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Frequently Asked Questions

General Questions

1) What is stone wool?

ROCKWOOL 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 ROCKWOOL insulation gets wet?

ROCKWOOL 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.

ROCKWOOL 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 ROCKWOOL products mold resistant?

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

4) Are ROCKWOOL products rodent resistant?

There is no test method to determine whether or not any product is rodent resistant. ROCKWOOL’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 ROCKWOOL make blowing wool insulation?

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

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

ROCKWOOL (ROXUL Inc.) Terms and Conditions regarding Limited Warranty

Here at ROCKWOOL (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 ROCKWOOL has no control over installation design and workmanship, accessory materials or application conditions, ROCKWOOL does not warrant the performance or results of any installation containing ROCKWOOL products. ROCKWOOL'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 ROCKWOOL Products?

ROCKWOOL 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.

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

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

8) How does ROCKWOOL help to earn LEED Certification?

ROCKWOOL products can be used as a contribution to obtaining LEED certification in residential and commercial buildings. ROCKWOOL 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 ROCKWOOL LEED calculator.

9) Does ROCKWOOL Supply Complete Systems?

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

10) Does ROCKWOOL contain formaldehyde?

Standard ROCKWOOL 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. ROCKWOOL AFB®, SAFE’n’SOUND®, and COMFORTBATT® have all achieved GREENGUARD GOLD status for indoor air quality.

ROCKWOOL 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 ROCKWOOL slag contain heavy metals?

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

12) Why are ROCKWOOL batts priced at a premium?

ROCKWOOL 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 ROCKWOOL 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 ROCKWOOL have insulation for Metal Building applications?

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

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

ROCKWOOL products are available through our broad network of commercial insulation distributors. Please contact your local ROCKWOOL 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 ROCKWOOL help designers meet the thermal needs of their wall assemblies?

Yes, ROCKWOOL 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.

18) Can ROCKWOOL be used with direct applied stucco?

ROCKWOOL recommends applying a ventilated stucco system using ROCKWOOL COMFORTBOARD™ 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 ROCKWOOL technical data sheets. ULC Listings are used for Canadian tested assemblies. 

20) Where can we find designs for UL?

ROCKWOOL offers a list of UL designs on the ROCKWOOL 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 ROCKWOOL come in different colours?

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

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

ROCKWOOL insulation should last the lifetime of your building if installed in a properly designed system according to spec. ROCKWOOL 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 ROCKWOOL products?

Off-gassing refers to the gases emitted from a product post-production, often known as Volatile Organic Compounds (VOC's). ROCKWOOL products conform to testing standards limiting the emission of VOC's. For more information, please refer to our technical bulletin here.

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

ROCKWOOL 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 ROCKWOOL 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, ROCKWOOL SAFE’n’SOUND®.

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

Depending on the application ROCKWOOL can make a board product up to 6” thick and a batt product 7.25” thick.  ROCKWOOL 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?

ROCKWOOL 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 ROCKWOOL make custom sized products?

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

29) Can facings be applied to ROCKWOOL 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 ROCKWOOL CAVITYROCK®?

ROCKWOOL Cavityrock® is now available with a black mineral fiber facing for open-joint cladding systems. Learn more about this product or download the technical datasheet.

31) Where can I purchase ROCKBOARD® PG?

ROCKBOARD® PG is no longer available to purchase from ROCKWOOL. 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 ROCKWOOL product?

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

34) Where can I find your Safety Data Sheets?

At ROCKWOOL, we do not use Safety Data Sheets, instead we have opted to use a Safe Use Instruction Sheet. You can find ours here.

35) Is ROCKWOOL batt packaging (Safe’n’Sound, Comfortbatt, AFB) recyclable?

Yes it is recyclable.  Plastic recycle symbol 4 - LDPE (low density polyethelyne).  Please note some municipalities may not be able to recycle the material and customers should check with their recycling centres.

Product Differences

1) What is the difference between ROCKWOOL batt products?

ROCKWOOL 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.

ROCKWOOL 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.

ROCKWOOL 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 ROCKWOOL board products?

ROCKWOOL 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.

ROCKWOOL 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 ROCKWOOL SAFE’n’SOUND® and COMFORTBATT®?

ROCKWOOL 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. 

ROCKWOOL 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, ROCKWOOL COMFORTBATT® is made out of mineral wool and therefore offers some acoustical performance.

2) What fastener would I use with ROCKWOOL 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 ROCKWOOL 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 ROCKWOOL 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 ROCKWOOL products please refer to our Fastener Guidelines. This will give an overview of different fasteners that can be used with ROCKWOOL board products.

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

ROCKWOOL advises to install the cladding as soon as possible after the insulation has been installed, however, if the insulation is exposed and becomes wet, ROCKWOOL 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 ROCKWOOL 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 ROCKWOOL 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 ROCKWOOL 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 ROCKWOOL design guides or contact your local representative for more details.  


1) Can I walk on ROCKWOOL roof products?

ROCKWOOL 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. ROCKWOOL 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?

ROCKWOOL 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. ROCKWOOL 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 ROCKWOOL 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 ROCKWOOL roof boards?

