
Or make him pay you in advance. Anybody who buys a house near the airport and then complains about the noise is a ####.
JLC has an article on this a couple of years ago by a contractor that was doing this for house near airports. IIRC it was heavy on the details of window replacement for sound control.
JLCONLINE.com and then Research to look up the articles.
Also some had an article, I think FHB on some sound control issues and you can also look those up online.
Also I hear the Carey Brothers advertise something from time to time. I think that is might be called SoundProof Windows are some thing like that. I think that they are some kind of internal "storm window", but not sure.
You mgith want to do some looking on their web site and see if it mentions them.
http://www.onthehouse.com/
Toby, if he wants you to add more insulation, then....add some more insulation.
The added insulation will help with the energy bills and the man will believe that it helps cut down on noise. He has already programmed himself to believe that an no amount of techical talk will change that.
blue
Just because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
he wants you to add more insulation, then....add some more insulation.
The added insulation will help with the energy bills and the man will believe that it helps cut down on noise
Well, true enough, unless the customer wants 5 1/2" batts in 3 1/2" bays. The "unreasonableness" of customers knows no bounds, after all.
Now, as an aspect of construction in an airway corridor, I'm thinking, just abstractly, that a modified Mooney wall system might not be a good idea. I'm thinking about decoupling the ceilings, particularly by using two top plates, an inner and an outer. The outer plate, on the outer studs would carry the trusses forthe roof. The inner plate (or ledger-iod) would "carry" the ceiling joists. This does not help the OP, I'm just cogitating on ti topic a bit.Occupational hazard of my occupation not being around (sorry Bubba)
CapnMac, all too often everyone wants to complicate things. If the guy wants more insulation, to deaden sound, I'd offer it in any thickness he wanted. If he wanted it 24" thick, I'd say okay, and build the wall 24" thick.
I wouldn't try to turn the house into a science project. If he wanted a science project, he would have asked for a science project, not more insulation.
KISS
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
Fiberglass batts aren't going to do anything for his walls (http://www.dulley.com/docs/f691.htm); The soundproof characteristics of a wall are rated by sound transmission class (STC). Normal conversation will be heard and understood through a STC-25 wall. When soundproofing is improved to STC-60, which is not difficult to accomplish, loud shouting can be heard, but not understood.For an efficient outdoor wall, just packing in thermal insulation, such as fiberglass or cellulose, will save energy, but it alone will marginally help to soundproof it. Making the wall airtight for efficiency will likely have a greater impact on blocking outdoor noise from traffic and neighbors.Interior walls in most homes are not filled with insulation. With a single layer of drywall nailed to 2x4 studs, the STC is about 34. This means loud talking can be understood through the wall. If the home is older with some settling, there will be gaps and openings to make things even worse.The minimum recommended STC for any bedroom wall is 48 and this for an adjacent bedroom which is usually not noisy. For a bedroom wall adjacent to a kitchen or noisy family room, a minimum STC-52 is recommended and an STC-58 is considered optimal. Noise tolerance level also varies with individuals.With an existing wall, just adding another layer of 1/2-inch drywall over the existing wall helps substantially with minimal floor space loss. This also will seal many of the gaps and direct air paths where sound waves move easily. Glue the new drywall in place, possibly with some cushioning sheet (cork) under it. If it is nailed up, this will create a direct sound path.If you can handle losing a little more floor space, first nail resilient channels up to the old wall. The new layer of drywall will be attached to these soundproofing channels. Another better, but more expensive option, is to attach special sound barrier fiberboard made from recycled newspapers.For new construction, use fiberglass insulation inside all the walls and hang all the drywall on resilient channels. A thicker staggered-stud wall uses a wide wall base plate so no single stud touches both wall surfaces. Vary the locations of heating register and electrical outlets so they are not directly across from one another on the walls in adjacent rooms.If you don't want to go that way AND low frequencies aren't the problem (from 200 Hz downward, or