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Why is vermiculite attic insulation a problem for both buyers and sellers of a home?

Monday, July 9, 2018

The presence of vermiculite insulation in the attic is considered “a material fact affecting the value of the home,” according the the Zonolite Attic Insulation Trust. In other words, it devalues a home. This is because it has been determined to be a health hazard, and may cause a buyer to walk away if not removed. The ZAI Trust fund was established in 2014 to reimburse homeowners up to 55% of the cost of removal of vermiculite insulation produced from a mine in Libby, Montana, that was the source of over 70% of all the vermiculite in the U.S. sold between 1919 and 1990.

     The trust fund was the result of settlement of a class action lawsuit against W.R. Grace Co., the owner of the mine, over asbestosis, mesothelioma, and other lung diseases attributed to their Zonolite brand of insulation product, along with the devaluation of homes containing it. 

  The insulation was manufactured by heating vermiculite ore to between 800º and 1100º C, which causes an accordion-like unfolding and expansion into the lightweight granules that were used for insulation. There were veins of asbestos in the mined ore that ended up in the final product, and it is estimated that between 3 million and 30 million homes have vermiculite insulation in the attic. Peak period of production was the 1950s through the 1970s, and the estimate of homes affected varies so widely because it was primarily sold for homeowner installation.

    Although the other roughly 30% of vermiculite sold in the U.S. came from mines that do not have asbestos contamination, the U.S. Environmental Protection Agency (EPA) does not recommend that you test the vermiculite insulation in your attic for asbestos content. There are several reasons:

  1. The asbestos is not evenly distributed in the Zonolite insulation and sampling may miss it or underestimate the overall level of asbestos in the product.
  2. The insulation in the attic may be a mixture of Zonolite and another brand.
  3. It was recently determined even less than 1% asbestos contamination of the vermiculite insulation is hazardous because the particular type of asbestos (tremolite) in the vermiculite is especially “friable,” meaning that the dangerous fibers are easily released to float in the air.

    What the EPA does recommend is that you have an asbestos abatement contractor remove it, and not disturb the insulation in any way until you do. Stay out of the attic, do not allow workmen to enter, and do not add or remove stored items in the attic. Also, do not try to remove the vermiculite yourself. The tan or gray granules may be partially hidden under a layer of new insulation, as in the photo below.

    Here’s the catch: the ZAI Trust only offers reimbursement for removal of Zonolite insulation produced from the Libby mine. You first have to file a claim, and then send them a sample, which they will chemically verify as Zonolite before processing your claim. If you find any empty Zonolite bags laying around the attic, send a picture of them along with your claim and it will help bolster your chance of approval. The reimbursement is for 55% of the cost of removal and replacement of the insulation, up to $7,500  of documented expenses (or a maximum of $4,125 reimbursed). If your sample comes back as not from the Libby mine, you are out of luck—but still need to remove the vermiculite, according to the EPA. 

   For more information, go to the Zonolite Attic Insulation Trust website at It has information and forms for a claim, sampling instructions, state-specific data, along with extensive other useful information. You may also want to visit the EPA webpage “Protect Your Family From Asbestos-Contaminated Vermiculite Insulation.”

    One final note: although many home inspectors are aware of the contamination of asbestos in vermiculite attic insulation and will point it out to you when observed, it is often concealed under newer insulation and inspection for asbestos or any other environmental contaminant is beyond the scope of a home inspection as defined by the Standards of Practice of all the major home inspection associations, specifically excluded in most home inspection contracts, and is not referenced as required by the Standards of Practice for Home Inspections of the Florida Department of Business and Professional Regulation.

    Also so our blog post What are the common problems with attic insulation?

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Here’s links to a collection of our blog posts about ATTICS:

What are the mistakes to avoid when doing attic improvements? 

What are the hazards to avoid when going into an attic? 

Does a home inspector check for lead paint?

What is the most common type of roof-to-wall attachment?

Is an attic required to have a light by the building code?  

What are the building code requirements for installing an appliance (furnace, air handler, water heater) in the attic?

How do I safely remove a dead rodent (rat, mouse or squirrel) from the attic?

Why is there no attic access hatch in the house?

How do I safely clean up rodent (rat, mouse or squirrel) urine or droppings the attic?

Why is there no attic access hatch in the house?

What is the building code requirement for an attic access hatch, scuttle, or door?

Why is vermiculite attic insulation a problem for both buyers and sellers of a home? 

What are the code requirements for NM-cable (nonmetallic-sheathed cable or Romex®) in an attic? 

What are the warning signs of a dangerous attic pull-down ladder?

Do home inspectors go on the roof? Do they get in the attic?

How much of a roof truss can I cut out to make a storage platform in the attic? 

• When was a fire separation in the attic first required between sides of a duplex? 

    Visit our INSULATION and ROOF AND ATTIC pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles. 

Photos - ZAI Trust

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