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Is My Attic Insulation Asbestos?


Is My Attic Insulation Asbestos? A Visual Guide.
Identify Asbestos Insulation in Attic

Identify Asbestos Insulation in Attic

Photo Illustration © Lee Wallender; Licensed to About.com. All Images Public Domain.
Asbestos hardly needs an introduction anymore. Most homeowners, hopefully, are schooled in the general dangers of disturbing and breathing asbestos fibers.

But what about the specifics--namely, identifying whether your attic insulation is asbestos?

The main source of asbestos danger concerns vermiculite attic insulation, but not all brands or all sources.

There is nothing inherently bad about vermiculite, a pellet-like mineral that expands at high temperatures and which is often used for gardening. Vermiculite mined by the Libby company in Montana for about 70 years helped to produce the Zonolite brand of attic insulation. Zonolite presents a health danger only because it was contaminated with tremolite, an asbestos-like mineral. Even though the majority of U.S. vermiculite attic insulation did come from the Libby mine, keep in mind that about 30% did not come from this source.

Q: Was Your House Built Before 1990?

A: Because the Libby mine closed in 1990, houses built or remodeled before that date might have asbestos-containing attic insulation. If it was built after 1990, the chances are reduced but not eliminated.

Q: Is Your Attic Insulation Loose Fill or in Batts?

A: Batt-type attic insulation (long, narrow rolls that fit between the ceiling joists) almost certainly do not contain asbestos. Zonolite and similar asbestos-containing products are loose fill--many thousands of light-weight granules.

Q: Is the Fill Gray, Soft, and Without a Shine?

A: If so, it's probably cellulose insulation. Cellulose has a high recycled paper content, no minerals.

Q: Is the Fill White and Fluffy, With a Little Shine?

A: If so, it's probably fiberglass fill. Because it's a glass product, fiberglass will have a slight shine when subjected to bright light. It is very soft, almost like cotton candy.

Q: Does the Fill Look Like Firm But Light-Weight Pellets and With a "Mica-Like" Shine?

If so, you are probably looking at Zonolite. Zonolite is usually gray-brown or silver-gold and has an accordian-like texture. It lays flat and firm in the joist cavity, as opposed to loose-fill fiberglass which tends to puff up.

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