Every so often, I write a newsletter on a subject I think might be of interest to both real estate professionals and their clients. You can find links to them below.
Many older homes in our area were insulated using vermiculite. This is an odorless, lightweight product made by exposing the mineral vermiculite to high heat, causing it to expand like a puffed-grain cereal. The resulting product is brown-grey to silver-gold in color and comes in small, roughly pebble-sized blocky chunks. These lightweight pieces were shipped in bags and poured loose into attics and wall cavities, where they formed an effective insulation layer.
Vermiculite itself is a harmless, inert substance. However, many naturally-occurring vermiculite deposits are found adjacent to asbestos deposits. This was the case for a large mine in Libby, Montana. That mine operated from 1919 to 1990, and supplied 70% of the vermiculite sold in the US during that time. Because the mine was strongly contaminated with asbestos and supplied such a large part of the market, it is safe to assume that any vermiculite found in a home built or insulated with vermiculite during that time period is contaminated with asbestos.
If you find vermiculite in a home, the best thing to do is to leave it undisturbed and take steps to insure it does not get tracked into the living areas. This means leaving the attic alone and not using it for storage. Caution should be taken during any construction or renovation work not to disturb the vermiculite and not to track it through the house. Sealing up any cracks or gaps in ceilings where dust might fall into the living area is also a good idea.
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