Vermiculite is a naturally occurring mineral which is mined and has been used in  household insulation and a variety of other consumer products because of its fire resistance and thermal insulation properties.  Sounds great, right?  Sort of.  The potential issue with vermiculite is that some, but not all, of the vermiculite insulation sold and installed in homes in Canada before 1990 may contain amphibole asbestos fibres.  Yup, asbestos.  Now that complicates things.  While vermiculite-based insulation is no longer sold in Canada, it was installed in many homes in the late 1970’s and 1980’s and still remains there today.


Photo courtesy of CMHC

How does this affect me?  Let’s ask the experts.

According to Health Canada, although the overall percentages of amphibole asbestos in bulk vermiculite are very low, the airborne percentages can increase if the material is disturbed (i.e. broken or damaged).  Asbestos poses health risks only when fibres are present in the air that people breathe. When asbestos fibres are fully enclosed or are tightly bound in a product (i.e. in asbestos siding or asbestos floor tiles), there are no significant health risks.

How exposure to asbestos can affect you depends on many factors, including the concentration of asbestos fibres in the air, exposure duration, the size of the asbestos airborne fibres, and the amount of time since the initial exposure. When inhaled in significant quantities, asbestos fibres can cause asbestosis (a scarring of the lungs which makes breathing difficult), mesothelioma (a rare cancer of the lining of the chest or abdominal cavity) and lung cancer.

What should your home inspector tell you?

As home inspectors, we consider it reasonable to assume that if your building contains older vermiculite-based insulation, the insulation may contain some amphibole asbestos.  Because of this, we always warn our clients of the potential risks. There is no way to know for certain if a product contains asbestos simply by looking at it. The presence of asbestos fibres must be verified by qualified laboratory technicians who will examine the fibres to make a determination. Your home inspector should alert you to the possible presence of asbestos and recommend that a sample be tested prior to closing the deal.

If you are considering the purchase of a home which is known to contain vermiculite-based insulation, consider the following:

  • Asbestos-containing products can cause health risks if disturbed during maintenance, renovation or demolition. However, according to Health Canada, there is currently no evidence of risk to your health if the insulation is sealed behind wallboard and floorboards, isolated in an attic, or otherwise kept from exposure to the interior environment.
  • Vermiculite-based insulation that needs removal must be removed by a trained and qualified asbestos abatement and removal professional. Get several quotes and be sure to build a budget for the removal into the cost of the home.
Clarified Home Inspections
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