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Frequently Asked Questions

Frequently Asked Questions

General questions

1) What is stone wool?

ROXUL insulation is a rock-based mineral fiber insulation comprised of Basalt rock and Recycled Slag. Basalt is a volcanic rock(abundant in the earth), and slag is a by-product of the steel and copper industry. The minerals are melted and spun into fibers.

2) What happens if ROXUL insulation gets wet?

ROXUL insulation is moisture resistant yet vapor permeable. In the event the insulation becomes damp or wet, the insulation, when thoroughly dried, will maintain the original performance characteristics.

ROXUL stone wool insulation does not wick water, which means that any bulk water that contacts the outer surface will drain and not be absorbed into the body of the insulation.

3) Are ROXUL products mold resistant?

ROXUL products are inorganic which provide no food source for mold to grow. ROXUL products are tested to ASTM C1338 – A Standard Test for Determining Fungi Resistance – and passes with zero fungal growth.

4) Are ROXUL products rodent resistant?

There is no test method to determine whether or not any product is rodent resistant. ROXUL’s reputation as a rodent-resistant insulation is mainly based on word of mouth and lack of negative feedback from numerous customers who use our products in “cottage country”. That being said, if a certain pest type is a nuisance to your particular area, best practice is to protect the insulation. 

5) Does ROXUL make blowing wool insulation?

ROXUL insulation is only manufactured in batt, board, and pipe forms.

6) ROXUL WARRANTY – What is ROXUL’s warranty information?

ROXUL Inc. Terms and Conditions regarding Limited Warranty

Here at ROXUL Inc., we are committed to ensuring the highest standard of quality possible in everything we do. We are proud of our constant, consistent efforts to improve our operations to ensure we exceed your expectations on every product that leaves any of our facilities.  As ROXUL Inc. has no control over installation design and workmanship, accessory materials or application conditions, ROXUL Inc. does not warrant the performance or results of any installation containing ROXUL Inc. products. ROXUL Inc.’s overall liability and the remedies available are limited by the general terms and conditions of sale.


The limited warranty in the terms and conditions is in lieu of all other warranties and conditions expressed or implied, including the warranties of merchantability and fitness for a particular purpose.

7) RECYCLED CONTENT – How much Recycled Content is in ROXUL Products?

ROXUL insulation is a stone-based mineral fiber insulation comprised of Basalt rock and Recycled Slag.

The recycled content in mineral wool is derived from the steel slag.

ROXUL products contain between 16% or 40% pre-consumer recycled material dependent on the ROXUL manufacturing facility location.


The amount of recycled content is optimized to provide the ideal thermal, acoustic, and fire protection properties from ROXUL products, while still maximizing the recycled content.

8) How does ROXUL help to earn LEED Certification?

ROXUL products can be used as a contribution to obtaining LEED certification in residential and commercial buildings. ROXUL has made available a LEED calculator that can help to provide LEED documentation to meet required standards. Please see here to be directed to the ROXUL LEED calculator.

9) Does ROXUL Supply Complete Systems?

ROXUL manufactures and distributes insulation products only; but we do provide system design advice on fire, acoustics, thermal, and moisture performance of assemblies.  

10) Does ROXUL contain formaldehyde?

Standard ROXUL products do currently use a phenol formaldehyde binder during production. During manufacturing, the binder is cured at very high temperatures leaving only trace amounts in the product after it is produced. ROXUL AFB®, SAFE’n’SOUND®, and COMFORTBATT® have all achieved GREENGUARD GOLD status for indoor air quality.


ROXUL also offers a no added formaldehyde product, AFB evo™, starting July 1st 2017. This product is produced with a new formaldehyde free binder, and retains all of the properties of the original AFB® product. Please contact your local specifications manager for more information.

11) Does ROXUL slag contain heavy metals?

ROXUL products do not contain any heavy metals. Please contact ROXUL Technical Support to receive specific information on materials found in ROXUL products.

12) Why are ROXUL batts priced at a premium?

ROXUL Batts are an average of 3x denser than fiberglass batts; providing a better fit in the cavity and delivering superior thermal, sound and fire control.  

13) What is the best way to cut ROXUL batts and boards?

