Types Of Asbestos: The Ultimate Guide for Residential Homes

Date Published: March 26, 2019

Asbestos is a hot topic when buying older homes. It can be hidden, it can be expensive to mitigate, and is present in many building materials in houses built prior to the 90s. Plus there are many different types of building materials that contain asbestos.

Because of this, we decided to write this asbestos guide to help people better understand asbestos and the different forms it takes, whether it be asbestos tile, asbestos insulation, siding or some other common material.

What is asbestos?

Asbestos itself is a mineral substance. It is naturally occurring and can be broken into soft fibers that can be used to create products. When asbestos was first used and marketed in building materials, it was revered as a “magic material” as it could resist heat, was a good insulator and was virtually fireproof. Asbestos and insulation went hand in hand.

Asbestos Insulation Ad

In the middle of the 20th century, asbestos demand peaked and the hardy asbestos fibers were mixed into hundreds of products across multiple industries.

However, most of us know how this story ends. In the ’70s and ’80s, reports started to emerge that inhaling the small fibers of asbestos could cause health complications. Once the fibers enter the body, they never dissolve, and because the fibers are microscopic, they have no smell, taste, and cannot be seen.

From studies of people who were exposed to asbestos in factories and shipyards, we know that breathing in high levels of asbestos fibers can lead to an increased risk of lung cancer in the forms of mesothelioma, which is a cancer of the lining of the chest and the abdominal cavity, and asbestosis, in which the lungs become scarred with fibrous tissue.

Since then, the U.S. government has restricted the use of high concentration asbestos in all types of asbestos. But that still leaves us with many decades of asbestos products in homes that we need to be aware of.

So let’s break down its many shapes. Many products were made with asbestos. However, we are going to cover some of the most common, and then some.

Many Types of Asbestos

The majority of the products that we see in a home that might have contained asbestos in the past include:

  • steam pipes, boilers and furnace ducts insulated with an asbestos blanket or asbestos paper tape. These materials may release asbestos fibers if damaged, repaired, or removed improperly;
  • resilient floor tiles (vinyl asbestos, asphalt, and rubber), the backing on vinyl sheet flooring, and adhesives used for installing floor tile. Sanding tiles can release fibers, and so may scraping or sanding the backing of sheet flooring during removal;
  • cement sheet, millboard, and paper used as insulation around furnaces and wood-burning stoves. Repairing or removing appliances may release asbestos fibers, and so may cutting, tearing, sanding, drilling, or sawing insulation;
  • door gaskets in furnaces, wood stoves, and coal stoves. Worn seals can release asbestos fibers during use;
  • soundproofing or decorative material sprayed on walls and ceilings. Loose, crumbly or water-damaged material may release fibers, and so will sanding, drilling or scraping the material;
  • patching and joint compounds for walls and ceilings, and textured paints. Sanding, scraping, or drilling these surfaces may release asbestos fibers;
  • asbestos cement roofing, shingles, and siding. These products are not likely to release asbestos fibers unless sawed, dilled or cut;
  • artificial ashes and embers sold for use in gas-fired fireplaces, and other older household products, such as fireproof gloves, stove-top pads, ironing board covers, and certain hairdryers; and
  • automobile brake pads and linings, clutch facings and gaskets.

It’s a lot to absorb….

Even though we know it as inspectors, it is really important that we reiterate this to our clients, that even if the home has some of these products, or other materials known to sometimes use the mineral, it doesn’t necessarily mean they are in danger of exposure.

Asbestos is considered innocuous unless it is damaged or disturbed in some way, which could release the dangerous fibers into the air. It is important to make the client aware of its potential presence, however, to avoid any damage to such products from old age, or in the case of renovations.

Here is what the EPA’s states on its website:

Asbestos-containing materials that aren’t damaged or disturbed are not likely to pose a health risk. Usually, the best thing is to leave asbestos-containing material alone if it is in good condition.

Generally, asbestos-containing material that is in good condition and will not be disturbed (by remodeling, for example) will not release asbestos fibers.

Asbestos was banned in ceiling treatments in the United States by the Clean Air Act of 1978.

It is always prudent to be knowledgeable about asbestos, but also remember that asbestos was:

  • In blow dryers up until sometime in the 1980’s
  • Used in brake linings up until sometime in the 1990’s
  • Used in over 3,000 consumer and building products in the last century

So the likelihood of you coming into contact with undisturbed asbestos is very high. However, unless you are tearing it off walls or ceilings without protective gear, it is generally safe to be around it.