what we typically experience as footfall noise in a ceiling over our heads), then you'll need something more substantial (try Quiet Solution, at http://www.quietsolution.com) for the replacement sheetrock he's talking about. However, while that will get the walls up to an STC (Sound Transmission Class) of about 55 (kills 55 dbs of noise), the real weak spots will be the windows. An acoustically leaky window (think: thin, single pane, poor weather stripping on a double hung) might have an STC of 12.In hierachy, then, the most sound proof is a wall; then a wall with a fixed, 3/8" laminated glass, double paned and 8" inside of that, a plastic set of acoustic windows; then the fixed 3/8" laminated; then 3/8" double paned laminated in a casement; then 1/4" double paned laminated in a casement; then 1/4" double paned in a double hung with double weatherstripping (Q-lon set into routed/sawn grooves) at every surface; then 1/4" double paned laminated with single weatherstripping; then standard double paned, aluminum framed weatherstripped windows; then standard double paned, wooden windows.Any airspace is the enemy; Q-lon weatherstripping at two points of contact for every sash becomes part of the build (and a difficult one too, because if set up incorrectly, the windows will be hard to close!)Basically, it becomes all about 1) weatherstripping with Q-Lon, usually with TWO weatherstripping barriers on each window (to allow for failure points on the first) and then 2) how much glass and airspace between the glass you want to put in.First of all, there is a wonderful site that talks about the differences between regular single pane, double pane, laminated and doubled laminated, but unfortunately, the web page does not cover the diagrams, only the text http://www.findarticles.com/p/articles/mi_qa4075/is_200402/ai_n9355083). Nonetheless, it addresses the issues at hand.Then, there is a British site (get out your metric converter) that details the capabilities of laminated glass quite well (http://www.domesticsoundproofing.co.uk/windows.htm) and another site that also does a wonderful job describing the standard, manufacturer supplied double glazed window---with special notes on the better sealing characteristics of casements (also in metric; http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/98120.htm)To quote on their study of regular double glazed units:Following the testing, the window units were assigned Sound Transmission Class (STC) and Transmission Loss (TL) values, to indicate their acoustic capabilities. (Note: The higher the STC rating, the better the sound isolation properties of the window.)The research report’s key results are presented below (and summarized in Figure 1):The STC of the nine standalone thermopanes tested ranged between STC 25 and STC 34. The STC measured on the operable windows ranged between STC 27 and STC 41.Sealed thermopanes with a deeper airspace provide a higher STC rating and higher TL for frequencies above the MASS-AIR-MASS resonance.Doubling the thickness of one of the glass panes composing the doubleglazing thermopanes increased the STC by approximately 6 points.Three factory-sealed thermopanes constructed with spacers made of different materials (aluminum, PVC, and aluminum/neoprene) were tested and were found to provide equivalent STC and TL.The STC rating of 1200 mm x 1600 mm casement windows was approximately 3 points higher than the STC rating measured on 1200 mm x 1600 mm standalone thermopanes with same glazing composition, sealed in the test opening. In the case of the double hung sash window, the increase in performance compared to the standalone thermopane is 1 point of STC. The reason for those increases required further research.Casement windows built with aluminum, wood, and PVC and constructed with identical glazing provided similar sound isolation performance with STC ratings varying by 2 points. The maximum STC measured on casement windows was achieved by an aluminum window (STC 35) equipped with a double-glazed thermopane composed of one 3 mm glass and one 6 mm glass with a 16 mm airspace, followed by the wood (STC 34) and PVC (STC 33) thermopane windows with panes of equal thickness separated by a 13 mm airspace instead of 16 mm.Researchers noted that the deeper airspace in the thermopane of the aluminum window was probably responsible for the superior STC rating and partly responsible for its higher transmission losses.Comparisons between aluminum, PVC, and wood windows suggested that the seals and the sash composition of the aluminum window could also be responsible for the better sound isolation performance of this window at mid- and high frequencies.The casement window that offered the best ratio cost/sound isolation is the wood window followed by the PVC window and, in last position, the