A serrated knife is always the best way to cut stone wool; we advise not to use utility knives as they will dull too quickly and end up tearing the batts, a bread knife works extremely well with our products.

14) Does ROXUL have insulation for Metal Building applications?

ROXUL has a variety of insulation products for Metal Buildings for roof and wall applications. In addition ROXUL has available both 1HR and 2HR fire rated assemblies for metal buildings in close lot line applications. Please contact your local ROXUL representative for specific applications. Please see more information on our metal building products here.

15) Does ROXUL sell directly to Builders/Contractors/Installers?

ROXUL products are available through our broad network of commercial insulation distributors. Please contact your local ROXUL sales rep for information on local distributors.

16) Can I tape the seams of the CAVITYROCK® product?

CAVITYROCK® insulation will not act as a vapor and/or an air barrier and therefore no need to tape the seams of the boards. Ensure when installing the insulation that the boards are butted closely together so that there is no space between each successive board. 

17) Can ROXUL help designers meet the thermal needs of their wall assemblies?

Yes, ROXUL has a comprehensive Technical Department and Building Science Team that can assist you with the design to help you meet your needs. Please contact your local representative for details, or visit the Building Science contact page.Can ROXUL help designers meet the thermal needs of their wall assemblies?

18) Can ROXUL be used with direct applied stucco?

ROXUL recommends applying a ventilated stucco system using ROXUL COMFORTBAORD™ 80 attached with furring strips. Please ensure the wall assembly is designed to hold the required weight of the system when applying a heavy weight cladding. A stucco wall assembly using COMFORTBOARD™ can be found in the Residential Insulated Sheathing – Installation guide

19) What are UL/ULC approvals?

UL approvals, or UL Listing, signify that a product has been tested and has met nationally recognized requirements in standards for safety. These tests are run by a private, third party company and approvals are listed on ROXUL technical data sheets. ULC Listings are used for Canadian tested assemblies. 

20) Where can we find designs for UL?

ROXUL offers a list of UL designs on the ROXUL website, which can be found by searching UL Listing. This will include curtain wall, fire wall, and fire stopping designs. Other UL rated assemblies can be found on the UL database, linked to here. This database contains UL listings for wall, floor/ceiling as well as roofing assemblies.

21) Does ROXUL come in different colours?

ROXUL insulation comes in one standard natural colour. Some options are available for facing of ROXUL products in foil or black colours. Please contact your local sales representative for facing details.

22) How long will ROXUL last before it has to be replaced?

ROXUL insulation should last the lifetime of your building if installed in a properly designed system according to spec. ROXUL products will not decay since they are inorganic, so they will retain their properties assuming no physical damage occurs.

23) Is there any off-gassing with ROXUL products?

Off-gassing refers to the gasses emitted from insulation that has had gas blown into it during production. ROXUL insulation does not use this process during manufacturing, and therefore ROXUL products do not off-gas.

24) Can ROXUL be used in an oven/stove application?

ROXUL products have a high melting point of 2150°F and can operate at high temperatures. We do not currently have tested assemblies for these applications. The recommended commercial or industrial ROXUL product will depend on the temperature and usage of the stove/oven. Please contact your local representative to find specific products.

25) Does AFB® come sized for wood studs?

No, AFB® is only available in steel stud sizes. If you would like to insulate wood studs we would recommend using our residential product, ROXUL SAFE’n’SOUND®.

26) What is the thickest I can get the ROXUL product?

Depending on the application ROXUL can make a board product up to 6” thick and a batt product 7.25” thick.  ROXUL products can also be layered to achieve a higher R-value when needed. For example: R15 + R30 = R45.

27) What are the dimensions of the product?

ROXUL products are produced to accommodate standard construction practices. Common Sizes are 24 x 48 and 16 x 48 at a variety of thickness depending on product. Larger and custom sizes can be produced however minimum order quantities are usually required.

28) Does ROXUL make custom sized products?

ROXUL can produce custom products depending on order quantity and line capabilities, please contact your local representative for details.

29) Can facings be applied to ROXUL stone wool products?

Facings can be applied to some of our board products during the production process, and we also have a network of fabricators that can apply facers to our product. Please contact your local sales rep for information on facing options.

