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Caleb DeFord Posted: Apr 19, 2012 09:54 PM	Wild and Crazy Spray Foam Questions Every once in a while I get some off-the-wall questions from people about spray foam. Example: "I had a guy tell me that he went to foam school and they told him that if you put closed cell foam inside a steel building it will echo worse even if you put open cell foam on top of it and then line the inside of the building with steel. Open cell foam doesn't increase the echo, but closed cell foam will." Obviously, that concept defies the laws of physics, acoustics, and sanity; but some people don't know any better. I don't need help answering questions like this, but it sparked my memory on the sound thing: Have any of you heard (or experienced)that foaming the attic (un-vented attic system)can cause sound coming up from one room to echo back down into the adjoining rooms? Seems like I heard that happened somewhere once. The other thing I wanted to say was: If you have some wild questions from customers or building trade professionals, put them up on the forum so that everyone can get an education on what kind of myths and "lies" are being propagated by the mouthy know-nothings of the building trade industry. -Foamilyman
John Cottle Posted: Apr 20, 2012 08:31 AM	Interesting! I was just told the same echo story yesterday. First time that I had heard it. I wonder if it was on a DIY channel or something
Caleb DeFord Posted: Apr 21, 2012 09:30 AM	Really? Who told you? This is what the guy I talked to said: ====="While I was at school i was asking them about covering up closed cell with another foam not only in a steel building but any type. They told me the only way to reduce the sound would be to rip out the closed cell because it was a sound enhancer. The project I was referring to ended up ripping out all the closed cell and stuffed fiberglass insulation up there, because the garage was under the offices and the noise was much worse after they put the closed cell in."===== I'm still after more details, but if anyone has more info on where this stuff originated, I would be grateful for any information y'all could impart. -Foamilyman
mason Posted: Apr 24, 2012 01:26 PM	While closed cell foam stops airborne noises such as cars, planes etc. because of its density, can transmit noise that is caused by an impact such as rain, hail or other falling objects. I guess because it air seals the building that sound would also not be able to escape from the interior, so I could see a little bit of an echo effect. But, installing cellulose or open cell foam over it should reduce, minimize or eliminate that concern.
mark moyer Posted: Apr 24, 2012 10:19 PM	now mason,,,lets stop the i suppose right here,,, buildings with closed cell foam are quieter during rain,hail,rock music or whatever,,,than buildings without,,,they do not echo care to bring out. a decibel meter? ask em to come visit"... i am tierd of the crap
mark moyer Posted: Apr 25, 2012 08:15 AM	...i heard spray foam in ur home will cause ur man childs to grow boobs... serious!!!big ones!!!OMG!! heard it at class,,,,low,,,but class none the less burma shave
mason Posted: Apr 25, 2012 03:05 PM	Foamdude, Have sprayed hundreds of metal buildings over the years. Closed cell foam will cause rain to sound funny inside the building, not loader just different, it doesn't muffle the sound, It does depend also on how thick the foam is. We typically only sprayed 1-2 inches. Thicker applications would transmit less vibration noise that I refer to.
Caleb DeFord Posted: Apr 25, 2012 03:08 PM	Here’s the deal on the spray foam sound and echo story: Acoustic control is rated through two systems, NRC (Noise Reduction Coefficient) and STC (Sound Transmission Class.) The STC rating has to do with sound being transmitted through a material and the NRC number has to do with noise being absorbed/reduced by a material. An NRC rating of .20 means that the material absorbs 20% of the sound that hits it and reflects 80% of the sound that hits it. An STC rating of 50 means that the material is reducing the sound transmission by 50 dB, and a rating of 60 means that it’s reducing the sound transmission by 60 dB. The basic standard for construction is that a quiet wall should have at least a 45 STC rating. Open cell foam has an STC of ~39. (3.5 inches thick) Closed cell foam has an STC rating of ~37. (not sure how thick) Fiberglass doesn’t have an STC rating, but the use of fiber glass batts within a partition assembly can increase the STC rating 4 to 10 points. Keep in mind though, that you really aren’t going to get the full STC rating of a given material because you have studs, plumbing pipes, electrical boxes, doors, windows, and wall liners in the system too, and they all affect the STC rating of the whole wall assembly. Closed Cell spray foam cannot make an echo worse unless it is sprayed over a substrate that has an NRC greater than .20 because closed cell foam itself has a NRC rating of .20. By comparison, open cell foam has a NRC of .70 and fiberglass has an NRC rating of .90. Please keep in mind that these are lab test results, not real-world test results. Steel, wood, and concrete all have an NRC rating of .01-.15 and most likely, in the typical steel building, the NRC number will be a big fat ZERO. With an NRC rating of .2 for closed cell and .7 for open cell, spray foam will not “enhance” noise and it will not increase echo. That being said, if we are talking about noise coming from a parking garage through to an office space, low frequency sounds (like from engines and banging car doors) aren’t going to be significantly reduced with any insulation material, and foam could not possibly make the STC worse than “no foam.” Oh, and when I called the “foam school” referred to by the guy I talked to, they said that they never taught him anything about sound control/echoing with spray foam. -Foamilyman
mark moyer Posted: Apr 28, 2012 05:18 AM	mason,, i too have sprayed hundreds,, and am still spraying them,,, respectfully,,come on out to the cornfield and bring a decibel meter... we have big rain,,, and it does indeed nock it down,, why the last 200x80 we had 1/2 shot and it started to rain,,in the first two bays shot you could stand and talk,,sound wasnt different or muffeled but indeed reduced to a comfortable level..2"sides,,3" lid,,but the bay not shot..loud.. foamily,,nice writeup on nrc stc,,,teach your children well..question is in our market caleb..why..so your buddy can use their new found knowledge about everythingfoam to sell against you claiming they know it all?? sell it to em next time like everyone else.. god bless...
