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  • Writer's pictureCameron Home Inspections

PACMs (Asbestos!): Common in Many Homes

Updated: Jan 3, 2023

PACMs, or Presumed Asbestos Containing Materials, can be found throughout millions of homes across the country. The term "Presumed" is used because the definitive way to confirm asbestos in a building material is to collect a sample and have it analyzed in a laboratory. That said, many common products installed until about 1980 are known to contain practice is to presume the identified material in fact does have the dangerous fibers within it and treat it carefully.

Asbestos danger removal, PACM

A group of naturally-occurring minerals are lumped into the term "asbestos." Their fibers are both strong and resistant to heat and corrosion which makes them a perfect choice for incorporating into various building materials.

However, when these sharp, needle-like fibers are inhaled, they can cause serious damage to the respiratory system. Both mesothelioma (a form of lung cancer) and asbestosis (a non-cancerous lung disease) have been connected to asbestos exposure. Dust that contains the fibers can be created when the material is disturbed - often during major renovations of older homes and especially when the material is friable, or easily broken or crumbled.

asbestos fibers,  Asbestos Microscopy
Courtesty: - History of Asbestos Microscopy


One of the most well known PACMs is vermiculite insulation. When exposed to extreme heat, this natural mineral will expand many times its original size and resemble a small, layered pebble. Vermiculite itself is not dangerous - the problem is, most of the vermiculite insulation produced throughout the 20th century was mined from an area that also had asbestos minerals. This means that the vermiculite was contaminated with asbestos and then distributed and installed throughout homes across the country.

Vinyl Floor Tile

Another common building material known to contain asbestos is older vinyl floor tiles, and the mastic used to attach them. This is particularly true in tiles that measure 9"x9", but is also common in 12" and 18" squares.

Duct Wrap Another material generally considered to contain asbestos can be found on your home's older HVAC ducting. This white-ish wrap (resembles paper or a thin fabric) is used to either seal ducting joints or can be found wrapped around the entire duct.

Siding and Roofing

Older cementitious siding commonly contains asbestos, as do some shingles and roof tiles. Like many other products, if these building materials begin to crack or break, they may release the harmful fibers.

Pipe and Flue Insulation

Various pipes or flues may be wrapped or coated in an insulating layer that contains asbestos. These areas are often fragile, if not already crumbling. Abandoned systems, (old boiler pipes in the example below) are sometimes disconnected and left in place due to the cost associated with safe demolition and removal.

Popcorn and Drop Ceilings

Popcorn texture was once a popular ceiling coating in which the material, often containing small pieces of vermiculite (which gives it its bumpy appearance) were sprayed onto ceilings. Various square or rectangular acoustic tiles on a drop ceiling can also contain asbestos.

Plaster, Gypsum, and Joint Compound

Older homes often have walls made of plaster which asbestos may have been added to. The same is true for early forms of drywall, often called "wallboard" or "gypsum board." This wall covering, as well as both the tape and compound used at joints, sometimes had asbestos added to it.


The above mentioned PACMs commonly found in older homes is not an exhaustive list as asbestos was used in numerous products for many decades, but it's a good start if you plan to conduct any renovations or are otherwise concerned that asbestos fibers could be disturbed in your home. Make sure to seek out a qualified Asbestos Abatement Contractor to avoid contamination in your home or health risks to your family. Do you know of any other PACMs not listed here? Have you had asbestos removal performed in your home? I'd love to hear your thoughts or experiences in the comments!

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-Jonathan ASHI #265859

*The views and opinions expressed in this blog are those of the author and do not necessarily reflect the official policy or position of any other agency, organization, employer or company.

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