aluminum window.Combining the maximum STC rating obtained on a stand-alone thermopane measured in the present study with the maximum STC rating measured on casement windows, it appeared that STC 37 would be the maximum rating that could be obtained from an operable casement window equipped with a 25 mm thick thermopane.The aluminum sliding window provided superior sound isolation when compared to a PVC sliding window.The aluminum horizontal sliding window ranked first in terms of acoustical performance, and seventh in terms of price.And to return to the original thought:The best possible sound killer is a fixed (no chance of a weatherstripping failure), 3/8" laminated, double paned window with an airspace of 2 inches AND a set of plastic acoustic windows inset 6 inches from that; the STC of that window should exceed 50 dbs.However, who in the heck wants to live behind such a window? The only place you will find that is in the house of a desperate person or a recording studio.More realistically, 1/4" laminated, double paned glass in a fixed frame (1/2" air space) has an STC of 42 to 35 depending on the installation (http://www.1stwindows.com/glass.htm)Wish you luck!As you can tell, I've been thinking about this for a while.NotaClue
Sorry NotaClue, you missed the point.
The point is that this client believes that insulation will help. As a GC, you can spend a lot of energy trying to change this guys mind and ultimately you may very well succeed. In the process, you just might create an enemy, or maybe the guy will just become slightly resentful.
All I'm saying is that often, the homeowners have already done some basic research and have made up their minds. Once the house starts, I think it's counterproductive to try to win all the battles and ultimatly lose the war. My suggestion is to pick the battles carefully. In this case, if the guy requests extra insulation, because he believes that extra insulation will help, then the guy will ultimatly be more happy with the extra insulation because he's convinced that it helps. The power of suggestion comes into play here and instead of fighting it, simply embrace it.
You don't want to be right, you just want the client to be happy. He won't be happy dumping a ton more cash into something when he thought a little more cash could but that same happiness with insulation.
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
Just finished doing a basment studio.....stc >48 materials gonna cost ya!
I like a product called dB-block...basically you need something dense....lead works great...ha ha ha.
Caulk everything in site and somemore...use acuostical caulk.
I have also had good sucess using alternate thickness in the wall sheathing along with the channel systems. It all costs...H.O. is gonna choke for sure. If he's cheap don't even waist your time.
If you do wanna go further hope these help some...
http://www.auralex.com/sound_isolation_sheetblok/sound_isolation_sheetblok.asp
http://www.soundseal.com/
http://www.pac-intl.com/home.html
Just remember that the entire system is only as good as the weakest link. It will not pay to add all the insulation (even if it were effective) if the windows are the weak link. If night time noise is the problem one solution is heavy drapes over the window (with a significant overlap between the drapes and the wall to minimize leakage around the drapes.
Increasing the transmission loss through a boundary is dependant on two things, mass and density. Adding mass works by itself (but you may need a lot). Density works only when you have dissimilar densities in each layer. The noise sees this density change as a partially reflective surface causing some of the energy to bounce back to where it came from.
As others have said - don't promise to fix this guys problems without consulting an expert. And get noise measurements before and after so that the results are not subjective (you don't need to admit to doing the measurements until you know the results).
Chris
You know what?
You're right.
NotaClue
You know what?You're right.
maybe so, but thanks for the details in your post -
"there's enough for everyone"
That depends how the insulation is added, Blue. Adding insulation in the wrong way can actually decrease the R-value.
I partly agree with the psychology of this though.
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That depends how the insulation is added, Blue. Adding insulation in the wrong way can actually decrease the R-value.I partly agree with the psychology of this though.
Piffin, I understand that overpacking will reduce the effectiveness. I wouldn't suggest that. I'm assuming that any extra insulation done will meet manufacturers standards.
Basically, I'd just offer to got to 2x6's, 2x8's or whatever.
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!