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  • Writer's pictureBonnie

Vermiculite Insulation and Asbestos

Updated: Nov 1, 2022


Kitty litter. If you see vermiculite insulation, it literally looks like your entire attic space is for felines.

Vermiculite insulation was commonly used in attics through the mid 1980s. Each piece is roughly the size of a tic-tac and has very fine accordion-style folds or ridges. When spotted in attic spaces, you generally see a mixture of grey, silver-gold, and tan colors.

Vermiculite Insulation Facts

Vermiculite is a naturally-occurring mineral that is very lightweight, fire-resistant, and can absorb six times its weight in liquids. It also does not rot, mold, or deteriorate. The R-value, which rates how well a material insulates, is R-2 for an inch of vermiculite coverage (fiberglass batt insulation is rated a notch higher at R-3 per inch).

The Bad Part of Vermiculite

Vermiculite ore develops under the same conditions as asbestos which means they are typically found next to one another in the mines. If you are mining for vermiculite, asbestos will likely be contaminating the harvested materials. This is an issue because we all know that asbestos is a danger to our health. So why not just pick it out? It's easier said than done. Asbestos is microscopic, and we're not talking the science fair level of microscope. You need an electron microscope which is an expensive piece of equipment. Because it would be terribly inefficient and economically unfeasible, the materials were never separated out. What makes matters worse is that there doesn't need to be a high percentage of asbestos in the vermiculite mixture before harmful levels are reached. The EPA approves the continued usage of vermiculite insulation in a home if it has less than 1% asbestos contamination.

What's The Big Deal with Asbestos?

Breathing in the dust or fine particles of asbestos is harmful. Asbestos is a carcinogen known to cause mesothelioma. Mesothelioma develops as a lining of the tissue (aka tumor) in the lungs, stomach, heart, and other organs. It most commonly affects the lungs and causes a cough, chest pain, and shortness of breath. When it is malignant mesothelioma, it is an aggressive and deadly form of cancer.

How Does Honeybee Report It?

Honeybee Home Inspection flags sightings of vermiculite insulation as an important repair and health hazard. Although testing the insulation for asbestos is the only true way to determine its danger, Honeybee recommends removal and replacement. There are much better insulation products on the market, so why mess with one that is potentially dangerous, less effective, and a messy form of insulation? I write it in my reports as

"Vermiculite insulation observed in attic. This type of insulation is noted as a safety hazard because asbestos is found in the same areas where vermiculite is mined, therefore it normally contains asbestos. Recommend a qualified professional assess and remedy or remediation if necessary."

Help, I Have A Vermiculite Situation!

If you already own a home with vermiculite insulation, don't disturb it. It's time to start researching into contractors that are certified in removing asbestos. For any contracting work, I recommend collecting at least three quotes and also to get the proposed work documented in an itemized quote.

If you are looking to purchase a home that contains vermiculite insulation, know that you may be able to negotiate the cost of insulation removal and replacement. As always, seek out certified professionals for this job.

Care to nerd out more? Let's continue!

Dark U.S. History of the Libby Mine

Vermiculite mining in Libby, Montana started in 1919 and was the largest mine in the U.S. This mine was contaminated with high levels asbestos, and the insulation product was marketed as Zonolite. The owners that took over the company in 1963 knew that the Zonolite was harmful, but they did not issue warnings. The mines continued to produce until 1990 which lead to decades of damage impacting the townspeople of Libby, the miners, and the consumers of the Zonolite insulation. It has been called the worst case of industrial poisoning of a community in U.S. history.

A great resource for more on Libby

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