Hi all.. I'm considering building a small, soundproof (hopefully) house, and am pretty sure ICF's are the way to go, but would love to hear experiences from those that are living in ICF (or other types) of homes. The things I'm trying to "attenuate" are barking dogs, backyard fireworks, screaming kids (in other words, the usual..). I was thinking of using double drywall + Green Glue on the inside of the roof (bonus space) and possible also in one or two other rooms, just to "make sure." Any comments appreciated! -m

pbrane...there are several stories that I'm sure that many from here have heard. One house I know of had an open house and during the event, apparently a car alarm went off. The neighbor across the street (some 150+ yards) had to stop by the house, knock on the door a ask the owner to turn it off.

One of the better stories in my opinion is the following...from ICF Magazine that can be found on the internet.

Saved From a Drunk Driver

It’s been just over one year since Mrs. Demczyk of Cape Coral, Fla., was awakened at 2 a.m. by a dull thud. Assuming the sound was caused by a household item falling to the floor, she got up to find the item and put it away. To her surprise, what she found was a set of headlights just inches from her living room window.

According to police reports, the Pontiac Firebird was racing through their neighborhood at more than 90 miles per hour when the driver lost control of the vehicle, left the roadway and slammed into the exterior wall of the Demczyk’s residence. Alcohol was a factor in the crash.

The wall’s sound class rating of 48 had reduced the sound of the deafening crash to a barely audible thud.

“I believe the Polysteel wall saved my life,” says Ray Demczyk, owner of the home. Demczyk says emergency workers on the scene told him the car would have penetrated the residence had the walls been made of concrete block or wood.

When asked if he was surprised by the strength of the wall, Demczyk responded, “I have known that this house was solid since the day I built it. Strength, wind resistance, and insulation are the reasons I chose Polysteel.”

Though the car was completely totaled, thankfully, the driver survived the collision without major injuries. The strength of the home’s walls was evident when the cleanup was completed. The only damage was a 3’ x 5’ section of the exterior finish that had been crushed by the impact.

With that impressive demonstration of strength, the Demczyk’s chose to stay put when Hurricane Charley roared through their town less than three months later.

As the wind gusted to 165 mph, the family heard very little noise from the storm. “We knew the wind was screaming outside and we could see major debris flying through the air, but inside the house remained quiet.” Ray says. “Large hardwood trees and palms on our property were completely uprooted or snapped in half yet the main house was completely unharmed.”

ICF would be the way to go.  I would not do the second layer of sheetrock.  I would invest in better windows and extra attic insulation.  The only sounds that penetrate the wall have to be large enough to vibrate the superstructure.   I built close to a Army training center and the 50mm rounds could be heard outside but not in.   

Having lived in and built Polysteel houses for 8 years.  I only got sound from my 8'x8' sliding glass doors and thru the attic (until i blew in at total of 18" insulation).  Carpeting in another HUGE factor in sound control.  I suggest waffle rubber and then slab rubber.  It make a difference.
 

Mass counts in acoustic attenuating, concrete has lots of it, and you rightly assume the roof doesn't (unless you have a tile roof?) Do you live in the flight path of an airport, or is it the kids & dogs in the aerial balloon that you're concerned about? :-)

Adding 5/8-3/4" of gypsum to the roof interior would add another ~20dBA of attenuation- definitely a noticable difference.

But dlahue's approach is probably the best- put the mass in insulation: 18" of cellulose adds up to about 2.2-3lbs/ft^2- about the same amount of mass per square foot as 5/8-3/4" gypsum (settled densites are ~1.5-2lbs/ft^3, so times @ 1.5' of depth you're at 2.25-3lbs/ft^2). But being fibrous it's also an acoustic absorber, and will probably beat the gypsum's attenuation while boosting your R-value into the super-insulation zone, (way over R50, probably over R60) with payback on a couple of levels. The material is cheap ($0.40-0.45/lb) and the labor for open-blow attics, not so much. Get quotes, and have it quoted by the POUND, not R-value or depth.

In cathedral ceilings, specifying dense-packed cellulose @ greater than 3lbs/ft^3 also works. A 2x10 rafter is 0.75 feet thick, which if dense-packed to 3lbs/ft^3 would give you the same mass & roughly the same attenuation as 18" of open blow on the attic floor or an additional 5/8" layer of gypsum. The 2-hole method lower-density cavity installation runs about 2-2.5lbs./ft^2 for cellulose so even that is still a decent mass from an acoustics POV. (If you had been planning on fiberglass batting, blown insulation will have better thermal performance, whether fiberglass or cellulose, but the cellulose will normally be denser.)

1000 square feet of attic floor is still less than $1KUSD of material @ 2.2lbs/ft^2. In a simple house design that's on the order of 10man-hours of work, prep included, maybe less. 5/8" sheet rock will cost ~$0.20-0.25/square foot, but the installation is more labor intensive. Wherever you can insert the mass via cellulose insulation you get the double-benefit for similar money, or essentially no cost adder, if you were planning to use FG batting insulation. The density of cellulose is greater, and the installed cost similar.

pbrane, Consider ICF walls, and a SIP roof, hard to beat, particularly if you're looking at having a conditioned attic "bonus space", as mentioned in your post. There is a vast amount of information, and opinion, concerning these two building systems contained in the various forums on this website, as well as throughout the internet.

Also, designing and building a home doesn't have to be a science project" unless you want it to be. Both ICFs and SIPs are proven, tried and true, engineered building systems, that will deliver "as promised" when properly installed.

Good luck with your research, as well as with your project!

(Thinking off the top of my head...) SIPs are great from an insulation point of view, but they're (almost by definition) low-mass, and only provide ~28-30dBA acoustic attenuation for a bare-naked SIP, no siding, roofing or gypsum added. (This is similar to 24" o.c. stick built + fg insulation.) Adding extra gypsum would boost it to ~60dBA total.

