How Much Does Mineral Wool Insulation Cost? [Materials And Installation]

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Quality home insulation is essential to maintain a comfortable home. Of course, if you want quality insulation, it's going to cost you a decent amount - especially if it's mineral wool! How much would it cost to install this type of material? If that's what you're wondering, let's run over some numbers!

There are many factors to consider regarding how much mineral wool installation will cost. The areas you need to cover, R-value required, and labor costs are some factors to consider.

In general, mineral wool insulation will run you about $0.62-$1.10 per square foot. Including labor costs and installation, it will cost around $2,200-$5,900 to insulate a 1000 square foot area.

If you want to get an idea of what range you'd fall near, it's essential to go over every little detail. It'll mostly depend on where you're planning to install the material. The R-value requirement will also play a factor in cost. Will it be worth the money? We discuss this and more further ahead.

Caucasian Construction Worker with Roll of Insulating Material, Floor Insulating by Mineral Wool, How Much Does Mineral Wool Insulation Cost? [Materials And Installation]

Factors to Consider

Work composed of mineral wool insulation in the floor

The first question you need to answer to determine how much you'll have to pay out of pocket is - where are you installing it? Will it be the roof, walls, or garage? The area matters because there's a standard R-value you'd need to meet.

For example, exterior walls will need an R-value of around R-13 to R-23. On the other hand, attics can require anywhere from R-30 to R-49. Additionally, floors will need an R-value of R-13 to R-30. It all depends on the climate zone you live in.

That begs the question, what are the areas where you can typically install mineral wool? As some suggest, you can use mineral wool to insulate any area - like the walls, attic, ceilings, and floors.

In this case, where you install mineral wool will determine the final cost. Insulating attics will cost more because it requires a higher R-value. Meaning, you'll need thicker batts or more blown-in mineral wool to meet the standard. Walls will require less.

The region you live in also factors into the final cost. If you live in a humid climate, you'll need less insulation material. On the other hand, if you live in cold conditions - like regions 5 and 6 - you'll need more.

Preparations

Electrician working with wires at attic renovation site

Before you install the mineral wool, are there any preparations you'll need to make? Perhaps you need to remove the current insulation you have. If this is the case, you'll need to pay around $1 to $2 per square foot to have it removed.

You can cut on this expense by doing it yourself. However, if there's serious damage to the area, it'd be best if you left removal for the professionals.

Though, in most cases, you wouldn't need to remove existing insulation. Instead, it's advisable to top up or mix different kinds of insulation to meet R-value requirements.

You'd only need to remove old insulation if there's any mold infestation or damage from pests. Pests can also leave urine and droppings that are hazardous for your home.

As you remove some insulation, you might find that the wiring needs fixing. If you need to hire an electrician to work on your wiring, it will generally cost around $50 to $100 per hour.

Labor

Construction workers reviewing blueprint at construction site

Of course, you're going to need someone to install the insulation. You cut costs by doing the job yourself. But, if you're not comfortable working with insulation material, hiring a professional to do the installation will cost $200-$500. In general, you can expect to pay contractors around $40-$70 per hour.

Thus, the area you need to fill in is crucial because - the longer it takes to insulate, the more you'll pay for labor.

Using Online Calculators

Of course, since we don't live in the same conditions, you can go online and use an installation calculator to estimate how much you'll need to spend.

If you want more accuracy, it's better to call up a local contractor and get an estimate. Regardless of the situation, you can expect it to cost thousands if you need to fill in more than 500 square feet of area.

Is Mineral Wool a Good Insulator?

With how much mineral wool costs per square foot, you might question if it's a good deal. Of course, the main factor that we're considering is the R-value of the material. In other words, we're looking for a good insulator. 

Can mineral wool fit in that category? To determine that, we'll have to put them up with other types of insulation material. In general, the R-value of mineral wool will range between 3.7 and 4.2 per inch of thickness.

Thus, it begs the question, how does it stack against other insulation types? Let's compare!

Cellulose

A 2x4 cavity filled with cellulose has an R-value of 13. Per square inch, cellulose offers an R-value of 3.2-3.8.

Fiberglass

Fiberglass has three choices of installation. There's blown-in, rolls, and batts.