“The Big Five”

“The big five” are the 5 most common sources of asbestos that you will find in a home built before 1980. They are popcorn ceilings, square acoustic ceiling tiles, 9×9 inch vinyl floor tiles, heating duct pipe wrapping, and vermiculite insulation.

We are going to outline each of these below with images.

1. Popcorn Ceilings

Asbestos Popcorn Ceilings

There are millions of homes with textured popcorn ceilings and walls in the U.S., some of which contain asbestos materials. It is not possible to tell if there is asbestos material in the texturing merely by looking at it. In order to tell if there is asbestos, a sample would need to be sent to a lab. Many buyers choose to leave the popcorn ceilings just as they are; others choose to remove the texturing.

If the textured material has asbestos material in it, it can still be left in place. Generally, it is not an immediate health concern, unless the material is friable, damaged or flaking. Should a buyer want to remove the material on their own, there are certain guidelines and rules that should be followed. A professional contractor can also be hired to remove the material. Either way, EPA guidelines should be followed, with information available on the EPA website, as well as many state websites.

2. Asbestos Ceiling Tiles

Asbestos Ceiling Tiles

Asbestos ceiling tiles were commonly used in schools, universities, warehouses, hospitals, and colleges during this era. Asbestos ceiling tiles reached the height of their popularity from the 1950s to the 1980s and were a standard choice for office ceilings, kitchen ceilings in homes and even in the remodeling of basement areas in order to cover up unsightly ductwork.

It can often be difficult to accurately identify whether ceiling tiles contain asbestos or not. Asbestos was used in many different styles of ceiling tiles, in suspended ceilings, and was a very common material in tile insulation as the paper on the underside of tiles.

Asbestos Ceiling Tiles Square

Asbestos Ceiling Tiles Textured

Additionally, asbestos was used in the adhesive materials which bound the sections of the tiles together. As a general rule of thumb, if you encounter ceiling tiles in an older home that has a similar appearance to those of photos of asbestos ceiling tiles, you should get them tested.

Identifying asbestos can be difficult because asbestos ceiling products often look similar to ceiling tiles made without asbestos. Many ceiling tiles were produced with mineral woods, cellulose, and starch and then painted.

These products often have very similar appearances. Due to the large number and variety of different ceiling tiles produced, it simply isn’t possible to provide a comprehensive visual database of asbestos-containing materials.

3. Vinyl Floor Tiles

Asbestos Tile

Vinyl has been a popular choice for flooring throughout the modern era, and many building materials manufactured before 1980 had asbestos mixed into them to increase durability. Vinyl is a plastic resin manufactured from ethylene and chlorine. The substance is sturdy yet flexible, easy to wash and cheap to install and replace.

In addition, vinyl products can be manufactured with almost any color and texture, allowing them to provide the appearance of wood, stone and other traditional building materials at a fraction of the cost.

The most commonly produced vinyl tile product containing asbestos was the 9×9 inch tile that was sealed to the floor with adhesive. We still see this type of tile constantly during our inspections. It was especially prevalent in mid-century houses.

Asbestos Tile Vinyl

In as early as 1920, vinyl manufacturers often mixed asbestos into their products for greater strength and insulating properties, and construction companies favored asbestos-containing materials of all kinds as an essential component of fire-resistant buildings. Because both vinyl and asbestos were inexpensive and easy to work with, asbestos vinyl products became widespread.

Vinyl floor tiles are resilient and inexpensive, making them a logical choice for floors that must withstand constant wear and tear such as in businesses, homes, schools and hospitals. Mixing asbestos into vinyl floor tiles made them more insulating and resistant to damage.

4. Heating Duct Pipe Wrapping

Asbestos Tape On Ducts

Asbestos insulation was widely used on heating pipes, sometimes on water pipes, and occasionally on other pipes in buildings. This asbestos insulating product appears most-often as a gray-white corrugated paper but might also appear as a plaster or cementious paste on pipe elbows, valves, or on other irregular components.

Asbestos Tape Around Furnace Ductwork

The tape in these areas was used to reinforce or repair a leaky duct system. You may see this asbestos tape along the joints of an old duct system or around the corners to hold the joints together. In rare cases, the entire duct system was fully wrapped!

The product was used similarly to modern day duct tape or mastic. Luckly, its appearance makes it easy to spot.

5. Vermiculite

Asbestos Insulation Attic vermiculite 2

Vermiculite was mined in Libby, Montana, from the 1920s until the mine closed in 1990. While in operation, the mine in Libby produced most of the world’s supply of vermiculite. Vermiculite has been used in building insulation, potting soil, fertilizer, and even in the bottom of vented gas fireplaces to give the flame that extra “special glow”.

