Rockwool Comfortboard 80 is a modular rigid stone wool insulation board made from rocks. If you’re going for a big-bad-wolf-proof building, Rockwool should be on your list to consider for insulating your exterior walls. Rockwool isn’t perfect for every application though, it can be expensive, heavy, and challenging to install.
Here, we cover the major benefits of Rockwool, its shortcomings, and what other options are available to insulate your walls in your home or commercial project.
Benefits of Rockwool Board
Rockwool has a number of things going for it. Here are some of the benefits of choosing Rockwool Comfortboard 80 to insulate your project:
Made from natural and recycled raw materials
Excellent fire resistance with no smoke production or flame spread
Termite and insect resistant
High compressive strength
Provides acoustic sound absorption
Where to Use Rockwool Comfortboard 80
Rockwool Comfortboard 80 is designed for use on the exterior side of the wall for continuous insulation. It’s installed with 3-inch washers and nails, and is attached to sheathing over a vapor barrier or house wrap. Other applications can include foundation walls and under concrete slabs.
Disadvantages of Rockwool Insulation
Rockwool is a great option for some projects, however this type of insulation isn’t always the best for every application. Some of the shortcomings of Rockwool Comfortboard include:
Weight
It’s heavy, at over 50 lbs. per 4’ x 8’ board at 2” thickness, which makes installation laborious.
R-Value
At R4.2 per inch, Rockwool Comfortboard 80 is a middle-of-the-road option when it comes to thermal R-value performance.
Cost and Availability
Rockwool Comfortboard 80 can be difficult for homeowners to obtain because it is not typically stocked in big box stores, so it can be a challenge to obtain, and pricier to purchase.
An Alternative to Rockwool
Luckily, there is an alternative to Rockwool Comfortboard 80. Polyiso is a comparable option to Rockwool when it comes to installing insulation on walls. Taking it a step further, polyiso outperforms Rockwool when it comes to installability, thermal performance, and price point. If you’re looking for a less expensive, lightweight alternative to Rockwool—without sacrificing on performance, consider polyiso.
Easier Installation
Polyiso can be installed in the same locations and applications as Rockwool as a continuous insulation, but with significantly less weight bearing on your installers and your walls. Since polyiso is made out of foam, it’s inherently lightweight and can be carried and maneuvered easily by a single installer without suffering from the fatigue of lifting heavy Rockwool boards, which may require two installers per board, or smaller board sizes.
R-Value Thermal Performance
It’s hard to beat the thermal performance of polyiso. At R6 per inch, it’s one of the best thermal insulation options for walls. With polyiso products like Rmax Durasheath® building envelope insulation, you can achieve an R21.8 with just 3-½” thickness, whereas achieving this same R-value with Rockwool Comfortboard 80 requires over 5” thickness.
Affordability
Polyiso insulation is affordably priced at just over a dollar per square foot for a two inch thickness. Rockwool, on the other hand, can be quite pricey at nearly two dollars per square foot at the same thickness. Since you’re getting less thermal insulating power for the same thickness, that’s a double whammy.
Availability
Polyiso is more readily available for purchase by ordinary homeowners, because it is available at building supply stores. Rockwool Comfortboard 80, on the other hand, can be a specialty item that is not stocked in stores and often requires a special order and larger quantities.
Tailored Performance
Polyiso has a unique advantage over most other wall insulation types, including Rockwool Comfortboard 80—it can be tailored to meet your project’s needs by applying an appropriate facer. Because polyiso not only accepts, but requires a facer during production, it gives you the choice between different performance properties that you want to incorporate.
For example, if you’re looking for an air and vapor barrier, you can find an all-in-one solution with Rmax’s ECOMAXci® FR Air Barrier. Rockwool, on the other hand, is vapor permeable and requires a second product to add vapor protection.
Here are more polyiso insulation products that are available as an alternative to Rockwool Comfortbatt 80:
ECOMAXci® FR Ply: Fire-Resistant Plywood Faced Polyiso for Cladding Attachment
R-Matte® Plus-3: Aluminum faced polyiso available at your local big box retailer
Thermasheath®: Reinforced aluminum faced polyiso boards
Thermasheath®-SI: Structural composite insulation with aluminum facers
Find the Perfect Insulation for Your Next Project with Rmax
Rmax has been in the insulation business for decades and has honed and perfected its evolving product line to meet building codes and customer needs. We have a full lineup of insulation solutions to help you meet your project’s requirements and get your next job started off on the right foot.
Talk with one of our experts today today to get help choosing the right insulation for your project!