Until recently, I’d heard about asbestos and how dangerous it was, but only in relation to popcorn ceilings. I had no idea it actually used to be an incredibly common component in numerous building products and materials.
Asbestos is an incredibly durable, versatile material that made things stronger and safer—at least it does if you overlook the fact that we now know it causes incurable harm to the lungs. If you read on, I explain what exactly made it so useful and how we used to utilize those qualities.
Asbestos is strong, lightweight, inexpensive, malleable, nonconductive, insoluble in water, and resistant to fire, heat, biological breakdown, and chemical breakdown. All of these qualities make it a near-perfect construction material.
What Is Asbestos?
Asbestos is actually an umbrella term for a group of six fibrous, naturally-occurring minerals that all share extremely similar properties. They are separated into two groups—serpentine and amphibole.
Serpentine asbestos has long, curly, flexible fibers that allow it to be used in many different ways. Chrysotile asbestos is the only type to fall into this category, and is also the most commonly used type of asbestos.
Amphibole asbestos is straight and stiff, with sharp needle-like fibers. This category contains the five remaining types of asbestos: actinolite, amosite, anthophyllite, crocidolite, and tremolite.
While it was not able to be used in as many ways as serpentine asbestos, amphibole asbestos was still used in many construction and manufacturing materials because of the shared qualities between the two groups.
Unfortunately, the harmful effects of asbestos were only discovered decades after it came into common use. This is because it also takes decades for the health issues caused by asbestos to develop, despite their severity.
Desirable Qualities for the Building Industry
As discussed, there are several types of asbestos, and all of them contain numerous qualities that made them desirable in building, manufacturing, and construction industries. It’s not an exaggeration to say asbestos had hundreds of different uses.
- Strong (durable)
- Inexpensive (it can be used in it’s natural form, so there is little cost of production)
- Resistant to chemical breakdown
- Resistant to biological breakdown
- Insoluble in water
How and Why Asbestos Was Used in Construction
Asbestos was considered a great material for insulation because of its strength, resistance to heat, and incombustibility. These qualities gave it a long lifespan, durability, and of course, the heat resistance needed to insulate.
Since asbestos is also non-soluble and water resistant, it was also a great material for anywhere water was involved, such as for boilers or pipes.
Asbestos insulation came in many forms. This includes four types of wall and attic insulation, including blanket, block, loose-fill, and spray-on insulation.
Asbestos-cement millboards, corrugated sheet insulation, in-duct liners, and pipe lagging are just some of the other types of insulation that often contained asbestos in the past.
Surprisingly enough, asbestos wasn’t just used for heat or water insulation, but also in sound insulation. It was often added to acoustic boards to increase their durability.
Chrysotile asbestos, a serpentine asbestos, is the most common type of asbestos used in any type of construction, As such, it can of course be found in insulation.
However, it would not be uncommon to find any of the five amphibole asbestos in insulation products as well.
When it came to tiles, asbestos was an incredibly popular addition for its strength and heat resistance.
Vinyl and linoleum flooring tiles were often made with asbestos to increase their strength, allowing them to be used in high-traffic areas that would normally be subjected to heavy wear and tear.
Floor tiles were not the only type of tile to contain asbestos. Roofing tiles also benefited from its strength and durability.
Furthermore, asbestos was often used in the adhesives that were used to attach ceiling tiles to each other or otherwise hold them in place.
Regardless of location or type of tiling, the addition of asbestos was also popular because it made more portions of the home fireproof in the event that a fire should start.
Since asbestos is such a cheap material, it was an extremely cost-effective way to fireproof materials, but we’ll discuss more in a later section.
Once again, the serpentine asbestos chrysotile would be the most common type of asbestos one would find in tiles, but amosite and tremolite were also commonly used.
Cement and Plaster
It was very common to find asbestos used in cement and plaster, once again thanks to its durability.
