Mineral wool and fiberglass insulation are two widely used types of insulation in residential construction, with Owens Corning and Rockwool being the most popular brands. While both are referred to as mineral wool insulation, they are made from different minerals – one from stone or rocks and the other from glass.
Rockwool Insulation
Let’s start with stone wool, which primarily consists of basalt rock, slag, coke, and recycled stone wool waste. The manufacturing process involves melting basalt rock, slag, and briquettes with coke at extremely high temperatures, resulting in molten lava. The liquid is then spun into fiber-like strands and bonded together using a phenol-urea-formaldehyde resin.
The tufts of stone wool are carried on a conveyor belt to a pendulum device. The pendulum moves back and forth, spraying the stone wool in layers on another conveyor belt. Rollers compress the layers to make them more dense. They are taken to a long oven and heated to cure the resin binders. Blades and water jets cut the stone wool into batts. Stone wool, offered by manufacturers like Roxul or Rockwool, is known for its high density, dimensional stability, and excellent sound absorption properties.
Fiberglass Insulation
On the other hand, fiberglass insulation is made from sand or silicon dioxide, soda ash or sodium carbonate, limestone or calcium bicarbonate, and crushed recycled glass called cullet. After heating all the ingredients to a high temperature, molten glass is formed, which is then rapidly cooled to create short strands of glass fibers. These fibers are treated with a pink polymer glue to give them their recognizable color. A conveyor belt takes the fibers to a 500F oven which sets the glue. Circular saws cut the large sheets and an inkjet prints the manufacturer’s details and the R value.In the last stage, the fibers are compacted and pushed into bags. Owens Corning is a prominent manufacturer of fiberglass insulation, offering a variety of products like EcoTouch Insulation.
Differences
The manufacturing principles of these two types of insulation are very similar even though their ingredients are different. Let’s look at some other differences between the two.
- Cost: Stone wool insulation is generally almost twice the price of fiberglass insulation.
- Weight: Stone wool is three times denser than fiberglass, making it heavier.
- Thermal Drift: Both insulation types operate on trapped air between the fibers, but thermal drift may occur over time when the batts are compressed.
- Dimensional Stability: Stone wool maintains its shape and has lower thermal drift compared to the fluffy fiberglass.
- Sound Absorption: The high density of stone wool leads to better sound absorption properties compared to fiberglass.
- Waterproof: Stone wool is naturally hydrophobic, while fiberglass can absorb water and lose its insulating properties.
- Mold Resistance: Stone wool resists rot, fungi, mold, and bacterial growth, unlike fiberglass.
- Fire Resistance: Stone wool is naturally fire-resistant, while fiberglass is less fire-resistant and will burn.
- Ease of Use: Stone wool is easier to cut and install than fiberglass.
- Health Risks: Both materials require safety precautions during handling to avoid skin contact and inhalation of fibers.
- Recycling: Some brands of mineral wool may use recycled content, while fiberglass typically has around 30% recycled content.
- Vapor Permeability: Both materials are vapor permeable, but proper orientation is crucial for paper or foil-faced fiberglass batts.
In conclusion, stone wool insulation appears to have distinct advantages over fiberglass, offering superior qualities in areas like density, water repellency, mold resistance, and fire resistance. However, both materials have their applications and should be chosen based on specific project requirements and preferences.
At the end of the day, the choice between mineral wool and fiberglass insulation depends on individual needs, budget constraints, and environmental considerations. When making this decision, it is essential to weigh the benefits and drawbacks of each type to find the most suitable solution for your construction project.
SOURCES:
https://www.youtube.com/watch?v=F_icE5rMEBo
https://www.youtube.com/watch?v=zkBD0DLfXNs
https://www.youtube.com/watch?v=t6FWPTZjwLo
https://www.youtube.com/watch?v=mnNheTAe1ZU
