This Is Why Popcorn Ceilings Crack (Facts & Precautions)

Popcorn/stucco ceilings have been used in buildings since the early 1950s. A spray-on mixture covers ceilings in bumps which gave popcorn ceilings their nickname. The mixture is simple to apply, covering existing blemishes like dampness, leaks, and cracks. It also dampens external sounds of the street, traffic, and human noises that originate nearby. 

popcorn ceiling

Two significant contributors to crack in popcorn ceiling are natural wear-and-tear and damage caused by moisture. Old buildings show structural weaknesses, causing the stucco layer to sag and, eventually, crack. Moisture also weakens the ceiling’s dry mixture, which may cause it to crack. 

Having cracks on one’s ceiling is not an unusual occurrence, especially in older buildings. Popcorn/stucco ceilings are incredibly brittle and may contain some hazardous chemical components. Let’s consider the warning signs known as popcorn ceiling cracks and the reasons they appear on popcorn ceilings.

What Are Popcorn Ceilings Made Of?

Popcorn ceilings are made of tiny particles of one of two possible components. One is vermiculite, a natural mineral commonly used in buildings for heat and cold insulation and fire and sound protection. Vermiculite is also for gardening, where it acts as a sponge – retaining water and improving aeration.

The second component that may be used to create the popcorn ceilings is polystyrene, commonly used for packaging and thermal insulation in buildings, refrigerators, and large cold storage. Polystyrene is used in some popcorn ceiling mixtures as rigid foam due to its durability and resistance to water-based damage. 

Why Do Vermiculite And Polystyrene Crack?


Cracks may appear in popcorn ceilings for various reasons, such as humidity, which is caused as humid, warm air touches a cold surface. Some of one’s daily activities, such as cooking, heating the place, bathing, tumble-drying clothes, and washing dishes may add humidity to one’s home. 

Vermiculite and polystyrene present two peculiarities that contribute directly to the appearance of cracks in popcorn ceilings: vermiculite is friable, and polystyrene is brittle. Let’s take a closer look at these. 

Cracks In Friable And Non-Friable Materials

Materials are considered friable if, when they are dry, they crumble and eventually turn into powder under hand pressure. Non-friable materials will not crumble under slight pressure. Over time, and even under slight and indirect pressure, friable material will weaken and crack. 

Cracks In Brittle, Inflexible Materials 

Brittle materials are rigid and require more pressure before they break into pieces. However, they do not disintegrate quickly into powder, as friable materials do. However, brittle materials lack flexibility and, facing natural wear-and-tear or moisture, their peculiarities will trigger their deterioration. 

Are There Other Reasons For Popcorn Ceilings To Crack?

In addition to the type and character of the materials used to form the stucco layer, there are other – external – reasons for crack in popcorn ceilings, such as plumbing, seasonal behavior of infrastructure, and the effect of home appliances. 

Plumbing Deterioration May Cause Water Leaks

Plumbing fixtures running above the ceiling may leak and cause the stucco layer to sag, causing cracking and crumbling. If a room above the ceiling has a leaking bath or sink, these too may seep through. Water, and humidity, may increase the crumbling and cracking of the stucco layer.

Truss Uplifting May Shake The stucco layer  

During winter, wood trusses are exposed to moist air from above, while an airflow warms their bottom section due to the stucco layer. The heat causes the lower part of the truss to curve upwards. In summer, the curve straightens again. This up-and-down movement of the stucco layer makes it unstable and may cause cracks to appear. 

Everyday Appliances May Cause Noise And Vibrations

According to Engineering Consultancy and Research company EMOYS, the operation of some of our everyday home appliances may include electromagnetically-excited noise and vibrations.

These and other ongoing movements, tremors, vibrations, and shakings may cause friable materials to crumble, causing cracks in the process. Some non-friable materials may become friable under constant pressure, and brittle materials may crumble and crack over time. 

EMOYS’s list of large home appliances emitting electromagnetic excited noise and vibrations includes:

  • Refrigerators and stand-alone deep-freeze units
  • Washing machines and dryers
  • Heating units and water heaters
  • Ventilation and Air Conditioning (HVAC) units
  • Fluorescent, halogen, and LED lamps
  • Electrically heated cooking units

My Popcorn Ceiling Shows Some Small Cracks, Should I Worry?

popcorn ceiling crack

Since either vermiculite or polystyrene is likely to be present in the mixture that made up your ceiling, you should note that friable and brittle materials are not flexible. Even a small crack is like a flag that warns you that the ceiling may break up further. It is recommended to take a closer look at any ceiling crack wider than 1/8 inch. 

Shallow cracks affecting the outer layer are easier to fix than large deep cracks. The cracks you should be looking out for are wide, long, and sometimes jagged. They may crisscross your ceiling and extend through the stucco across the room and sometimes to other parts of the apartment. These cracks may be pointing to a more significant problem. 

What Is The Connection Between Popcorn Ceilings And Asbestos?

asbestos in popcorn ceiling

It is assumed that all popcorn ceilings put up before early-to-mid-1990s contain asbestos, a toxic mineral banned in the US during the 1970s. When popcorn ceilings deteriorate, asbestos-containing materials (ACM) break into fibers and, eventually, into toxic powder which may cause lung cancer over time.

How Did Asbestos Get Onto Popcorn Ceilings?

Popcorn ceilings were popular in the US between the 1940s and the 1990s. The two materials mainly used to create the stucco mixture, vermiculite, and polystyrene, contain asbestos, a heat-resistant mineral with solid fibers. Over the years, asbestos has been widely used for insulation and fire resistance in buildings.

Asbestos was declared a hazardous air pollutant under the Clean Air Act of 1970 and was officially banned three years later. Some asbestos-containing products manufactured before the ban continued to be installed in buildings until the 1990s. Generally speaking, popcorn ceilings in buildings constructed before the late 1990s may contain asbestos.

Does The Presence Of Asbestos Make A Popcorn Ceilings Toxic?

According to asbestos testing facility JSE Labs, between 1 and 10 percent of asbestos are present in popcorn ceilings. While one is advised to keep an eye on the bubbly layer, it should be noted that, as long as it is intact, asbestos is not dangerous.

The best way to test your popcorn ceiling for asbestos is to gently scrape a bit of the stucco layer, put it in a plastic back, and refer it to an EPA-Accredited lab for testing. The lab may collect the sample from you, or you can take it to the lab yourself. Usually, results will be available from the lab two weeks after it receives the sample. 


Popcorn ceilings are especially prone to damage due to the friable and brittle nature of two components, at least one of which is present in the popcorn, or stucco, mixture. Vermiculite and polystyrene may become unstable under pressure, structural damage, seasonal temperature changes, humidity, vibrations, or noise. 

The presence of asbestos in old installations of popcorn ceilings increases the risk of toxic exposure. Still, most experts agree that asbestos is not harmful if it is left untouched. This means that home and building owners can maintain the existing pre-1990 popcorn ceiling installations, even though they contain asbestos.

The appearance of small hairline cracks is usually seen as “cosmetic damage” – superficial damage that does not require significant scrutiny or maintenance. Large cracks, especially if they are larger 1/8 inch and stretch diagonally across the ceiling or a multitude of cracks, are considered an occurrence that requires a close, preferably professional, look. 

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Barry Gray

Hi, I’m Barry. I’ve loved woodworking and bringing things back to life for more years than I care to remember. I hope my passion for tools comes across loud and clear in everything you read here on The Tool Square.