Both cement and plaster are often used in manners that require a flat surface and smooth application. The addition of asbestos reinforced these materials, making them less likely to crack from shrinkage during the drying process.
Because of its water resistance and small fibers, it also reduced the permeability of these mixtures and made them more water resistant.
Additionally, asbestos is comparatively lightweight despite its high durability. By adding it to cement, it kept the weigh down while still adding strength. This reduced weight is valued in construction, allowing many tasks to be completed with less concern for maximum weight.
Chrysotile was the most popularly used asbestos for this purpose, though crocidolite asbestos was sometimes added as well.
Drywall and House Siding
Drywalling involves securing many large sheets of drywall panels, then “mudding” or attaching these panels together with a spreadable material called joint compound.
It was extremely common to find asbestos in joint compound, though it could often be found in the panels themselves.
Asbestos kept these materials light while increasing their strength, making it easier to manipulate and install them.
The same concept applied to house siding, which was often made from sheets of asbestos-cement pressed into thin boards.
Asbestos made house siding far lighter and more durable, making installation easier. Because it is also resistant to water, electricity, pests, and corrosion, it increased the lifespan of these materials, which would be exposed to the elements.
For both drywall and house siding, adding asbestos also increased their fire resistance. This was great for containing potential house fires and minimizing damage.
Chrysotile asbestos was the most commonly used, although any of the five amphibole asbestos types may be found in drywall or siding materials as well.
Popcorn ceilings were incredibly popular during the time period that asbestos was being used. This means that many popcorn ceilings built at that time also contain asbestos.
These ceilings were popular for their ability to hide imperfections in and to reduce noise for the residents who would move into the building.
Now, popcorn ceilings are made from plaster and, as we already covered, plaster often used to contain asbestos for its benefits in strengthening the material and in reducing the likelihood of cracking while it dried.
While tiny fibers of the asbestos may have flaked off when the ceiling was disturbed (unless it was painted over), the actual plaster itself was stronger and the popcorn was less likely to break off whenever something was to hit the ceiling.
To conclude, the addition of asbestos made popcorn ceilings more sound resistant, fire resistant, and durable all at once.
As covered, chrysotile asbestos is the most likely to be found in plaster, although crocidolite asbestos may also be.
I’ve mentioned several times already that asbestos was often used for making materials more fire resistant due to its nonflammability and incombustibility.
For this reason, it was used in just about every type of construction material you can think of. Cement, adhesives, insulation, and plaster are just some, as you now know. Indoors, outdoors, or within the walls, asbestos could be found everywhere in the home.
However, it was also used to fireproof or insulate many home goods like ironing board covers, and even appliances like ovens, toasters, and hair dryers.
As per usual, chrysotile is the most likely type of asbestos to be found in any of these materials, due to its abundance and higher versatility compared to other types of asbestos.
Speaking of versatility, chrysotile asbestos’ unique flexibility and structure allowed it to be woven into fabrics.
This was primarily done (yet again!) for the fireproofing qualities of asbestos. It was used in the manufacturing of fire blankets for use at home or by the fire department.
Asbestos was also woven into the wicks of candles, gas ranges, and oil lamps to increase their lifespan.
Kitchen towels, hot pads, placemats, and oven mitts contained asbestos in order to increase their heat resistance and increase their quality/ability to perform.
Asbestos-containing fabric was even used in electric blankets, to better insulate them and reduce the risk of surrounding materials catching fire.
As we already know, asbestos could be found in pretty much every area of construction, in almost every material, and roofing products like sealants were no exception.
Asbestos had at one point been added to caulk, roofing tar, mastic, and even roof flashing. It was a cheap, strong addition to these various sealants and adhesives that strengthened the bond between various roof components while adding waterproofing and fire resistance.
As mentioned previously, asbestos is also an extremely lightweight material. This is particularly important in roofing.
While some roofing components need to be heavy to be secure, there is an upper limit; too much weight can weaken the structural integrity of your home if it wasn’t built to handle such a heavy upper load.