Do You Know What Type of Insulation Is in Your Attic?

Many homeowners are experts on their kitchens and living rooms, but when it comes to the attic, it’s often a “don’t ask, don’t tell” situation.

The attic is a mysterious place—a dusty frontier where homeowners rarely venture. But if you do take the plunge and peek through that hatch, what you find there matters more than you might think.

At Mose Home Inspection, we believe your insulation is the “blanket” that keeps your home comfortable and your energy bills manageable. Knowing which type you have is essential, especially if you’re living in one of the many older homes with unique quirks found across Montreal.

Here’s a breakdown of the most common types of insulation and what you need to know about each.

1. Fiberglass: The “Pink Panther” Classic

Fiberglass is the most recognizable insulation, usually coming in those famous pink soft batts (though it can be yellow or white). Because glass is a poor conductor of heat, it’s great at stopping thermal transfer.

  • The Pros: It’s been used for decades, it’s relatively affordable, and it often contains up to 30% recycled content.
  • The Cons: It loses its R-value (insulating power) if it gets compressed or wet. It can also be an irritant to the skin and lungs if handled without proper protective gear.

2. Mineral Wool: The Heavyweight Competitor

Mineral wool is often a superior choice to fiberglass. It’s significantly denser, which makes it excellent for soundproofing as well as heat retention.

  • The Pros: It’s fire-resistant, doesn’t absorb moisture (so mold isn’t a fan), and can actually improve indoor air quality by trapping dust particles. It’s also made of up to 70% recycled material.

The Cons: It’s more expensive than fiberglass and can be harder to find in some local hardware stores.

3. Vermiculite: The Historical Red Flag

Common in homes built between the 1920s and 1970s, vermiculite looks like small, shiny silver-gold or grayish-brown pebbles. When heated, it “puffs up” to create air pockets.

  • The Big Risk: The issue isn’t the mineral itself, but the fact that about half of vermiculite sold in North America was contaminated with asbestos.
  • What to Do: If you find this in your attic, don’t disturb it. Have it tested by a professional immediately to see if asbestos is present.

4. Cellulose: The Eco-Friendly Choice

Made from about 80% recycled newsprint, cellulose is a favorite for those looking for an ecological option.

  • The Pros: In cold climates like ours, cellulose performs better than fiberglass, which can lose half its insulating power when the temperature drops. Because it’s blown in, it fills every tiny gap and crack, acting as a great air blocker.

The Cons: It can be more expensive than basic fiberglass batts and can settle over time, potentially reducing its effectiveness.

5. Spray Foam: The Ultimate Shield

Spray foam offers the highest R-value per inch, making it the “gold standard” for cold-climate homes.

  • The Pros: It expands to fill every nook and cranny, creating a perfect air barrier. It’s the best way to prevent heat loss in a leaky attic.
  • The Cons: It’s the most expensive option on the market and requires professional installation. This is definitely not a DIY project for a Saturday afternoon.

Don’t Let Your Attic Be a Negotiating Surprise

One of the most common reasons a home sale hits a snag is a “surprise” found in the attic during the inspection. Whether it’s outdated insulation, signs of mold, or hidden vermiculite, finding out at the last minute can lead to anger, disappointment, and lost deals.

Avoid the stress with a pre-sale inspection. Our comprehensive Mose Report gives you a full picture of your home’s health, from the foundation to the highest point of your roof.

and know exactly what’s over your head.

Frequently Asked Questions (FAQ)

R-value measures a material’s resistance to heat flow. The higher the R-value, the better the material is at insulating your home. In Montreal, having a high R-value in the attic is critical for saving on heating costs.

Yes, it is common to “top up” older insulation with a new layer (like blowing cellulose over old fiberglass). However, you should never cover vermiculite with new insulation, as this makes future removal much more difficult and expensive.

If your home is drafty, your energy bills are spiking, or you see signs of moisture or animal nesting in the attic, it’s time for an assessment. An inspection can tell you if you just need a “top up” or a full replacement.

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