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Internet #205972559

Model #RXCB301525

R-30 ComfortBatt Fire Resistant Mineral Wool Insulation Batt 15 in. x 47 in. (12-bag)

  • Maintains R-Value year after year
  • Fire Resistant & Water Repellent
  • Ease of Installation - Cuts Easily & Friction Fits
  • See More Details

per month* suggested payments with months* financing on this $621 purchase*

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Product Overview

ROCKWOOL COMFORTBATT is a semi-rigid stone wool batt insulation for exterior wood and steel stud applications in both new construction and renovations. It features a unique flexible edge designed to compress as the batt is inserted then spring back, expanding the batt against the frame studs to give a complete fill. This flexibility ensures the expected R-value is achieved and maintained. Non-combustible and fire resistant, COMFORTBATT will not develop toxic smoke or promote flame spread, even when exposed directly to a fire. It is also offers water and moisture resistance and excellent sound absorbency. COMFORTBATT is an effective way to improve a home's energy efficiency. It is GREENGUARD Gold Certified and contributes to a healthier indoor environment.
  • Fire resistant due to its high melting temperature of 1177°C (2150°F)
  • Excellent sound absorbency
  • Water and moisture resistant; does not absorb moisture to maintain insulating value
  • Easily cut
  • Does not rot or promote growth of fungi or mildew
  • Flexible edge springs back, expanding the batt against the frame studs to provide a complete fill
  • 12 bags included on a pallet
  • Click here to learn more about Eco Options and Energy Efficiency
  • Buying guide and insulation calculator:

    insulation buying guide
    Insulation calculator button

Info & Guides

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Coverage Area (sq. ft.)
Product Length (ft.)
3.92 ft
Product Thickness (in.)
7.25 in
Product Width (in.)
47 in


Bag Size
4 ft. x 16 in. x 24 in.
Batt/Roll Size
3.92 ft. x 7.25 in. x 47 in.
Compatible Install Surface
Coverage Area per Bag (sq. ft.)
Faced or Unfaced
Insulation Features
Friction Fit
Insulation Location
Attic,Attic,Basement,Basement,Ceiling Insulation,Ceiling Insulation,Crawlspace,Crawlspace,Floor,Floor
Insulation R-Value
Insulation Type
Mineral Wool Insulation
Number of Bags
Pieces Per Bag
Pieces per Pallet
Product Weight (lb.)
Roll or Batt

Warranty / Certifications

Warranty Information

Questions & Answers

Typical questions asked about products:

  • Is the product durable?
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Customer Reviews

  • 4.8
    out of 479 reviews
  • 99% recommend this product
Filter by:
Showing 1-10 of 479 reviews
Great product! For 2 years I've been wanting to reinsulate the floor of my living room which sits...
Great product! For 2 years I've been wanting to reinsulate the floor of my living room which sits above my garage. Our winters here in NJ are very cold, and walking on a cold floor isn't very enjoyable. I didn't want to deal with the itchy fiberglass and also wanted something fire resistant for safety purposes, so I decided to go with the Rockwool mineral wool batts. My garage is 22x20 and framed 16 o.c. with 2x8 floor joists, so I ordered 15 bags of the R-30 ComfortBatt insulation to fill the spaces between the 2x8s. Shipping was fast and they didn't inform me my order was a week ahead of the shown delivery, but luckily I was home when they came. These are very dense and stay in place when placed overhead, but I would definitely recommend some type of eye protection and a mask when insulating overhead as little pieces tend to fall in your face.
by NeedMoreTools
3 people found this helpful
The best product!
I have replaced all of the old 1955 insulation in my home and i am working on the last room right now.I'm using R14 for 2 x 4 application inside my walls.I am so glad that i'm using Roxul as it has already shown to lower my heating bills and the accoustics changed right away.I don't hear much noise outside anymore.It is so easy to install and it's not itchy,i'm cutting the pieces with a bread knife.Thanks guys for a great product!
by Andreas
Delivery was great. Installation was easy. I had to cut the sheets in half to fit in between th...
Delivery was great. Installation was easy. I had to cut the sheets in half to fit in between the 24 inch joists. My husband installed the insulation. There was no insulation above the garage space, and now it's chock full. Easier to work with than fiberglass, but you still need a mask and gloves. Just a little itchy.
by lindu61
4 people found this helpful
This should make regular fiberglass insulation obsolete
I'm remodeling my 1950 mid century modern home one room at a time. I started with the hardest room to heat & cool, knocked out the old plaster & had the room sprayed with rigid & soft foam. The guys rushed the job & left some thin spots and even bare wood showing thru. I wanted to fill voids with Roxul but could not find it anywhere in Oklahoma so I hung the drywall anyway. Since then I've found a dealer 30 miles from me that can order it. I've since used Roxul in my sun room & garage. I like it better than the foam & I can easily install it myself.
by Dogwalker
Great product, easier and more sound dense, fire safe than regular fiberglass, inspector loved it...
Great product, easier and more sound dense, fire safe than regular fiberglass, inspector loved it, commented on the fire rating, make sure you get the knife to cut it with.
by DIYaddition
6 people found this helpful
Better Conformance to Joist Spacing
Fiberglass batts depend on springback to original shape, from large compression in packaging. That springiness then results in buckling if a bit oversize for the space. Rockwool doesn't do this. Lost contact with confining surfaces destroys insulation value.
by Attic Access
130 year old church restoration, ideal product
Installing comfort batt insulation in the walls and floor of a 130 year old William Critchlow Harris church/cottage upgrade. As this structure is a 'balloon' design, fire concern was paramount. Simple installation even with so many cuts, and huge long term benefits. Ideal application for your product.
by Michael
I am happy with this product.
I like it when i get asked what i'm putting into my walls.I let friends know that this product is safe to handle and not itchy.I'm using a bread knife to cut pieces to fit.I've got peace of mind knowing it's not going to grow mold,it's fire resistant,easy to install and i won't hear as much outside noise in my home.Right now i am installing this product and i am 3/4 completed.
by Andreas
We won't use anything but this product in our builds!
We do both custom and high volume manufacturing for tiny homes on wheels. It's important to us that the products we spec out to use are easy to install and work effectively for our applications. This product does exactly that. Sounds carry far and wide even in tiny homes. So, when we have new families moving into a small space, this product makes an excellent noise dampener in between closed off rooms to provide an element of privacy where it can normally be hard to find. Nevermind its obvious positives, this product is just far superior at the end of the day. It's our gold standard for each home that we send out of our shop and it makes us proud!
by Tina the Contractor
Ive been a fan of Roxul aka "Rockwool" ever since Mike Holmes Introduced it to his show Holmes on Homes. Had to wait a couple of years before it came to the States but when it did, i was elated!!! I got to try the water test and burning it, and boy was it amazing, just as described and show. I will never ever use the pink insulation ever again!! Re-insulating that garage picture i sent you in 90degree heat, after done that garage kept a temp of 70 degrees, i was extremely impressed!! ROXUL HEAD 4 LIFE!!!!!!!
by Coach
Showing 1-10 of 479 reviews