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Finding the right insulator for your home is important. You want an insulator that is easy to install, has good thermal conductivity, has a high R-value is fire resistant, and is safe to handle. Mineral wool insulation is hardly a new product in the market. It has been around for decades, but somewhere along the way, it lost out on popularity.
While you have other alternatives, such as blown-in insulation and fiber batts, mineral wool is making a strong comeback thanks to its advantages over the other insulation materials. So if you’re building a new home or replacing the insulation in your current home, here is why mineral wool insulation is a great choice.
What is mineral wool insulation?
Broadly speaking, mineral wool refers to an inorganic, non-metallic fibrous product that is manufactured using a controlled mix of raw materials, usually silica or stone. The thermal and acoustic properties of this material, and its fire resistance, make it a great fit for multiple purposes.
Commercially, mineral wool insulation is made by melting recycled slag from steel mills and basalt stone and then spinning them into fiber that is used to make boards or batts.
Advantages of mineral wool
Mineral stone wool insulation batts have a better R-value rating as compared to the regular fiber insulation batts available over the counter at your local hardware store. Keep in mind, the higher the R-value of a material, the better it is as an insulator.
For example, mineral wool batts used to insulate 2×4 wall cavities have an R-value of 15. A fiberglass batt in the same wall cavity will have an R-value of only 11 or 13. However, you can specially order R-15 value fiberglass batts.
Stud cavities measuring 2×4 will have an R-value rating of around 13. Filling 2×6 wall cavities with mineral wool batts will give you an R-value of around 23, compared to the R-value of 19 that fiberglass batts will have.
Spray foam insulation has an R-value that is much higher than all of these, and for that reason, is also more expensive than fiberglass or mineral wool.
Mineral wool has better heat resistance properties as compared to other types of insulation. This means that in case of a fire in your home, mineral wool insulation batts retain their shape longer, preventing the spread of fire. In fact, your home can get additional fire protection using these batts with fire-rated sheathing to create a one-hour fire-rated assembly. So make sure you discuss these possibilities with your contractor before you begin the installation.
A large part of insulating your home involves protecting it against water damage. Mineral wool batts do not absorb water and stay intact even when they are wet. This means that in case your wall or roof begins to leak, these batts will retain their shape and remain undamaged as they dry out.
On the other hand, fiberglass or cellulose batts aren’t that resistant to water damage. They tend to compress, droop or clump up when they get wet. And if you have a serious leak, you may need to replace your insulation altogether.
Foam insulation, however, offers better water protection than even mineral wool insulation.
Mineral wool batts are denser than other stone insulation batts. This makes them a great choice for soundproofing interior walls, ceilings, and floors. Install these batts in between your room walls or in the joist spaces between floors to dampen sound.
Handling mineral wool
Certain precautions need to be taken while handling mineral wool insulation, just as you would with fiberglass. It is advisable to wear a full sleeve shirt, a dust mask, protective goggles, and gloves. The reason for this is that direct contact with mineral wool has been known to cause itching, and in some cases, even rashes.
While some contractors feel the effects are less than what you’d experience with fiberglass, others are sure the effects are worse. Either way, take the necessary precautions and avoid finding out!
Buying mineral wool insulation
In comparison to fiberglass insulation products, mineral wool insulation is a little more expensive. The average cost of mineral wool insulation per square foot ranges between $0.064 and $1.19. This means you are likely to spend between $145 and $200 to insulate a 500 square foot area.
These costs, of course, are if you are handling the installation yourself. Add around $300 for six hours of labor if you’re hiring professional help.
There are three big brands of thermal wall insulation that you could choose to buy wool insulation from: Johns Manville TempControl, Roxul ComfortBatt, and Thermafiber UltraBatt. Keep in mind though that you may need to custom order your batts depending on your requirements.
Installing mineral wool
It is a lot easier to install wool insulation than it is to install fiberglass insulation. Thanks to the high density and rigidity of mineral wool batts, they are a lot easier to measure and cut precisely. In fact, you can mark them by dragging the hook of your measuring tape across the surface.
Even when it comes to insulating your ceilings, mineral wool batts can just be pushed into place and they will stay. Fiberglass batts, on the other hand, are sure to fall out if you do not add extra support.