Does Mineral Wool Insulation Contain Asbestos?

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If you are purchasing a house that was built prior to the year 1990, you are probably worried the insulation may contain asbestos. Similarly, if you are re-insulating your attic or other areas of your home, you want to ensure the product you choose does not contain asbestos. We checked with top sources to bring you the best answer. See our findings below.

Contrary to popular belief, mineral wool is not known to contain asbestos. Asbestos is a naturally occurring fiber, whereas, mineral wools are man-made. Therefore, unless mineral wool is mixed with other naturally occurring fibers, you have no need to worry. 

Now that you know mineral wool does not contain asbestos, you need to know a few other basic facts. Keep reading as we discuss how to know if your insulation contains asbestos, whether mineral wool molds, how long it lasts, and more.

A worker insulates the attic with mineral wool, Does Mineral Wool Insulation Contain Asbestos?

Does Mineral Wool Insulation Contain Asbestos?

Generally, mineral wool is a blanket term for several types of wool insulation including mineral wool, rock wool, slag wool, balsam wool, and silva wool. According to Historic Buildings, all mineral wools are man-made materials.

Asbestos, on the other hand, is a naturally occurring fiber. Therefore, mineral wool does not contain asbestos. If, however, mineral wools are mixed with naturally occurring fibers to form insulation products, there is a chance those may contain asbestos.

Brown fiber glass insulation

What is Mineral Wool Insulation Made Of?

Mineral wool is a man-made material composed of rock, industrial slag, and other raw materials that have been melted down and spun into fibers to form a wool-like substance. Manufacturers then turn it into batting of varying densities, shapes, and sizes.

Roll of mineral wool lying on the wooden floor

Does Mineral Wool Mold?

Unlike fiberglass, mineral wool is water and moisture resistant. As such, it is not prone to mold, mildew, rot, or corrosion. Although mineral wool is water-resistant, that does not mean it cannot become wet. If it gets wet, however, it will not absorb the water into its fibers.

Instead, the water should drain from the material. You will need to let the insulation dry before using it, but once dry, it will regain its insulating properties. Furthermore, mold requires organic materials in which to thrive. Mineral wool is inorganic, thus it will not support mold growth even if it becomes wet.

How Long Does Mineral Wool Insulation Last?

House thermal insulation with mineral wool

If properly installed, mineral wool insulation will last for the life of your home. It will not degrade, corrode, or mold. However, if it becomes damaged and experiences loose fibers, it may begin to degrade and lose its insulating properties. For this reason, it is extremely important to make sure it dries fully if it becomes wet.

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What is Asbestos?

According to the National Center for Biotechnology Information (NBCI), asbestos is the name given to a group of naturally occurring fibrous minerals. These six minerals include chrysotile, crocidolite, tremolite, actinolite, and anthophyllite.

Companies utilized the minerals for manufacturing a wide array of insulation and other products prior to the year 1990. Scientists and doctors later discovered the minerals were highly dangerous and caused severe health problems such as asbestosis, lung cancer, and mesothelioma.

Bill Kibbel, the writer on Historic Buildings, notes that most asbestos-containing insulation comes in the form of vermiculite. Vermiculite almost exclusively comes from an asbestos-contaminated mine in Montana.

How Do I Know if I Have Asbestos Insulation?

Empty attic in the house with mineral wool insulation

The Center for Disease Control and Prevention (CDC) released a statement saying, "Although the use of asbestos and asbestos products has dramatically decreased in recent years, it is still found in many residential and commercial settings and continues to pose a health risk to workers and others."

The first step to knowing if you have asbestos insulation is discovering what type of insulation is in your home. Man-made materials, such as fiberglass and mineral wool, do not pose a threat unless it also has natural minerals in the mix.

If your insulation is vermiculite, however, there is a high chance that it contains asbestos. The chances are so great that the Environmental Protection Agency (EPA) does not recommend testing it to avoid any disruption which can cause fibers to become distributed throughout the air.

Testing

The only absolute way to know if you have asbestos insulation is to send it off for testing. However, as stated above, any disruption can cause the fibers to circulate through the air. Since any amount of asbestos exposure is dangerous, you'll need to weigh the risks before testing.

Although you can hire a trained professional to come in and take samples for testing, this method can be a bit expensive. If you prefer to collect the samples yourself, you can purchase asbestos test kits which allow you to collect your own samples. Just make sure to wear appropriate protective gear.

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Once collected and properly stored, you will use the prepaid postage to send the samples to the lab. The price of the kits typically include all lab costs. In many cases, you can even choose to have the results emailed to you within five business days of receipt.

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Determining the Risk

There are two different categories of asbestos products, one being more dangerous than the other. You can easily disturb Friable asbestos materials. Some such materials include contaminated insulation and talcum powder.

The other is non-friable asbestos material. This type is within products that lock it in and prevent it from releasing into the air. A couple of such products include contaminated cement slabs and floor tiles. Unless construction disrupts it, non-friable asbestos typically contains itself well. In this state, it does not pose a threat.

When to Test for Asbestos

If the suspected materials are non-friable, it is in your best interest not to test them. Since it does not pose an immediate threat, you should just leave it alone. Disturbing it for testing will send potential asbestos fibers into the atmosphere of your home.

If you have friable materials in your home that you suspect may contain asbestos, you may or may not need to test them. If the insulation is well contained, it is best to not disturb it. However, if you are planning to remodel your home, you will need to perform tests on any materials suspected to contain asbestos.

What to Do if I Have Asbestos Insulation

One of the most dangerous materials in the construction industry so-called hidden killer

If you send a sample of your insulation off for testing and it comes back positive for asbestos, you must determine if your family will be at greater risk of exposure by leaving it in place or by removing it. Removing asbestos-containing insulation will definitely disrupt the fibers.

If your insulation is well contained, it is likely best to leave it in place. However, whoever installed your insulation may have packed it loosly. Loose packing makes the insulation easy to disturb. In this case, you'll want to consider removal.

Additionally, if you are planning renovations, you will need to have the insulation removed beforehand. In some instances, you may be better off postponing your renovations and just leaving the insulation alone.

Asbestos Removal

If your insulation tested positive for asbestos and you have decided that removal is the best option, you will need to hire someone to perform the extraction. You should never try to remove asbestos on your own. There are certain guidelines professionals must follow during removal, and you should only hire accredited asbestos abatement contractors for the job.

Additional Questions

Here are some answers to related questions you may have:

Can Air Purifiers Protect Against Asbestos?

Certain air purifiers can protect against asbestos exposure. However, you cannot purchase just any purifier. Instead, you will need to ensure the device utilizes HEPA-certified filters.

If you discover asbestos-contaminated insulation in your home but don't want to take the risk of disturbing it, you can place a HEPA purifier in each room of your house to help capture any asbestos particles that may be floating around. You can even invest in vacuum cleaners featuring HEPA filters to help battle asbestos exposure.

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Summary

Asbestos is a legitimate concern among homeowners. However, it is a common misconception that mineral wool may contain traces of asbestos. Mineral wool is a man-made product, whereas asbestos is a naturally occurring fiber. Therefore, unless the mineral wool has other natural fibers in the mix, it cannot contain asbestos.

If you would like more tips on insulation, check out these other informational posts on our blog:

Can You Put New Attic Insulation Over Old?

Can You Over Insulate An Attic? [And what happens then?]

How Long Does Mineral Wool Insulation Last?

How To Install Mineral Wool Insulation In Ceiling [A Complete Guide]

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