30) Is Black Scrim available on ROXUL CAVITYROCK®?

ROXUL does not produce CAVITYROCK® with a black scrim facing. If a black facing is required for aesthetics a separately installed vapor permeable, water resistant black membrane is recommended.

31) Where can I purchase ROCKBOARD® PG?

ROCKBOARD® PG is no longer available to purchase from ROXUL. We do still supply third party fabricators that continue to produce this product for purchase. Please contact your local sales representative who can help direct you to a local fabricator.

32) What is the R-value on each ROXUL product?

Please visit the ROXUL product page and/or specific product technical data sheet for the R-value of ROXUL products. 

33) What are the R-values of AFB® and SAFE’n’SOUND®?

Interior insulation products do not require an R-value and as such, we do not brand our interior insulation with this information. 

Product Differences

1) What is the difference between ROXUL batt products?

ROXUL batt products are made to fit inside wall or ceiling cavities and are friction fit into place. All of these products will contain thermal, acoustic, and fire protection properties, but each one is designed and optimized for its specific application.

SAFE’n’SOUND® is a product used in residential interior applications. It is available in a 3” thickness and is ideal for either wood or steel stud interior partition walls in residential houses. This product is designed for sound attenuation and fire protection.

AFB® is designed for interior walls in commercial buildings. This product is only available in steel stud sizing varying in thickness from 1” to 6” and can be used for a variety of interior partitions in any commercial setting.

ROXUL COMFORTBATT® is designed for exterior cavities between wood or steel studs. It is labeled with an R-value and is tested and optimised for its thermal properties.


ROXUL SAFE™ is a fire stopping product that when used with a fire sealant can block the passage of fire and smoke. It is used primarily to fill perimeter gaps in between floor slabs and exterior walls, as well as around pipe openings and ducts through walls.

2) What is the difference between ROXUL board products?

ROXUL board insulation products are designed to meet a multitude of different design applications.

ROCKBOARD® is available in three different densities. ROCKBOARD® 40, 4lbs/ft3, ROCKBOARD® 60, 6lbs/ft3, and ROCKBOARD® 80, 8lbs/ft3. With three different densities to offer ROCKBOARD® is ideal for a multipurpose insulation board used for applications such as mechanical rooms and sound absorption panels.


CAVITYROCK® is an exterior insulation used underneath the cladding of a building. This product is available in a single density for a low thickness product as well as a dual density which provides more durability against loads and cladding attachments. This product would be used with cladding attachments such as structurally supported cladding (clips/girts/rails) or self-supported cladding (brick on shelf angle or ledge). Different cladding and fastening methods can be found in the Cladding Attachment Solutions guide.


COMFORTBOARD™ is a rigid insulation and can also be used as an exterior insulation when using insulation supported cladding, such as wood strapping or hat track screwed through the insulation. COMFORTBOARD™ can also be used for below slab applications and foundation wall insulation.

COMFORTBOARD™ is available in two different densities; COMFORTBOARD™ 80, at 8 lbs/ft3 density, or COMFORTBOARD™ 110, at 11 lbs/ft3 density. The increase in density will provide more compressive strength and increased durability during installation, while both products provide the same base thermal and acoustic properties.



ROXUL CURTAINROCK® is used for curtain wall application and is available in three different densities; 3.5lbs/ft3, 4.0lbs/ft3, and 8.0lbs/ft3. This allows for a variety of curtainwall applications and attachment methods. CURTAINROCK® 40 and 80 are UL listed to be used in perimeter fire containment systems.


1) What is the difference between ROXUL SAFE’n’SOUND® and COMFORTBATT®?

ROXUL SAFE’n’SOUND® is designed specifically for sound attenuation. The density and thickness of the product is optimised for acoustical performance. SAFE’n’SOUND® is not branded with an R value as it’s typically used in interior partition walls that do not require an R value. Therefore, SAFE’n’SOUND® would not pass an inspection if used in an exterior wall.

ROXUL COMFORTBATT® is used in exterior walls and so the quality control performed on the product is done to meet the standards required per R value labelling. It is also branded with an R value and so would pass a home inspection so long as the R value as per the building code is met. Like all our products, ROXUL COMFORTBATT® is made out of mineral wool and therefore offers some acoustical performance.

