Here’s one I haven’t seen before. I was in an attic of a 1924 home and the insulation used was 1 inch styrofoam chunks. My guess is someone had access to this material and just decided to use it in the attic. And my concern is that it’s combustible and puts off toxic fumes when it burns. Has anyone else run across this?
Nope. Never seen that. First reaction is that large chunks like that will be mediocre insulation as air will easily move around and between the large chunks. Secondly, in the case of a fire, the fumes will be a health concern, but the fire will still be the biggest problem.
Not sure I would have a recommendation. Saying it is a potential off-gassing health risk in a fire, is something we can say about many components of a house. That is definitely different.
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It might fit in the category of paper faced insulation. Or considered an accelerant. 
It is reason enough that I would not want it in my home.
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Good point.
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I certainly wouldn’t want it in my home either.
That said, has anyone ever torched a couch cushion? As the molten foam drips, it makes the coolest sound. This house would sound awesome on fire, viewed from a safe distance while everyone was standing around as it was intentionally demolished due to the health concerns.
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Yes, sounds like a space lazer, lol.
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Update: It definitely burns, and I suspect that with a real fire the liquified styrofoam would smolder. When I tested with a grill lighter the individual chunks would not sustain a flame, but this would likely be different with a high temperature house fire—I think it would likely act as an accelerant and put off toxic fumes. I’m just going to report it as an unusual setup and voice my concerns. Thanks for your help!
strong text
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yes remove and replace with correct insulation
EPS cubes.
Untreated EPS foam will burn at 650° to 700°F with a flame source. It will not continue to burn on its own until 840° to 930°F is reached.
Link to the source you stole this from (AGAIN)!!
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It came from here:
Asked & Answered: EPS Foam and Fire Retardants - BuildBlock Insulating Concrete Forms.
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Yes, I could have Googled his statement to get the source information myself, but I shouldn’t have to.
Also, the point being that Robert has a REAL BAD HABIT of stealing information from the internet without giving credit where credit is due, and trying to pass it off as his own in an attempt to sound smart!
Can you say “Plagiarism”?
This prevents others from digging deeper if they have more questions, and forces having to ask said questions from the person that failed to supply the source to begin with!
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If you read that article, which I assume you have at this point, you’ll realize it is likely a different product than what we are looking at. This shades the conclusion a little bit in my opinion.
I agree to you larger point, I always “show my work” as it were. I find no capital to be gained by obscuring data and I’ll be the first to admit when I don’t know something. In this field, there’s more I don’t know than I do but I’m working on it. I do know a lot about buildings, electric, HVAC, industrial automation and computers, so I’ve got that, but I what I don’t know, I don’t know. I had zero idea that EPS was used like that for insulation before today. I’ve seen panels and batts and what not, but not like that, so I do appreciate detail.
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I hope you were wearing at least an N95 respirator when you entered that attic.
Thats not styrofoam and likely contains asbestos (ACM).
I don’t think it’s Asbestos. I brought a few cubes home and was able to get it to burn. I run into Vermiculite regularly, and it’s really the only attic insulation I call out as suspected Asbestos.
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No way to know if its ACM without a test. Some early EPS manufacturer’s added asbestos fibers to their mix to enhance the strength of the material and reduce the flame-spread. I always wear an N95 when entering an attic thats older than 50 years old. Mesothelioma ain’t pretty.
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I haven’t seen that exact product before, although foam in many forms is used for attic and wall insulation. A fire wall is required between the foam and the building interior, typically drywall. Ya, the fumes are toxic, but so are many other household products located inside the home, carpet and curtains for one. The fumes from two part closed cell or open cell spray foam insulation is toxic. So are the fumes from the foam used in SIP panels. Those foam insulation products are used on many homes.
My concern is the large air spaces between the cubes. Convection heat loss through the large air spaces between the cubes makes this a very poor insulation.
I found a paper on the toxic cases created by burning foam of different types. Lemme see if I can find it.