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Spray-in insulation and acoustic absorption

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John Hiemburg:
Afternoon,


I've spent some time searching, and either this information is hard to find or I'm failing in my search.


We're building a metal building (16,000sf) to house a new sanctuary on the current church campus. Metal pre-fab. It will be exposed ceilings. The metal building mfgr recommends spray-in expanding foam insulation for its insulating properties, but I can't find any information on sound absorption for any of the available products.


I *can* find info regarding spray-in foam and sound *transmission*. In other words, there is a healthy amount of discussion about whether it is useful to stop sound from getting between rooms. This is not my concern. I just need to find some kind of data regarding absorption - I can pass that along to the acoustical consultant to design the proper amount of absorption for our room.


Am I missing a magical search term? Does anyone have any experience with this? Any other concerns or 'gotchas' with this kind of insulation that you've experienced?


Thank you!

Dave Garoutte:

--- Quote from: John Hiemburg on June 14, 2021, 06:39:42 pm ---Afternoon,


I've spent some time searching, and either this information is hard to find or I'm failing in my search.


We're building a metal building (16,000sf) to house a new sanctuary on the current church campus. Metal pre-fab. It will be exposed ceilings. The metal building mfgr recommends spray-in expanding foam insulation for its insulating properties, but I can't find any information on sound absorption for any of the available products.


I *can* find info regarding spray-in foam and sound *transmission*. In other words, there is a healthy amount of discussion about whether it is useful to stop sound from getting between rooms. This is not my concern. I just need to find some kind of data regarding absorption - I can pass that along to the acoustical consultant to design the proper amount of absorption for our room.


Am I missing a magical search term? Does anyone have any experience with this? Any other concerns or 'gotchas' with this kind of insulation that you've experienced?


Thank you!

--- End quote ---

The other advantage of the foam, is the irregular surface, helping break up and disperse reflections.

Bob Stone:
As far as I know, there's no spray foam that can be left uncovered on its own due to the noxious fumes if it ever catches fire. So what are they intending on putting over it?

John Fruits:
Have you asked your acoustical consultant?

Erik Jerde:
Thereís a few questions that need to be addressed.  First, like Bob noted spray foam in occupied spaces usually needs to be covered.  Iím not sure how this rule changes for commercial from residential.  When in doubt check with AHJ and mfgr specs.  Lacking a specific code citation mfgr specs win.

Second, what type of foam and to what thickness?  All my experience has been with closed cell foam but there is also open cell foam used in some situations.

Based on my experiences with closed cell foam Iíd expect it to perform like an irregular hard surface.  Fully cured closed cell is quite hard.  Of course you can dent it but I walk on 6Ē of closed cell in my attic with no worry about punching through or otherwise damaging the finished ceiling below.  Stuff is strong.  Definitely is not an absorptive surface.

Lastly, as far as the acoustician.  This is their job to figure out.  Thatís part of what youíre paying them for.  You should just be able to set out what you want the room to perform like and they should be able to figure out how to accomplish that.  Of course getting the budget to properly build the design is another thing entirely.  Hopefully youíve got a good acoustician.  I worked on a project a couple years ago where the building committee went against my advice on acoustician and now the back wall acoustic panels are reflective instead of absorptive.  Ugh.

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