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
Attic Pros recently replaced my old insulation with new insulation. I called them back today 3 weeks later to check on the Rat traps they placed in the Attic as I experienced an unusual odor coming from the air vents throughout the house. Jose of Attic Pros responded and was a very upbeat chearful person who explained what he was going to do prior to going into the Attic to check on the Rat Traps. Fortunately the traps were still set with no activity. Jose took photos ( see attached) while he was in the Attic which showed no activity. I later found that the odor was a filter in the hvac systrem which had debris which causec the odor. Jose completed the inspection by walking around the house and inspecting the outside vents which I appreciated. All the Attic Pro employees which I have come into contact with are Professional, friend;y an do a thouough job completing whatever jobs in their field are requested.
These guys are great! Wais Amiry came out to take a look at my attic for rat infestation, they showed up fast and they were super professional. Would use them again!
Denis from Attic Pros was very thorough and does a great job. He is thoughtful, patient and a good listener to all my concerns. Our home is peaceful now that we don’t have any rodents! I recommend him highly.
Tom is a professional and did a very detailed inspection, also gave additional details to prevent in future infestation.
My wife and I found mice droppings in our kitchen cabinet. We reached out to Attic Pros and was connected with Tom. He was very professional and thorough with his inspection. We went through our crawl space and attic. Gave us a full rundown of issues/problems we may be experiencing now and potentially in the future. Thanks for your expertise and quick follow up with the quote and service Tom.
These guys are awesome. Super clear comms to schedule, then received an extremely thorough consultation. We eventually decided to go with them as other shops in the area didn't communicate as well as Attic Pros.
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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