Non-combustible
Made from stone, rockwool doesn't burn and withstands very high temperatures — the reason it's used in fire-rated walls and around heat sources.
Rockwool — the stone-based form of mineral wool — is the premium pick when fire resistance, soundproofing, and moisture resistance matter. Dense, non-combustible, and higher R-value per inch than fiberglass.
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What It Is
Rockwool is a dense insulation spun from molten stone and slag into fibers — it's the rock-based form of what's also called mineral wool, so the two names refer to the same family of material. Because it's made from natural rock and recycled slag (a steel-production byproduct), it's also an eco-friendly, sustainable choice. What sets it apart from ordinary batts is what that stone origin gives it: it's non-combustible, it deadens sound and vibration better than lighter insulation, and it shrugs off water rather than soaking it up.
Those properties make it the premium choice for specific jobs — fire-rated assemblies, quiet interior walls, and moisture-prone spots — where a standard fiberglass batt or cellulose isn't the best fit. It costs more than those, so it's about using it where its strengths actually pay off, which is what we help you decide.
Why Rockwool
The properties that make rockwool worth the premium in the right spots — all inherent to the material.
Made from stone, rockwool doesn't burn and withstands very high temperatures — the reason it's used in fire-rated walls and around heat sources.
Its density makes it one of the best insulations for blocking noise — ideal for interior walls, media rooms, and shared walls.
Rockwool sheds water rather than absorbing it, and dries out without losing performance — a real advantage in damp-prone areas.
At roughly R-4 per inch, rockwool insulates a bit better per inch than standard fiberglass, so you get more from the same cavity depth.
Semi-rigid batts hold their shape and friction-fit tightly between studs and joists, so they don't sag or slump over time.
Because it's mineral-based and doesn't hold moisture, rockwool resists mold, and it offers no food value to pests.
Is It Right for You?
Rockwool is a premium material best used where its strengths matter. These are the situations it's made for.
Fire safety is a priority
Around a furnace, chimney, or between living units, rockwool's non-combustible fire resistance is exactly what you want.
You want quiet
For a media room, home office, bedroom wall, or a unit shared with neighbors, rockwool's sound dampening is a standout.
A moisture-prone space
In areas that see damp, rockwool's water resistance means it keeps performing where fiberglass would sag and lose R-value.
You want more R per inch
In a shallow cavity where you can't add depth, rockwool's higher R-value per inch squeezes more performance out of the space.
Interior sound walls
Insulating interior walls purely for quiet — not temperature — is a classic rockwool job thanks to its acoustic density.
Rim joists & exposed framing
Its rigidity and fire/moisture resistance make rockwool a strong pick for rim joists and other exposed, accessible framing.
How We Work
Rockwool performs when it's the right material for the job and fitted snugly. Here's how we handle every install.
We inspect the space and your goals — fire, sound, moisture, or R-value — and confirm whether rockwool is the right call or a lighter material would do.
We recommend the right rockwool batt or board and thickness to hit the fire, acoustic, or thermal target for your space.
If existing insulation is old, compressed, or contaminated, we remove and haul it away so the rockwool sits on a clean surface.
We cut the semi-rigid batts to size and friction-fit them snugly around studs, wiring, and obstructions — no gaps, no compression.
We confirm full, even coverage, clean up completely, and walk you through the finished job.

Why Attic Pros
For over 13 years, Bay Area homeowners and businesses have trusted us for insulation — because we recommend the right material for the job (not just the priciest), install it properly, and stand behind our work.
Real Customers, Real Results
Saed Abdullah was here today did a excellent service Thank you again for your help
I appreciate the great communication and flexibility. Samim arrived on time and an appointment went well.
I'm very impressed with AtticPros' expediency in scheduling a service call. Samim was courteous, well prepared and knowledgable. He quickly provided a thorough assessment of the situation. What really impressed me is how respectful of the (access through the bathroom) area he was. He cleaned up the attic access door and the (little) fallen insulation on the floor. I highly recommend attic pros for rodent extermination and clean up or any other service required.
Rodent intrusion and the associated damage they cause is the worst! After reading reviews, I decided on Attic Pros because they have great reviews and because they specialize in the work I needed. I was not disappointed. Within a few days of reaching out, Tom came out and did the estimate. The work began only two business days later! The work was scheduled over two days but they did it all in one! The guys arrived on time and were cheerful, polite, and pleasant to deal with. Kevin showed me pictures and video periodically throughout the day so I could see the work, start to finish. He answered all of my questions and explained everything clearly and patiently. Before they left they made sure there was no trash or debris left behind. The crawl space now looks like it belongs under a brand new home, it’s that clean and tidy. I highly recommend Attic Pros for all of your insulation and rodent elimination needs. Update: I came back and edited this, removing a star. The work and workers were great. However, a few days after the job, Julian from their business office messaged me that they had not received payment and the invoice was past due, even though they were paid IN FULL THE DAY OF WORK. Proof of payment was provided and he messaged me that a receipt would be sent when the payment was deposited. Very disappointing and unprofessional of him to go after a customer for payment when the problem lies with their accounts receivable. 10/14/26 I am adding to my review because issues had been discovered over time. They had missed a place where rats were entering, even though they had been out twice to check traps and found some. This guy did a less than thorough cleaning but he did close off the previously missed access point. My rat intrusion problem has been ongoing. 11/6/26 Attic Pros followed through and sent out Raul, an excellent worker, who took care of everything and made it right. While it may have been problematic for a bit, they kept working until it was all made right. They have been kind and communicative, specifically Paula. I will be calling them again in the Spring to work on a different area of my home.
Samim very professional
Did crawl space cleanup and rodent proofing. They were very efficient and thorough.
QUESTIONS, ANSWERED
Straight answers to the questions people actually ask about rockwool insulation — fire, sound, moisture, and how it compares. Still weighing your options? Our team is happy to help.
Talk to our team — we're here to help.
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Ready when you are
Tell us about your project — fire, sound, moisture, or thermal — and we'll assess the space, recommend whether rockwool is the right fit, and give you a clear, no-pressure estimate.
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