Caleb DeFord Posted: Apr 30, 2012 12:06 PM	foamdude, I don't dig you. Are you saying we shouldn't explain about "everythingfoam" on the forums because our competitors ("buddies") will learn and then be able to better compete against us? And as far as the stc/nrc stuff, I just skimmed the surface, there's a ton more I could have said, but I didn't want to bore everybody. Sound control is a big and weird animal and it is very difficult to fully explain and understand. Even after spending a good deal of time studying it, I still don't really get all the stuff about stc/nrc. I just try to learn what I need to know to be able to give my customers the accurate information they need to keep them from having problems with their building. -Foamilyman
mark moyer Posted: May 01, 2012 04:15 AM	you dig me when you call me for free advice,, what you bought a banner add and it made you a hot shot??? cripes caleb,,, yep i meant what i said about teachin you!!! dig dat doggie!!! you never even bought me a beer..lol you wanna play big boy??? put the gun in your hand... now head back to the internet and learn all you can and get all puffed up with your new found wisdom,,im going to spray some foam and make some bling,,, facts from the tech data sheets of the foam i am shooting today,,,facts oc nrc 0.10 stc 42 cc nrc 0.10 stc 38 question is,,,compared to what??lol now have a nice day... oh yeah,,and god bless if the shoe fits
Terrance Harris Posted: May 02, 2012 05:41 PM	foamdude. would like to contact you via e-mail but do not have your e-mail address.
Doug Commette Posted: May 02, 2012 05:48 PM	click the email icon next to his name. this will allow you to send him a private message.
mason Posted: May 03, 2012 08:33 AM	Foamdude, never said that ccSPF would make the sound worse, just that it doesn't stop the sound, it muffles it and makes it sound kinda weird. I might not have been clear on that re-reading my posts.
Caleb DeFord Posted: May 04, 2012 12:14 AM	dude, You're so out-a-control already that the last thing I would think about doing is buying you a beer!:-) Just kidding! Seriously though, You want to know why I posted the NRC/STS stuff? Because I wanted to know about it from the forum long-beards and they didn't say didely, and because that subject has never been very well addressed on this forum. I would have loved to see some more knowledgeable input from any body else on the forum that wanted to chime-in, but I guess nobody else seems to care too much about the sound control properties of spf. So be it. I hope you had a fun day spraying. -Foamilyman
mason Posted: May 04, 2012 08:56 AM	This data comes from Mark Bomberg's book Spray Polyurethane Foam in External Envelopes of Buildings ?Table 19 Sound absorption coefficient of polyurethane foam with density of 32 kb/m3 (2pcf) Frequency 125 250 350 500 1000 2000 4000 NRC .12 .18 .20 . 27 .19 .67 .22 .32 The test states "The closed cell structure of SPF does not produce good sound absorption. Nevertheless, SPF can contribute to noise reduction by reducing the "drumming" effect of some sheet materials and by reducing air-born spread of noise." "The OCF type of SPF may have a significant effect on sound reduction if applied in sufficient thickness. "
John Shockney Posted: May 04, 2012 11:41 AM	? Doesn’t the cotton insulation made from recycled jeans do a better job of sound reduction?? Airpro
Caleb DeFord Posted: May 05, 2012 06:25 PM	Better than what? Foam? Probably, yeah, but I doubt that cotton insulation would be any better than cellulose. I have a test that shows that one of the best insulation systems for a good STC number (without building a double wall) is open cell foam with cellulose on top of it. That system tested out at STC 51. But then, if there's a loose fitting door in the wall that's obviously going to reduce the STC number regardless of how the wall is insulated.(duh) -Foamilyman
mark moyer Posted: May 06, 2012 07:45 AM	gunslinger,,since emails are bouncing.. are we being filtered doogles???? mark moyer foamdude midwest poly-solutions ltd 1143 briar drive iowa city iowa 52240 319.356.6500 voice and fax 319.400.3626 my cell foam-it@midwestpoly.com foamdude@midwestpoly.com foam-it@mchsi.com drop me a line if you care to,,, dude :)~ ...and the smiles are free,,,