Unfortunately, the vermiculite from the Libby mine contained a type of naturally-occurring asbestos called tremolite-actinolite.

Asbestos Insulation Attic vermiculite

Vermiculite was a popular attic insulation material used during the turn of the century. You see the highest concentration of it in houses built from 1900-1940s. After this time period, rock wool insulation became the go-to attic insulation product.

Not all vermiculite contains asbestos; however, some products have been made with vermiculite containing types of asbestos. Pieces of vermiculite are brownish-gold and are about ½ inch in size. Pieces look like they are made of several layers.

However, removing vermiculite that has a high concentration of asbestos can be tricky. It usually requires sucking out the material with a specially designed vacuum. This can kick up a lot of the asbestos fibers so often the home needs to be sealed off during the process.

In Summary…

From our experience, a home inspector performing an average of 10 inspections a week will come across these common asbestos-containing materials, in one form or another. So we are always on the lookout for them.

But wait, there’s more…

We also wanted to mention a couple of additional types of asbestos, as these come up every now and then. Although rarer than the big 5, we still come across them…and it’s important to know:

Asbestos Siding

Many houses still have asbestos siding on their exteriors. Asbestos siding was very popular product back in the 1950s and 1960s.

Asbestos Siding

This type of siding should to be painted every 5 to 7 years, so it’s not a maintenance-free material like vinyl siding. Asbestos siding is very fragile in nature. If a tree branch falls on it, or a baseball occasionally hits the wall, it might crack the asbestos siding panel, and it is going to be hard to find new siding piece to replace it.

As long as it’s not disturbed, it can stay on the exterior of the home for a long period of time. However, care should be observed when removing or replacing of siding occurs, or consult a professional contractor.

Asbestos Siding Easily Cracks

Asbestos Siding Easily Cracks

Gravity Furnace

Often nicknamed an ‘octopus’ furnace because of its multiple “arms” they date back to the late 1800s and early 1900s. They were originally designed to burn coal, but later switched to burn oil or natural gas. There aren’t too many left, but you still sometimes find them in older homes, especially where the owners have lived there for many decades.

Although they are only about 50% energy efficient and take up huge amounts of space, older homeowners often don’t replace them because, like the Energizer Bunny, they just keep going and going.… with few moving parts, and there just isn’t much that can break down. As its name implies, air circulation in a gravity furnace relies on gravity… the principle: that warm air rises and cool air falls.

There is no fan on a gravity furnace. That is why there are so many “arms” and why they are so large. Since no fan is pushing the air, the air pressure is lower as the warm air gently enters the room and there tends to be fewer hot spots.

However, there is no way to provide central air conditioning or warm air to the basement with this type of furnace, and there is no filter since that obstructs air movement. Additionally, almost all gravity furnace systems are insulated with asbestos. We have only seen a half dozen of these, but they are still out there.

Asbestos Shingles

Asbestos shingle history begins with inventor and entrepreneur Ludwig Hatschek who was born in the Czech Republic in 1856. In 1904 two production lines were rolling with a product range of roofing slates, honeycomb slates, and facade cladding.

They conquered the markets, and by 1911 the production was running at full capacity and products were being exported to Africa, Asia, and South America. Manufactured from a mix of asbestos fibers and hydraulic cement, asbestos-cement roof shingles were rigid, durable and fireproof.

Asbestos Shingles

They would not warp or rot and were resistant to damage caused by insects. Shingles made of slate or clay were most popular at the turn of the 20th century. Asbestos roof shingles came on the scene and were instantly attractive, being much lighter and less expensive. Once it was discovered that colored pigments could be mixed to create a choice of color, the appeal of the product exploded.

Luckily, because of their location, it is extremely rare to see these shingles still in use today. If you do, the house likely has bigger problems than this such as roof leaks and water damage below the roof. However, this is just another great example of how prominent asbestos was in building material.


As you can see, asbestos has reached far and wide in residential construction over the past decade. The chances of coming across it when buying an older home are still high today. It is something to consider when purchasing older houses with remodeling in mind. Fortunately, most inspectors are trained to identify and call out these items during your pre-purchase inspection. We can also test the material to determine if it needs proper mitigation during removal

Asbestos is one of many harmful items that people installed in homes in the past. We hope this summary will help you identify asbestos-related concerns and resolutions when purchasing or renovating your home.

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About the Author: Chris Scott

Chris Scott is an ASHI certified home inspector with multiple years of experience in home inspections, blower door testing, duct leakage testing, and Boulder Rental License Inspections. Chris is also the Website Coordinator for Scott Home Inspection.

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