But a back-vented roof deck over a SIP roof (advised for many/most areas over a roof SIP to reduce the mold degradation hazard) you get lower mechanical coupling + some mass. I'm not sure what the actual attenuation factor of the vented deck would be, but it HAS to be at least as good as another layer of gypsum.

Another good way maybe an ICF Roof which provides more mass for sound attenuation / high STC ratings - look at our Quad-Deck ICF for Floors and Roofs. It can accommodate pitched roofs (in professionals' hands) - see pictures, and some decide to use it as the attic floor and then add a truss roof.

Happy Building!

I live in an ICF. We have a neighbor to the east who set off fireworks last July until 3:00 in the morning. Our neighber 1500+ yds. to the WEST stayed up until the fireworks died down while we slept through it. The only way you could hear it was through the windows. We both had our windows closed with the air conditioning running.
I used to drive a F-350 deisel. (you know how loud those things are) My wife NEVER heard me pull in. We built our house directly in line of a private runway. We can barely hear the airplanes take off or land. EXTREMELY QUIET!
If I did another house, I would put in triple pane windows to deaden the sound even more.
We did have 7" of foam sprayed on the roof deck. It is amazing all of the noises you don't hear. (Wind, rain, birds, cars, tractors, airplanes, etc.)
I can go on and on about ICF's. There is no way I would go back to wood framing.
Hope you enjoy.

www.tripadvisor.com, check the comments for the tifton comfort inn and suites in tifton GA, ICF hotel right on I-75, lots of comments about how quiet it is.

Wow...I'm impressed with the knowledgable folks on this forum. Thanks for the great responses, everyone. It sounds like if I want to have a quiet house, ICF's are the way to go. My builder mentioned the possibility of doing a SIP roof, but he hasn't used them much. We're meeting again this week, so I'll ask again. I'm still a little confused about the best way to go with the roof. I had not thought of the mass of the cellulose as a factor. I know some green builders here (WI) that will blow in a few inches of foam, then fill the rest with cellulose. This seems like a good combo to me. Regarding using double drywall, I didn't hear anyone comment on the Green Glue. I wouldn't bother to do double drywall without using GG in between...especially on the roof of the bonus room. And yes, I will try to buy the best windows I can afford. One of the good things about ICF's is that it gives you a deep window casing to work with. I will consider a good dual pane window, then buidling my own plexiglass interior storms, possibly with magnetic strips for attaching (but not sure yet..). Thanks again! -michael

I currently have a full SIP home, and for a quiet factor, I would not go for a SIP roof. It is really quiet except when it rains, the pitter patter definately goes through. Anything else is really quiet... On the main floor though, you never know it is raining, no matter how hard, unless you look out.

I am currently building another home at the moment, and am using ICF basement and SIP upper walls, with a standard energy truss roofing system, with an R-60 in the attics. I am really looking forward to it being done...

Buy a ranch in Wyoming to avoid the sounds...

But reallly...
1. ICF with triple pane windows - casement seems to seal tighter
2. Seal windows and doors, so not air leakage.
3. No SIPS on roof... use R-60 of cellulose in attic
4. Think about where vents point - might be good vent solutions are
5. Quiet Solutions, Green Glue and Owens Corning might be appropriate for some situations

The density/type of fiber insulations can be a ~5dB difference in performance over a wide spectrum, and being absorptive of mechanical energy, the difference is more than would be provided just mass alone (like extra gypsum.)  When it doubt, go higher density unless it makes it more rigid. See:

http://irc.nrc-cnrc.gc.ca/pubs/ir/ir832/ir832.pdf

All fiber insulations beat SIP attenuations by a few dB, since the EPS is more mechanically rigid, but the bridging of the studs/rafters keeps it from attenuating even more. Bare-naked SIPs  attenuate similarly to 2x4 wall (IIRC that's of almost arbitrary SIP thickness, but I don't remember if that's with or without fiberglass in the studwall.)

Foam + cellulose IS a good combination, since the foam provides the perfect air seal that cellulose alone can't, and the cellulose provides hygric buffering & thermal mass that the foams can't.  (IIRC dense-packed cellulose walls have about 1/4-1/3 the thermal mass of a concrete wall of equal thickness, and standard-density cellulose walls have about 1/6-1/5 the thermal mass.)  And the $/R-value of cellulose makes it an all-around value leader.

According to their test data  GreenGlue inserts another 6-10dB of attenuation into a standard 2x4 R13 FG wall assembly with double-gypsum both sides:

http://www.greengluecompany.com/images/greenGlue-vs-ExtraDrywall/Chart1-EffectsOFGreenGlue.gif

...and roughly twice what you get out of just doubling the gypsum of a single layer assembly:

http://www.greengluecompany.com/images/greenGlue-vs-ExtraDrywall/Chart2-EffectsAddingMass.gif

What they DON'T get into in their marketing is the added affect of thicker walls and denser insulation, which doesn't make them look quite so favorable as when compared a 2x4 studwall, since the absorption & mass of even thicker/denser insulation is also a performance enhancement.  A 2x12" rafter with 2" of foam &  9"+ of cellulose of isn't a 2x4 partition wall with mid-density fiberglass- it'll outperform 2x4 + FG attenuation by quite a bit.

That said, another 5-10dB of attenuation with a GreenGlued layer of gypsum is the perception-equivalent of reducing that already-attenuated sound by about half.  If you go ahead and build it out complete with insulation & roofing but just rough in the gypsum you can run a test with the baddest noise sources you ancipate to decide whether it's worth it to add a green-glued layer. (I'm gonna guess that for most, it won't be necessary.)