2) What fastener would I use with ROXUL COMFORTBOARD®?

The fastener type used should be appropriate to the substrate [concrete wall, wood stud, etc.] Please refer to the fastener guideline document found on our website. 

3) Can glue or an adhesive be used to attach ROXUL COMFORTBOARD®?

You can use a construction grade glue/adhesive to temporarily attach the insulation in a situation where the stud wall is being built on top/after the insulation. In this case, the stud wall would hold the insulation in place. We do not recommend permanently attaching the insulation using glue as this may cause the insulation to peel/fall off once the glue dries.

4) May I still use ROXUL SAFE’n’SOUND® in an exterior wall?

Yes, you can but if inspected, would not pass the inspection as a product with a labelled R value is required.

5) Attachment details

For information on fastening techniques for ROXUL products please refer to our Fastener Guidelines. This will give an overview of different fasteners that can be used with ROXUL board products.

6) How long can ROXUL rigid products be exposed on the exterior wall before the cladding has to be put on?

ROXUL advises to install the cladding as soon as possible after the insulation has been installed, however, if the insulation is exposed and becomes wet, ROXUL recommends that the insulation dries out completely then the cladding can be installed without our insulation experiencing any performance loss provided there is no physical damage or contamination to the product. Damaged product should be replaced prior to cladding installation.

7) Can ROXUL be used outside and below the foundation walls?

Yes, our rigid boards, COMFORTBOARD™ 80 and COMFORTBOARD™ 110 can be used inside and outside of the foundation wall, as well as for under slab insulation applications. Because of its high density, vapor permeability, and inorganic nature this product is ideal for applications below poured concrete slabs and between the slab edge and foundation wall.

8) How do you reduce thermal bridging?

Thermal bridging is the heat transfer through materials such as wood or steel studs that do not have the same thermal properties as insulation, providing a path for heat to travel through the wall more easily. This effect can be reduced by adding a layer of continuous insulation around the exterior of the building that does not include a stud wall. This will provide an extra layer of insulation while reducing the heat that can travel through the studs. The recommended products for a continuous insulation are COMFORTBOARD™ or ROXUL CAVITYROCK®.

9) Can I use AFB® on exterior walls?

AFB® is designed for interior partition walls in steel stud commercial applications. It is ideal for sound attenuation and fire protection. The recommended product for external framing is COMFORTBATT®.

10) Can I use ROXUL PLUS® MB on an exterior rain-screen?

PLUS® MB is not recommended as a rain-screen product. This product does not have the needed rigidity and durability for this application. The recommended product for this application is either CAVITYROCK® or COMFORTBOARD™.

11) Can you use two layers of insulation on the exterior of a wall to meet your insulation goals?

Yes, you can use two layers of insulation on the exterior of a building with no issues with thermal performance, please see ROXUL design guides or contact your local representative for more details.  


1) Can I walk on ROXUL roof products?

ROXUL TOPROCK® DD and TOPROCK® DD Plus roof boards are meant to be installed on the roof and can be walked on during the normal course of construction or the use of the building. ROXUL MONOBOARD® Plus and MONOBOARD® are meant to be installed as coverboard products over other insulation products.  The National Roofing Contractor’s Association (NRCA) recommends that areas that experience heavy foot traffic be installed with an additional protection cover board layer to protect any thermal insulation products. It is recommended that staging areas be protected during the construction process.

2) Can I torch to TOPROCK® DD or MONOBOARD®? What does the “Plus” mean?

ROXUL TOPROCK® DD Plus and MONOBOARD® Plus products are impregnated with a bitumen coating that allows for adhesion between the boards and the membrane when installed in a torch- or hot mop applied roof. 

3) Do I need a protection board over TOPROCK® DD?

You are not required to install a protection board over TOPROCK® DD or TOPROCK® DD Plus products as the products are approved as coverboard products. Some designs may call for an additional protection or cover board layer for various reasons. 

4) Can I install multiple layers of TOPROCK® DD?

Yes, multiple layers of TOPROCK® DD can be used to meet building code or design requirements. For mechanically fastened systems, TOPROCK® DD can be used as the top layer. For hot applied and some cold applied systems, TOPROCK® DD Plus can be used as the top layer. 

