The Downside Of Old Insulation

Before the introduction of building codes, there was no information on the safest and most energy-efficient materials to use for insulation. Consequently, old types of insulation are not as efficient as today’s insulation, and some may be hazardous to your health.

If you live in an older home, knowing the type of insulation installed in your home can help you understand the risks associated with your insulation and whether it is efficient enough to serve your home. Read on to learn more about the common types of old insulation in older homes.

3 Main Types of Old Attic Insulation

If you’re considering renovating an older home, consider starting with the insulation. You may find that your old attic insulation is too damaged or consists of materials that are not as efficient as modern insulation. Common materials used in old insulation include:

  • Vermiculite
  • Fiberglass
  • Mineral wool


Vermiculite was a popular insulation material back in the day due to its easy application. Builders would pour vermiculite between joists in an attic to insulate a house. If your home has this type of insulation, you may identify it by its shiny, gravelly look.

Vermiculite is naturally absorbent and fire-resistant and has good insulation properties. This type of insulation is not hazardous. But, before 1990, most vermiculite used in America came from a mine that also contained asbestos deposits.

Avoid handling your vermiculite insulation if there is a possibility it may have asbestos contamination. Call in a certified insulation contractor who can safely remove and replace contaminated insulation.


Building contractors still use fiberglass for insulation today. Insulation contractors install this insulation material in a finely spun form, which they roll on the walls as batting, or in a loose form, which they spray into walls. The material insulates the house by trapping air inside its pockets. Therefore, it loses effectiveness when compressed. Loose fiberglass filling may also shed with time.

Although fiberglass has no known health hazards, you must wear protective gear when handling it because contact with broken fiberglass pieces may cause skin and throat irritation. A professional insulation contractor will have protective gear like gloves, goggles, and a dust mask for handling fiberglass.

Mineral Wool

Mineral wool is a common insulation material in houses built before the 1940s. You may find mineral wool insulation in the form of rock wool or slag wool. Rock wool is a product of spun molten rock intertwined to look like cotton. Slag wool is a product of waste material from molten metal ore.

Insulation contractors install mineral wool as batts, loose fill, blankets, or boards that provide sound and heat insulation. Mineral wool has no health hazards. However, contact with mineral wool can irritate the skin and respiratory system. You must wear protective gear when handling the material.

Signs of Asbestos Contamination

If your old attic insulation has asbestos on it, your and your family’s health may be at risk. Some health effects of asbestos exposure include asbestosis, a higher risk of throat, kidney, lung, and esophageal cancers, and mesothelioma.

Some signs of asbestos contamination in old types of attic insulation include:

  • Insulation that lays flat
  • Gray-brown or silver-gold coloring in insulation particles
  • A texture that feels like accordion pleats in insulation particles

How to Choose the Right Insulation for You

The best type of insulation has gone through rigorous safety and quality checks. Fiberglass, spray foam, blown-in cellulose, and mineral wool are among the most highly tested insulation types used today.

Fiberglass and cellulose are eco-friendly and cost-effective insulation materials. But cellulose, made from recycled newspapers, is a fire hazard. On the other hand, mineral wool and spray foam are more expensive but have an excellent thermal resistance.


The only sure way to know whether an insulation material will give you the service you need is to consult an experienced insulation contractor who has worked with various brands and insulation types. At Insulation Co., we pride ourselves on our extensive experience in the insulation industry.

Reach out to us today to discuss insulation choices, and get the best insulation installation services in Washington state.

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