Thread: White Lightweigt Powdery Insulation?

Found this in 2 sections of the upper attic and in the side attic areas. The home was built in 1983. The upper attic and side walls were fiberglass batts and this stuff was at the eaves about 2" thick. Never seen it before, any ideas?

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Looks like Granular Boric Acid. Added to keep bugs out?

Perlite Insulation?

Perlite | S&B

The following is from: Insulation: Insulation Overview - HealthyHouseInstitute.com

Vermiculite and Perlite

These materials are usually poured-in-place, sometimes in attics, but more often inside hollow concrete blocks. Vermiculite is a mica-like mineral that contains both free and chemically bound water. When heated, it expands due to steam being driven off. This puffed-up product is then used for insulation. It is naturally resistant to fire, rot, vermin, and termites, but is sometimes treated chemically to make it water repellent.

There is some concern about vermiculite containing small amounts of asbestos; however, the temperatures used in heating and puffing it up may cause the asbestos to decompose, yielding a less toxic product. Still, it has been reported that one particular vermiculite mine produced vermiculite with up to 5% asbestos. It is estimated that 70% of the vermiculite in use today came from this single mine, with the asbestos-contaminated product being installed in 940,000 homes. Fortunately, this particular mine was shut down in 1990. The Environmental Protection Agency (“EPA”) suggests that vermiculite should be treated like any other asbestos-containing material.

Perlite is a naturally occurring silicate volcanic rock. When heated, it expands, like vermiculite, because of a small amount of water turning to steam. Perlite is also fireproof and resistant to vermin. It is a very dusty material, and is often treated with silicone to control the dust. Its use in attics is often discouraged because the dust can filter down into the living space through light fixtures or other small openings. This dust can be problematic to an asthmatic, as can the silicone to chemically sensitive individuals.

When these products are used inside masonry walls, there is little chance of them or their contaminants reaching the living space (unless the walls have cracks in them and air pressure differences cause air to move through those cracks). Unfortunately, older masonry walls are often cracked. In older attics, the possibility that these products can get into the living space is even greater because older attics are often not sufficiently sealed. In new construction, extra care should be taken to insure that they stay inside building cavities and remain well separated from the living space.
Polystyrene beads

Polystyrene beads, which are often used as stuffing in bean-bag chairs, can also be used as loose-fill insulation. The beads, when expanded, are approximately an eighth of an inch in diameter. As with many synthetic foam insulations, they are flammable and must be protected from fire. Like vermiculite and perlite, they are primarily used to insulate inside masonry walls, although they can also be used in attics and other locations. Related health concerns are similar to those posed by polystyrene board products.