Information for
-Home Buyers
-Home Inspectors
Follow Me on Twitter

National Relocation- for all your MOVING needs

Vermiculite Insulation - What is Vermiculite?

   Vermiculite insulation has gotten a lot of attention lately, and for good reason. The problem with vermiculite is that it may contain asbestos, which can cause lung ailments like mesothelioma and other adverse health effects.
   A mineral, vermiculite has a unique property that makes it a good insulator: it "pops" and expands when heated, much like a popcorn kernel or a foam packing peanut. In it's expanded form, vermiculite is shaped like flattened, fluffy chunks. The color of vermiculite runs from golden brown to light amber, and some vermiculite has a slightly irredescent sheen on it's surface, like mica.
   Vermiculite is quite fire resistant, has no odor, and is chemically inert.

Where Can Vermiculite be Found?

   Vermiculite is a very lightweight material, which made it a popular choice for thermal insulation from the 1920s to the mid-80s.  It was used primarily as attic insulation- vermiculite was poured between attic joists and wall studs in areas where other types of thermal insulation would be difficult or impossible to install. Since the vermiculite compacted and settled over time, it was sometimes supplemented with fiberglass or loose fill insulation between joists.

   From 1963 to 1984, vermiculite insulation was sold under the brand name Zonolite, and was available in large bags at many home improvement stores.  During that time period, the use of vermiculite insulation exploded, since it was a cheap, readily available insulation material.

   At the peak of it's popularity, vermiculite was used primarily to insulate older homes, many of which were built with no insulation at all. Cheap and easy to install in pre-existing homes, it is estimated that about 15% of U.S. homes and 10% of Canadian homes may contain vermiculite insulation material.

   Vermiculite can also be found in
                                                          - soil conditioners and potting soil
                                                          - thermal sound insulation
                                                          - gypsum wallboard
                                                          - fireproofing materials

   The vermiculite used in other applications poses a lesser health risk than it's use as an insulating material in the home, since the vermiculite is encapsulated in other materials when used for these purposes.

Where Does Vermiculite Come From?

    Vermiculite is mined around the world.
   In the U.S.,  there are active vermiculite mines in South Carolina and Virginia, and the material from these mines has been deemed safe.

   The main issue with vermiculite insulation, as previously mentioned, is that some vermiculite contains asbestos fibers.
   From the 1920s to 1990, the Libby mine in Montana (USA), operated by W.R. Grace, produced more than 70% of the world's vermiculite. It was discovered that the vermiculite from the Libby mine contained between .5% and 8% asbestos, with most of the material studied falling in the range of 1-2% asbestos content. The Libby mine was closed in 199

What Are the Health Risks of Vermiculite Exposure?

   When undisturbed, vermiculite poses little health risk to humans. Moving or disturbing the insulation causes the asbestos fibers to become airborne, where they can be inhaled and become lodged in the lung tissue.

  The asbestos fibers that are contained in the vermiculite have several health risks. Asbestos has been proven to cause:

- Asbestosis (a scarring of the lungs)

- Mesothelioma (a cancer of the chest lining and/or abdominal cavity)                                                                                                                                          - general breathing difficulties

  It should be clarified that NOT ALL vermiculite poses a health risk. Thus far, only the vermiculite taken from the Libby mine in Montana has been been found to contain asbestos fibers. Vermiculite was used as insulation even before it became widely available in 1963 under the Zonolite brand name, so vermiculite insulation that was installed prior to that date should also be considered a health risk.

   Generally, brief exposure to asbestos fibers poses a minimal health risk; asbestos-related health conditions normally develop after repeated or prolonged exposure to airborne asbestos fibers.
   If you have been exposed to airborne asbestos fibers from vermiculite in the home (or suspect that you have), then you should contact your physician or a pulmonologist for an evaluation.

What Should I Do About Vermiculite In My Home?

   The best course of action is to disturb the vermiculite as little as possible. If the vermiculite is between attic joists, it is best to encapsulate it with plastic sheeting or plywood so that the insulation cannot be stirred up, causing the asbestos fibers to move into the air. Limit your time in areas where vermiculite is present (most likely the attic) in order to limit your exposure. Seal up areas around ceiling fixtures so that airborne particles from the attic cannot enter the living space.

WARNING   A dust mask will NOT protect you from asbestos fibers, which are small enough to pass through a particulate mask.

WARNING    DO NOT use an attic that contains vermiculite insulation as a storage area; this will encourage activity in the attic, which will in turn increase exposure to airborne asbestos fibers.

WARNING    DO NOT draw combustion air or ventilation air from an attic that contains vermiculite insulation.

   You may opt to remove the vermiculite from your home to safeguard your family from asbestos exposure, but removal should only be done by a qualified, licensed asbestos removal contractor.

How Will the Presence of Vermiculite Affect My Home Inspection?

   Most home inspectors will examine the insulation material in the attic of the home, and comment in the home inspection report regarding the TYPE of insulation that is present,  it's condition, coverage, and degree of adequacy. In some cases, vermiculite insulation has been encapsulated with plywood or plastic, or covered with another type of insulation, and may not be visible to the inspector.

   If you (as a home buyer or seller) have knowledge about the presence of vermiculite insulation in the home, TELL THE HOME INSPECTOR for the safety of the occupants. The inspector will most likely put recommendations in the home inspection report regarding how to limit exposure to vermiculite that may contain asbestos. In most cases, the vermiculite can be isolated so that it's presence does not become a "deal-breaker".

The EPA maintains a toll free number for information about vermiculite 1-800-471-7127


All content Copyright 2009-2019  ALTASUP