Just starting out: Question about ICF exteriors

[AtomicBeagle]

Hi all -

Sorry if this is not the right amount of info, this is my first post and I'm still trying to get my plans together.

I am in the process of scoping out a new build home studio behind my garage. We are actually going to build a new garage (replacing the existing one), and I'm hoping to add the studio space behind it as part of the same structure. We have not had plans drawn up yet, but in preliminary discussions the builder has recommended ICF exterior walls for the studio portion and says this will give maximum exterior isolation (or at least comparable to MAM 2-leaf double walls). So I have a couple of questions before I start sketching out a design.

[Edit - I did not include the type of music to be played, or what rooms I hope to have. Here's that info:

1. Music being played will vary from acoustic to loud-ish rock music (no death-metal or nu-metal, but definitely some good old-fashioned fist-pumping rock).

2. I hope to have a live room, drum booth, control room, vocal booth, 3-4 iso amp booths.]

Questions:
1. Do ICF exterior walls compare favorably to the recommended MAM 2-leaf with double drywall assemblies from Rod's book?

2. If so, and I use ICF for all the exterior walls (including the wall between the garage and studio), do I then need to add decoupled interior walls (using 2-leaf double wall MAM design) inside the perimeter of the ICF wall? Or will the ICF wall work fine as my perimeter walls? I'm just trying to get a feel for what my exterior wall footprint will actually be before sketching things out.

I definitely have a lot more questions, but will try to sketch something out to provide the requisite amount of detail shortly. Thanks for any guidance!

[Soundman2020]

Do ICF exterior walls compare favorably to the recommended MAM 2-leaf with double drywall assemblies

From what little I've seen on the subject, I don't see how it can isolate as well as MSM principle. It seems to me that any isolation you get out of it would be simply due to the mass of the concrete in the wall, which makes me suspect that you'll be tied to mass law: 6 dB per doubling of mass. Maybe I'm wrong there, and you actually can build an ICF wall better than an MSM wall, but I don't see how.

the builder has recommended ICF exterior walls for the studio portion and says this will give maximum exterior isolation (or at least comparable to MAM 2-leaf double walls)

I think I'd look for some proper independent acoustic laboratory test results done on ICF walls, rather than just rely on the word of a builder with a vested interest, who thinks it might be better than an MSM wall. IF your builder is recommending it and claims that it is BETTER than MSM, then I'd ask him to produce some real acoustical data on ICF walls, from detailed tests done in a reputable independent acoustical lab, to back up his claim, rather than just "someone told me it would be OK". If he cannot do that, I'd be VERY wary. If you can get the data, it actually is favorable, and your builder can build the exact same way the test wall was built, then I guess you might be OK. But if not...

My question would be: Do you really want to be a guinea pig?

Just found this. Some interesting reading:

http://www.icfhomes.com/DYKpages/dykTRUTH.htm

Not much about acoustics in there, but plenty of food for thought. There seem to be plenty of ICF myths floating around! And there is this little gem in there:

“Won’t be able to hear your neighbor’s hot rod at 12 midnight”

This statement isn’t realistic at all. The ICF walls are only a small piece of the puzzle when looking at sound attenuation in relation to the exterior envelope of a house. The ICF walls do have a high STC rating for a wall assembly (approximately 50 decibel which equates to at least twice as good as a standard stud frame wall assembly, depending on how it is constructed) The windows, doors, roof, ceiling insulation and of course orientation to the noise source all play major roles in eliminating noise from the neighbor. ICF homes do feel quiet in comparison to wood frame, but ICF alone will not knock out all of the exterior noises.

So according to these guys, you can expect about an STC 50 rating from an ICF wall. Not bad, but probably not as good as you need.


- Stuart -

[AtomicBeagle]

Thanks Soundman! I think I'm more confused now, but only because I have more info to sift through.

So I wonder if my maximum exterior isolation could be gained from ICF exterior, plus a decoupled MSM interior along the perimeter? Or is that overkill, and just using a standard MSM assembly would do the trick?

I'm just looking for as much isolation for the neighbors as I can get.

Thanks again for any suggestions or guidance. I'm so new to all these considerations, I'm feeling a little lost in the woods...

[AVare]

Ouch. A tricky query to answer properly.

An ICF wall will end up being a triple leaf, with exterior and interior finished surfaces over the foam. Teh ICF provides amongst the cheapest mass per dollar, plus insulation of modern wall contructions. Mass is what is required for low frequency isolation.

The triple leaf wil NOT BE A PROBLEM if you build the exterior and interior walls with sufficiently different constructions that the MAM resonance of each side is different to avoid serious isolation degradation.

Perhaps the most significant item is that I have considered using ICF myself for studios.

Andre

[xSpace]

An ICF wall is mass, mostly...and air.

[Hagopm]

I'm also thinking of building my studio (control/production room) from ICF. Planning a decoupled slab too. Has anyone done it and did it work well for them? My studio will be a production/control room and I will also DJ from it.