5) Can I use TOPROCK® DD in the vertical applications such as parapets and curb details?

If desired, TOPROCK® DD Plus can be installed in vertical applications. ROXUL also manufactures Cant strips to allow for an easier transition to parapet. 

6) Can I use TOPROCK® DD under sloped metal roofing?

TOPROCK® DD is approved in some metal roofing applications, contact ROXUL Technical Solutions or your preferred metal panel manufacturer to determine if it is approved in their system. 

7) What is the difference between MONOBOARD® products and TOPROCK® DD products?

MONOBOARD® products are mono-density products designed to be roof cover boards or protection boards and are only available in 1” thicknesses. TOPROCK® DD products are dual-density products with an integrated roof cover board that can be used as either thermal insulation or as a thermal cover board over other insulation.  TOPROCK® DD boards also come in thicknesses ranging from 2” to 6” to meet building code requirements. 

8) Can you fully adhere a single ply membrane to ROXUL roof boards?

ROXUL roof boards have been approved with a limited number of single-ply roof membranes. Consult Roofnav listings or contact ROXUL Technical Solutions for more information on approved systems. 

9) Does ROXUL® manufacture tapered panels? Does ROXUL manufacture flute filler products?

ROXUL is able to provide tapered stone wool panels in a variety of thicknesses, we work with our partners to provide the system you require for positive drainage on your roof to reduce ponding. ROXUL tapered panels are available in tapered to zero panels and can help reduce jobsite fabrication. In addition to tapered panels, ROXUL is able to provide additional fabricated accessories such as flute fillers and cant strips. Click here to learn more or contact your local ROXUL sales representative.

10) Can I use TOPROCK® DD and TOPROCK® DD Plus in wall and floor systems?

No, ROXUL roof boards are designed specifically for low-slope roof applications. For more information on products available for floors/ceilings click here. For more information on products available for walls click here.

Floors & Ceilings


1) How would I insulate my attic?

We recommend the use of ROXUL COMFORTBATT® to insulate an attic. The insulation used would depend on the constraints of the application [space/required R value as per building code, etc]. Be sure to use a vapour control layer when required. Please see our YouTube channel for how-to videos as well as the DIY Energy Star guide for more information.  

2) How would I insulate my crawl space?

You can insulate your crawl space using ROXUL COMFORTBOARD® or COMFORTBATT®. The specific type of insulation used would depend on the constraints of the application [space/required R value as per building code, etc]. Be sure to use a vapour control layer when required.  Please see our YouTube channel for how-to videos as well as the DIY Energy Star guide for more information.  

3) Do you offer a loose-fill product for attics?

We used to offer a product called RockFill®, however it was a business decision to discontinue this product.  Due to the nature of our product there were also issues with the blowing equipment and so we discontinued RockFill®. 

Fire Protection

1) What is the fire rating of ROXUL insulation by itself?

ROXUL insulation products do not carry a fire rating in minutes or hours by themselves. Fire ratings are based off of complete wall or floor/ceiling assemblies, as every part of the assembly will affect the final rating. 

2) What is a fire stop vs a fire blocking material?

A fire blocking material is a material installed within concealed spaces that resist or slow the migration of fire for a period of time. This includes anything from the insulation inside a wall to a fire rated gypsum board.

Fire stopping refers to materials protecting and stopping fire spread around penetrations of an assembly, such as pipes or wires. ROXUL offers fire stopping products such as ROXUL SAFE™ to be used as part of the fire protection system. ROXUL SAFE™ will typically be applied with a fire sealant.

Sound Absorption

1) Does the fibrous nature of your products help with sound proofing? How well does ROXUL sound proof?

ROXUL is designed to reduce sound attenuation through the wall which is the process of reducing the sound energy through the wall. Sound proofing is the process of keeping sound contained in a space preventing the sound moving from one part of the building to another. ROXUL AFB®, SAFE’n’SOUND®, CAVITYROCK®, COMFORTBOARD® 80/110, CURTAINROCK®, SAFE®, and ROCKBOARD® all provide sound attenuating properties. Please see product technical data sheets for specific information. 

2) How much sound can I expect to be decreased with sound attenuation?