quentin Posted: May 07, 2012 10:10 AM	Here is my 2bits on experience. Closed cell on metal ALWAYS since it prevents it from vibrating as much in the first place and reduces noise. I have done tons of pole barns this way and all are very quiet during a storm once they put the walls up. You have to put your ear to the wall to hear the rain except through doors and etc. In a normal house with normal walls and to reduce noise, you use open cell. Basic thoughts and experience say closed cell to stiffen things when it is impact or low frequency noice you want to block and open cell for high frequencies like people talking or etc. Even then, room to room it seems to work better using a mix since sound is vibrations. With a wall, the transmitting is from one room having noise causing the drywall in it to vibrate, causing the studs to vibrate and then the drywall in the next room to vibrate. So really what is the best way to stop that? You can apply closed cell to stiffen it up and absorb some of the vibrates too or hopen cell to try and absorb it. You have to look at each case and ask questions to find the best solutions then. If they have a floor above them they want quiet, jump on the closed cell at 3in to glue it, if it is talking then open usually works better in my experience. Want it really quiet? Do a mix of closed cell with open over it or closed cell and spay paper or cotton batts over it since it will cover the various frequencies of sound better that way. And think I am wrong on the lower frequencies? Take a look at those who compete in car audio. They line the vehicles with asphalt based sound deadener and heavy steel panels and extra thick glass to stop materials in the vehicle from vibrating in the first place. You want the sound to STAY in those vehicles since it leaving them, echoing or etc reduces the performance inside for these competitions that hit well over 150Db. BTW, standing right behind a jet at full power is about 140db and each 10db increase is a double of the previous so you get an idea how loud those competitions can get inside a vehicle. Hint, car audio drag racing record is over 177Db.
John Shockney Posted: May 08, 2012 09:29 PM	Ok enough about sound!! How about this: Customer calls wanting a price to spray one inch of foam on the underside of the roof in an existing attic leaving the venting in place! Tells me that another contractor told him “One inch of foam would reduce his A/C cost by 50%” And he didn’t even have any ductwork in the attic!!! After a long talk we mutually established that the most cost effective solution was to add more cellulose to his attic and there was no way to reduce his A/C costs by 50% without completely gutting and reinsulating the entire house. And even then there was no way to guarantee that!! Airpro
mason Posted: May 09, 2012 08:06 AM	Agree completely with exposing those folks who make ridiculous claims with spray foam. Long ago I had one contractor who claimed he could save a client 30% on his energy bills on UN-AIR CONDITIONED poultry shed by spraying 1 inch of foam.
mark moyer Posted: May 12, 2012 06:30 AM	..then we have the LARGE filterglass company that reluctantly got into foam and is shooting the itty bitty skim coat of 1/4 to 1/2" and covering it with an r19 batt as quick as they can hide their off ratio globs... useing 1" of foam r value in their total rvalue calculations and the contractors market that they are sellin a foam insulated home...and the home dont work any better than the pos filterglass home next door... thanks to our suppliers who are in bed with these folks! pushin hard to put us independants out of business,,and foam to the back shelf... god bless,,,
Tyler Boehs Posted: Jun 04, 2012 10:53 PM	foamdude, Haven't talked in awhile... Are you sure your not working in western nebraska??? We have the same thing going on out here and folks are buying it!! Where's the biggies when we need em!!!
Doug Commette Posted: Jun 04, 2012 11:15 PM	Mark: Please explain further the emails bouncing issue? not sure what you mean exactly?? you can send me a direct email if you want. we have a few issues with strange things going on since our new server upgrade a month ago. trying to track down any and all issues. thanks