Mineral wool insulation is made from natural stone and recycled slag. It offers strong fire resistance, helps reduce energy costs, improves indoor comfort, and blocks out noise. Its ability to resist moisture also helps prevent mold growth. This flexible material works well in walls, roofs, attics, and floors, making it a solid choice for both homes and commercial buildings.

At Star Spray Foam, we provide insulation solutions that match the needs of different environments—from humid climates to areas with extreme heat or cold. Mineral wool is durable, reliable, and built to perform under tough conditions.

Have questions or need help deciding if mineral wool is right for your space? Contact us today to schedule a free estimate or speak with one of our insulation specialists.

What Is Mineral Wool Insulation?

Mineral wool insulation is a cost-effective and widely used solution that improves the energy efficiency and comfort of homes and commercial properties. It’s well-known for its fire resistance and sound-dampening qualities, making it useful in hot climates, cold regions, damp environments, or any space where noise control matters.

1. Defining Mineral Wool Insulation

Mineral wool, also called man-made mineral fiber (SMF), is a type of inorganic, fire-resistant insulation created by melting natural rock like basalt and industrial by-products such as steel slag. Once heated, these materials are spun into fine fibers that trap air, providing solid thermal and sound insulation.

Compared to fiberglass, mineral wool is denser. This added density increases its fire resistance and soundproofing performance without sacrificing thermal efficiency. Its long-lasting structure makes it a perfect fit for demanding environments.

2. What It’s Made Of

The main ingredients in mineral wool insulation are sustainable materials—primarily basalt rock, iron-ore waste, and recycled steel slag. These components are melted and spun into thick fibers at temperatures exceeding 2,700°F.

This fiber-rich texture contributes to strong thermal insulation and creates a more comfortable indoor climate. While many mineral wool products include recycled content, the energy-intensive production process does reduce some of the environmental benefits. Still, its long life and performance often outweigh that concern.

With a vapor permeability rating around 50 perms, mineral wool is effective at managing moisture. It continues to insulate well over time, even in damp conditions. Contractors appreciate mineral wool for its ability to control sound, resist moisture, and improve indoor energy performance.

3. How Mineral Wool Insulation Works

Mineral wool works by trapping air in its dense network of fibers. This method slows the movement of heat, helping buildings stay cooler in summer and warmer in winter. Its structure also absorbs sound waves, which cuts down on noise transfer between rooms or from outdoors.

What makes mineral wool stand out is how well it holds its R-value over time. It retains more than 90% of its insulation rating, even after long exposure to moisture. Its resistance to high heat and overall durability make it a strong choice for both thermal and acoustic applications.

Key Benefits of Mineral Wool Insulation

Mineral wool insulation is one of the most flexible and effective insulation materials for both homes and commercial spaces. It supports energy savings, noise reduction, fire safety, moisture control, and environmental responsibility.

Here’s a closer look:

1. Improves Energy Efficiency

Compared to fiberglass, mineral wool has higher R-values and lower thermal conductivity, typically between 0.017 and 0.023 BTU/hr·ft·°F. This means better temperature regulation and less strain on your HVAC system.

Homes with mineral wool insulation stay more comfortable year-round while using less energy. With a minimum lifespan of 55 years, this type of insulation offers long-term performance. It’s available in a range of thicknesses—from ½ inch to 6 inches—allowing for maximum thermal resistance depending on your needs.

2. Reduces Noise

Thanks to its dense structure, mineral wool is an excellent sound barrier. It can block over 50 decibels, making rooms quieter and more peaceful. This capability makes it ideal for home offices, theaters, recording studios, or any space where controlling sound is important.

3. High Fire Resistance

Mineral wool can withstand temperatures over 2,150°F (ca. 1,177 °C). It holds a Euro Class A fire rating, which is the highest possible for insulation products. It acts as a barrier to slow flame spread and gives people more time to evacuate during emergencies.

Unlike some other materials, mineral wool doesn’t give off harmful fumes or contribute to fire growth. It also doesn’t conduct heat, making it safer for high-performance buildings.

4. Manages Moisture and Resists Mold

Because it’s made from inorganic materials, mineral wool naturally repels moisture and doesn’t support fungal growth. Its vapor-permeable structure allows water vapor to escape rather than build up inside walls or ceilings.

This makes it a smart choice for areas prone to humidity, like New Orleans. It keeps indoor environments safer and helps avoid long-term structural damage caused by trapped moisture.

5. Encourages More Sustainable Construction

Mineral wool insulation often includes up to 80% recycled materials. Using this insulation can help lower carbon emissions and reduce waste.

In Europe, mineral wool has helped buildings cut energy use by up to 80%. Choosing this material can contribute to a cleaner environment while still offering top insulation performance at home.

Installation and Usage

Proper installation helps mineral wool perform at its best. Knowing how to handle the material and apply it correctly supports energy savings and keeps indoor air clean and dry.

1. Getting Started

You’ll need basic tools: a utility knife, tape measure, straightedge, gloves, goggles, and a dust mask. Before cutting anything, measure your wall cavities or ceiling spaces accurately. This approach prevents gaps that could reduce the insulation’s effectiveness.

Check with local code enforcement to make sure your project meets current safety and energy standards.

2. Installing the Material

Cut each piece to fit snugly between the studs. Use firm pressure to place the insulation, but don’t compress it too much—that reduces how well it insulates.

Make sure seams are tight and gap-free to block airflow. Wear gloves and masks to avoid irritation from the fibers.

3. Dealing with Challenges

If you’re working around uneven framing or curved edges, cut smaller pieces to fill gaps. Always keep the workspace ventilated and clean up fiber dust right away.

4. Keeping It Efficient Over Time

Use caulk or foam to seal small openings after installing the insulation. Stick with reliable brands to avoid quality issues.

Inspect insulation periodically. Watch for any settling, shifting, or damage that could affect performance.

Choosing the Right Insulation

The right insulation depends on your building’s shape, the climate in your area, and where the insulation will go. Attics need high R-value material to reduce heat loss. Mineral wool works well in walls by balancing thermal performance and soundproofing.

In older homes, rigid foam boards at rim joists can make a big difference without needing a full remodel. Moisture levels and regional weather patterns also influence which insulation makes the most sense.

Considering the Environment

Insulation made from recycled steel slag, like mineral wool, helps support eco-friendly construction. When reviewing your options, look at the entire lifecycle of each material. EPS foam, for instance, emits more emissions but offers good insulation. Mineral wool offers a safer, cleaner alternative for both health and environmental impact.

Safety and Indoor Air Quality

Mineral wool doesn’t attract mold, pests, or allergens. When installed well, it improves overall air quality in your home. Products that include vapor barriers can also help control moisture, keeping things dry and durable.

Improve Comfort with Mineral Wool Insulation

Mineral wool is a smart choice for homeowners who want reliable insulation, especially in humid areas like New Orleans. It’s energy-efficient, water-resistant, and holds strong under heat. When installed in walls, attics, or floors, it helps reduce your energy bills and keeps your home quiet and safe.

If you’re ready to upgrade your insulation, reach out to us at Star Spray Foam for professional guidance and a free estimate. We’ll help you get the results you’re looking for—comfort, savings, and peace of mind. Call us today!