Mineral wool is a popular insulation recommendation, but it seems expensive and has limited supplier options. I came across some info on perlite (and even vermiculite and lightweight expanded clay aggregate [LECA]) as a potential insulation material. I realize that it has a lower R-value per inch than others (perlite loose fill at 2.7/in, vermiculite 2.08/in), but if wall thickness were not a limiting factor, would it be a worthwhile consideration?
What if, for instance, you wanted to fill between AAC blocks or panels or a double wythe of concrete? Would perlite (or vermiculite/LECA) be a more cost effective alternative to mineral wool? Could it compete with rigid foam or cellulose? Would filling wall cavities be relatively low-labor?
There are properties of mineral wool that seem particularly attractive, and I’m wondering if these other minerals would provide the same. They would be similarly non-combustible and inorganic (no substrate for mold or termites), but I wonder if they would also have favorable properties for moisture or mass/lending any structural rigidity or strength.
I haven’t investigated very much yet, partly because communities like GBA don’t seem to ever mention these…which leads me to wonder if there are some major reasons to discount them.
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