What is Mineral Wool Insulation?

Mineral wool insulation is also known as rock wool. As mentioned above, the insulation is made from volcanic rock and slag, which is a by-product of steel production.

How is Mineral Wool Insulation Made?

It takes a couple of steps to make mineral wool insulation. First, the basalt and slag are melted in 3,000° Fahrenheit heat. Next, the liquid is exposed to air and spun into long fiber strands. These strands are then compacted into thick mats and cut into pieces for insulation. The pieces are called batts.

Stats on Mineral Wool Insulation

When you’re looking at insulation, most likely, you’re considering a few different factors. Here are some areas you might look at:

• R-Value
• Size
• Sustainability
• Cost
• Density

Let’s take a look at how mineral wool rates in each of these areas.

R-Value

Insulation’s ability to resist heat is measured by something called R-value. Insulation that has a higher R-value provides greater insulation. Mineral wool has an R-value of 3.0 to 3.3 per inch. This is slightly better than fiberglass.

Size

Since mineral wool insulation isn’t as widely used as fiberglass, there aren’t as many choices when it comes to size. Mineral wool is typically only available in a couple of sizes. The good news is, it’s very easy to cut.

Sustainability

Another benefit of mineral wool insulation is that it’s made from 70% or more of recycled material. This is a big deal for many in the world as businesses try to go greener. Fiberglass, on the other hand, is generally made up of 20 to 30% recycled materials.

Cost

Mineral wool insulation does cost more than fiberglass because it’s just not as readily available. Mineral wool is anywhere from 25 to 50% more than fiberglass. Remember, though, that you get the added benefit of better insulation from mineral wool.

Density

When you’re buying insulation, you also want to consider the density of the insulation. The denser a material is, the better it insulates against outside noise. Mineral wool has a density of 1.7 pounds per cubic foot, whereas fiberglass has a density of .5 to 1.0.

As you can see, mineral wool insulation offers many benefits over the standard fiberglass, even if it costs a bit more.

Is Mineral Wool Fire Resistant?

Another benefit of mineral wool insulation is that it’s fire-resistant. All insulation has to pass some level of fire resistance, but mineral wool is very fire resistant. In fact, it’s probably one of the most fire-resistant types of insulation.

Mineral wool insulation can withstand heat in excess of 1,800° Fahrenheit. This compares to fiberglass being able to withstand heat up to 1,000°Fahrenheit. This makes mineral wool insulation a safer choice when it comes to fire resistance.