Asbestos is a type of naturally-occurring mineral with a contentious legacy. 

Once called a “miracle mineral,” asbestos was prized for its versatility and unique characteristics. Strong, durable, and capable of withstanding the elements, asbestos had near-unprecedented application. Compared to other industrial ores, it had the added advantage of being both inexpensive and widespread. 

During its heyday, asbestos was used to fabricate a wide range of construction materials, from vinyl floor tiles to cigarette filters. 

Today, we know that asbestos is anything but safe. However, despite the United States’ decades-long campaign against the asbestos industry, contamination remains a common source of concern. Asbestos-based products can still be found in tens of millions of homes, posing a potentially insurmountable challenge to public safety and individual well-being. 

While some non-friable asbestos-containing materials, like siding, present little risk to prudent professionals, homeowners must nonetheless exercise significant caution when renovating or remodeling asbestos-affected properties. 

Asbestos and the Construction Industry

People around the world have worked with asbestos since time immemorial. 

However, for a great many centuries, asbestos was scarcely more than a novelty—an unusual, novel substance that could be woven into fireproof cloth to entertain visitors. 

During the Industrial Revolution, though, asbestos finally realized its potential. Confronted by surging demand for affordable urban housing, property developers turned to asbestos to construct fire-resistant homes and tenements. 

Asbestos Construction Products

Between the late 19th century and the end of the 20th, asbestos was baked into a variety of products, including, but not limited to, the following: 

  • Adhesives 
  • Attic and wall insulation
  • Automotive parts
  • Boiler ducts 
  • Clutch linings
  • Concrete shingles 
  • Furnaces
  • Heat-resistant fabric 
  • Gaskets
  • Military supplies
  • Roofing materials 
  • Textured paint and patching compounds 

Asbestos siding was also used in the construction of many buildings. 

However, asbestos-based siding materials came in several different forms, not all of which are easily identifiable. 

Asbestos Siding

The federal government recommends that homeowners and employers presume that asbestos is present in any structure built during or before the 1980s. 

In the United States, asbestos production peaked between the late 1960s and the late 1970s. During and throughout this same period, the use of asbestos-cement shingles and asbestos siding remained prevalent. 

While some siding products—like natural stone—rarely, if ever, contain asbestos, other types could be contaminated.

Common asbestos-contaminated siding materials include, but are not limited to, the following: 

Stucco Siding

Stucco is a cement-like substance that is typically comprised of aggregates, a bonding agent, and water. Most modern stucco does not contain asbestos. However, some historical applications of stucco-type siding integrated asbestos for its fire-retardant properties. 

Natural Wood Siding

Natural, non-synthetic wood does not contain asbestos, but many natural wood siding materials are underlain by reinforcing asbestos-based products. These products could include adhesives, paints, and insulation. 

Asbestos Lumber Siding

Asbestos lumber siding, sometimes called asbestos cement sheathing, was used to create different types of synthetic siding, such as false brick siding and false wood siding. 

Vinyl Siding

Asbestos has been used in a variety of vinyl-containing products, notably vinyl floor tiles. While asbestos-based vinyl siding is relatively rare, any vinyl product fabricated before the 1980s could contain asbestos. 

How to Identify Asbestos Siding

Asbestos exposure is associated with a wide range of serious and potentially life-threatening medical conditions, up to and including cancer.

Since no level of asbestos exposure can be considered safe, property owners who believe their home could contain asbestos often go to great lengths to minimize the potential threat to themselves and their families. 

However, asbestos-containing siding materials come in a variety of forms—very few of which are easily distinguishable from their non-asbestos containing counterparts. 

Astute or experienced homeowners might be able to gauge whether a product is likely to contain asbestos by assessing the following: 

  • The product’s age. Siding that was fabricated, or installed, during or before the 1980s is much more likely to contain asbestos than comparatively modern siding. 
  • The product’s appearance. Some asbestos-based products crumble with age. If an asbestos-containing product has crumbled, or become friable, then small asbestos fibers could be visible around the damaged area. 
  • The product’s location. State and federal health regulators do not always recommend removing asbestos siding. Consequently, many construction companies will simply place newer siding over older, asbestos-contaminated siding. If you are remodeling and find an aged layer of siding underneath a more modern product, it could contain asbestos. 

Unfortunately, even trained professionals cannot always identify asbestos-containing materials without first testing for asbestos or requesting a comprehensive asbestos audit.

Friability and the Risks of Asbestos-based Siding

Asbestos-contaminated siding does not always need to be removed. Although asbestos is a potent carcinogen, it is relatively harmless when it is left both inaccessible and undisturbed. 

According to the Minnesota Department of Health, for instance, “siding that [contains] asbestos, when intact and in good condition, [is] generally nonfriable and […] not hazardous.” 

However, over the course of many years, non-friable asbestos-containing siding can be degraded by continued exposure to the elements. It can also be damaged by fire, or through the stresses of routine maintenance and home renovation. 

Friable asbestos poses a far more immediate health concern, insofar as friable asbestos can easily aerosolize. Asbestos fibers that have aerosolized are microscopic, invisible, and odorless. These fibers pose a significant and often-undetectable inhalation risk. 

Once inside the body, they can become trapped inside the respiratory system, causing inflammation, scarring, and the abnormal cellular growth characteristic of cancer. 

Removing Asbestos-Contaminated Siding from an Older Home

Homeowners who believe that contaminated siding presents a risk should consider asbestos abatement, or removal. 

Asbestos abatement procedures can vary between companies, but most abatement professionals mitigate asbestos-related threats by implementing either, or both, of the following measures: 

  • Encapsulation. 

Encapsulation is a cost-effective alternative to removal. If an asbestos abatement professional recommends encapsulation, they may coat the asbestos-contaminated material with a special sealant or surfactant. This sealant creates an adhesive matrix, which prevents asbestos fibers from aerosolizing or otherwise spreading. 

  • Removal. 

Asbestos removal is the physical removal of all asbestos-containing materials, whether from an individual item, a room, or an entire house. Removal can be time-consuming and expensive, but it is often the only way to eradicate asbestos exposure risks in their entirety.  Asbestos removal should always be overseen by a certified asbestos abatement company. While few jurisdictions prohibit private parties from conducting asbestos abatement work without professional oversight, many cities and states actively enforce legislation regulating the safe disposal of asbestos.