Sound “loudness” is measured in decibels [dB]. Sound frequency is the number of vibrations caused by the sound per unit time. The amount of sound decreased is expressed as an STC rating which is a measure of a material’s or an assembly’s ability to resist sound transfer. The higher the STC rating the more noise is blocked from transmitting through a wall or material. The decibel reduction of a wall that has an STC rating of 50 depends on the frequency of the sound. At a high frequency [baby crying, church bells] there may be a reduction between 40 – 50 dB while at a low frequency [bass drum] there may be a reduction of 10 – 15 dB. 

3) How does ROXUL compare to the competition in terms of sound attenuation?

Looking at a perfectly insulated structure which would affect mid-high frequency sound, when compared to fibre glass, ROXUL insulation provides a difference of 3 – 7 dB. However, differences in the installation between products can make an impact on the sound attenuation. 

4) What is the best way to insulate my floors from sound?

There are various methods to insulate floors from sound. Please see our SAFE’n’SOUND®brochure for assembly details (Pg. 4). 

5) Which ROXUL product is best for Sound Attenuation?

The recommended ROXUL product will depend on the application as well as additional components being used. Please contact your local ROXUL sales rep for details on specific product offerings.

6) What are the STC ratings of COMFORTBOARD™, AFB® and SAFE’n’SOUND®?

ROXUL insulation products alone do not have an STC rating, STC ratings are given on an entire assembly. We do provide some assemblies using AFB® that will have STC ratings on them. These can be found in the AFB® brochure.

7) Can I use the board products to make acoustic panels or bass traps?

Yes, board products such as ROXUL ROCKBOARD® and COMFORTBOARD™ 80 can be used to create acoustic panels. Please visit the ROXUL YouTube channel to see a how-to video on creating these panels.

Core Solutions [OEM] FAQ

What is ROXUL Core Solutions (OEM) and how can it help my business?

If you can design it, we can insulate it. Choose from our versatile line of products or work with our team to create a product made for your application. Custom insulation with unmatched performance not only means you get what you want and need, but it also frees up some of your time for those competing priorities.

Who uses Core Solutions (OEM) products?

We work with OEMs across numerous applications and industries. If you’re looking for a testimonial, we have a few to share but just remember, we’re a best-kept secret for a reason.

I require a custom application but I don’t know where to start or which product to use. Who can help me?

We hear you. Finding the right product can be challenging and at times overwhelming. Use this form to give us an idea of what you’re hoping to achieve or give us a call – we’re always happy to talk it through. Either way, you’ll hear from us within 24 hours and we can get the ball rolling.

I’m short on time and need to gather preliminary information as quickly as possible. What’s the best approach?

Use our quick reference guide for high-level product and application information. If you don’t see your application listed, don’t worry. Get in touch and we’ll see what we mcan do to help you out.

How can I be sure ROXUL Core Solutions (OEM) will provide the support I need?

We’ll be there from start to finish and then some. We work with your team through the development process to get your product to market and then after product launch by monitoring and supporting the progress and offering continued support and communication to ensure ongoing success.

Will I have a dedicated sales rep/customer service person?

Absolutely! We’re all about simplifying, not complicating. One point of contact means you know whom to call and can expect a quick response.

I have an idea for a prototype but I don’t want to give away any information that could jeopardize the confidentiality of my product.

Our lips are sealed! We have legal protocols in place, such as non-disclosure agreements, to protect your proprietary information.

I need small batches of specific samples. What’s the process?

We know that samples are critical to your R&D process. We also know that you may need different samples over a prolonged period of time. Contact your dedicated sales representative Jim Miller to discuss the samples you will need, the different sizes available and delivery.

Does ROXUL charge a fee for samples or sample delivery?

It’s important to us that we help you find the right fit first. Samples and shipping are usually free of charge.

I need a price that will work for my product and doesn’t take over the majority of the costs. What does the ROXUL Core Solutions (OEM) pricing model look like?

Prices will vary depending on your product requirements. Talk to your dedicated sales rep to learn more.

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Get in touch for technical and customer support, media requests or to find your nearest ROXUL expert.
Get in touch for technical and customer support, media requests or to find your nearest ROXUL expert.
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