Blown-in offers an R-value of 2.2-2.7 per square inch. Batts and rolls have an R-value of 4.3 per inch.

Spray Foam

Lastly, the other choice of insulation is spray foam. Many would consider it one of the best insulation materials you can get. Depending on the type you install, its R-value can range from 3.8 to 7.0 per inch.

As we can see, mineral wool stacks up well in terms of R-value. It performs within the ranges of spray foam insulation. Since it tends to have a higher R-value than other options, you could say that mineral wool is one of the best insulators you can purchase.

Does that mean you should only consider mineral wool and spray foam insulation for your home? Of course not! It all depends on your budget and needs.

Do You Need a Vapor Barrier With Mineral Wool Insulation?

A close-up of roof mineral wool, glass wool insulation over a vapor barrier, membrane between the wooden ceiling joists

Even if mineral wool holds water-resistant properties, there's still a chance it can get saturated with water. Although it won't hurt the mineral wool itself, it can increase the risk of damaging the surrounding area.

So, it begs the question, will a vapor barrier be necessary? In other words, should you pair it with mineral wool? They're an essential element in building construction. It prevents water vapor from reaching internal areas - where it can condense and promote rot or mold growth.

In theory, mineral wool itself can act as a vapor barrier for two reasons:

  1. It has water-resistance properties that won't allow moisture to seep in.
  2. Basalt and steel slag are inorganic materials. Thus, it won't be a food source for mold.

So, as some would suggest, you wouldn't need an additional vapor barrier for protection.

In practice, the type of insulation material isn't what determines if you need a vapor barrier.

It will depend on your climate zone. You won't need a vapor barrier if you live in climate zones 1-4. However, if you live in zone 4 (marine), you will need a class III vapor barrier. In these zones, the type of insulation you use won't matter. The reason is that these regions are very humid climates.

Zones 5-7 will also need a class II or III vapor barrier. You will need to install them on the interior surface of insulation in insulated wall and floor assemblies.

Does Mineral Wool Insulation Mold?

A panoramic image of a typical attic which has dangerous mould growing.

Mineral wool has water-resistant properties that prevent moisture from seeping into the material. However, accidents can occur. In some cases, mineral wool can become inundated with water. And, if you don't act quickly, you're facing a higher risk of mold growth.

But, would mold grow on the insulation material itself?

Not at all. However, there is a chance that it can grow inside mineral wool. But, it's only under certain conditions. The two essentials that mold needs for growth are moisture and food. So, why can't mineral wool be the food source?

Mineral wool is made of basalt and steel slag - both are inorganic materials. Thus, the mineral wool can't be a food source for the mold as it needs organic food to grow.

Rockwool - a mineral wool manufacturer - claims mineral wool can pass standardized tests with no signs of fungal growth.

Does that mean there won't ever be mold growth within mineral wool insulation? That would depend on what's going on near the material. If organic material gathers inside the mineral wool, it can mold - it just wouldn't be the mineral wool's fault.

How Long Does Mineral Wool Insulation Last?

Mineral wool is rated to last as long as your home stands. It's made of inorganic material that won't deteriorate or corrode. That is, of course, if you give it the perfect conditions. We all know how hard it is to keep consistency. So, while it is a general measure, it probably won't last that long.

In that case, the lifespan of mineral wool insulation depends on the person installing it and the environment. Still, mineral wool has a lot of qualities that make it able to last longer than other types of insulation material.

It's a non-combustible material with a high melting point. Thus, it makes mineral wool a highly fire-resistant material. Mineral wool also has hydrophobic properties that won't allow water to penetrate easily. Mold? As mentioned, it's an inorganic material.

Therefore, you'll only have to worry about the surrounding material for mold. All in all, it almost sounds like an indestructible material. However, things can happen. So, you can't count out having to replace it.

Final Takeaway

There are a lot of factors to consider when you need to install new insulation. Information online can only give you an idea. If you want a better estimate, call your local contractors to see what you can work with.

Before you go, you might want to check out these posts:

How To Install Mineral Wool Insulation In Ceiling [A Complete Guide]

How To Insulate Foundation Walls

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