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

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

ROCKWOOL 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. ROCKWOOL tapered panels are available in tapered to zero panels and can help reduce jobsite fabrication. In addition to tapered panels, ROCKWOOL is able to provide additional fabricated accessories such as flute fillers and cant strips. Click here to learn more or contact your local ROCKWOOL sales representative.

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

No, ROCKWOOL 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.


1) How would I insulate my attic?

We recommend the use of ROCKWOOL 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 ROCKWOOL 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 ROCKWOOL insulation by itself?

ROCKWOOL 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. ROCKWOOL offers fire stopping products such as ROCKWOOL SAFE™ to be used as part of the fire protection system. ROCKWOOL 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 ROCKWOOL sound proof?

ROCKWOOL 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. ROCKWOOL 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 ROCKWOOL 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, ROCKWOOL 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 ROCKWOOL product is best for Sound Attenuation?

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

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

ROCKWOOL 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 ROCKWOOL ROCKBOARD® and COMFORTBOARD™ 80 can be used to create acoustic panels. Please visit the ROCKWOOL YouTube channel to see a how-to video on creating these panels.

Core Solutions (OEM)

1) What is ROCKWOOL 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.

2) 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.

3) 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.

4) 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 can do to help you out.

5) How can I be sure ROCKWOOL 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.

6) 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.

7) 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.

8) 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.

9) Does ROCKWOOL 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.

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

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

Building Science

1) Why am I getting condensation on my wall?

Condensation occurs when warm air reaches a cold surface that is below the dew point temperature. 

Dew point temperature is the temperature at which the initial interior air reaches 100% RH.

In the heating season, the interior side of the sheathing (OSB, plywood, gypsum, etc.) is typically the first condensing surface.

In the cooling season, the condensing surface is typically on the interior side of the assembly. For example, the condensation buildup that is sometimes noted on the polyethylene vapor barrier. 

The proper ratio of exterior to cavity insulation, will keep the condensing surface above the dew point temperature and reduces the risk of condensation.   

2) How can I use vapor permeable insulation in hot/humid climates?

In hot and humid climates, inward vapor drive is a concern, especially in combination with reservoir claddings such as brick or masonry.  When using vapor permeable insulation, it is recommended to use a semi-permeable (~10 perm or less) water-resistive barrier on the substrate, behind the insulation. This strategy will reduce the amount of vapor entering the interior of the wall while allowing for drying if necessary.

Refer to the ROCKWOOL™ Hot & Humid Climate Brochure for further guidance.

3) How can you design both a vented or unvented roof (i.e. cathedral ceiling) using stone wool?

Both vented and unvented ceilings can be designed using stone wool. For a vented system, ROCKWOOL COMFORTBATT® can be installed between the roof rafters with a 1” air space at the underside of the roof deck. The air space reduces risk of condensation on the underside of the deck, and can help prevent ice dams from forming. The incorporation of an interior vapor control layer will depend on the climate zone. 

For an unvented system, ROCKWOOL COMFORTBATT® can be installed between the roof rafters in combination with either a smart vapor retarder membrane and/or with the incorporation of a diffusion vent at the ridge of the roof to allows for increased drying. For optimal performance, in an unvented roof, ROCKWOOL COMFORTBOARD™ exterior insulation can be installed above the roof deck, maintaining the sheathing layer at a higher temperature and reducing the risk of condensation.

4) How can you design a sloped roof using stone wool exterior insulation?

For above deck sloped roof applications, ROCKWOOL COMFORTBOARD™ should be fastened to the substrate over a water resistive barrier. To ensure appropriate drainage, a sheet-applied water shedding roof underlayment should be installed over the insulation with a ventilation gap. 

Refer to ROCKWOOL™ Fastener Guidelines.

5) Why do we install polyethylene in our walls and roofs? Is there an alternative to polyethylene?

Polyethylene is a plastic sheet that serves as a vapor barrier to resist diffusion of vapor and moisture through wall, roof and floor assemblies. In some instances, the polyethylene, when taped and sealed, also acts as the air control layer within the assembly. 

The need for installing a vapor barrier depends on the climate zone of the building. In colder climates, an interior vapor control layer is recommended and often required by code.

 Alternative materials include transient vapor retarders, also known as "smart” membranes, that both block vapor and allow for drying when necessary; interior paints with low perm rating; or a vapor impermeable exterior water resistive barrier when no interior insulation is being used. 

Refer to ROCKWOOL™ Vapor Diffusion Guide for more information.

6) How much energy is saved when I upgrade my insulation?

The energy consumption of an entire building is dependent on all the components of the building, considered as a system; including the insulation, window performance, mechanical systems and building use.

Increasing the amount of insulation will decrease the heat flow through that component of the enclosure, and in turn, reduce the heating and cooling demand. Adding insulation can also create a more comfortable indoor environment, when in conjunction with high performance windows. 

Note that the overall energy savings will depend on the building system and the amount of heat flow reduction does not directly translate to the amount of savings (energy or dollars).

7) If I have a vapor barrier on the warm side of the insulation, isn’t that the wrong side in the summer in a cold climate? Is there a potential for condensation?

In most cold climates, an interior vapor barrier is required by the building code. During the summer in cold climates, the vapor barrier would be considered to be located on the wrong side of building.  That said, since the temperature difference between the interior and exterior will be smaller, and the evenings in the summer typically cool down, the vapor drive will be less and for shorter periods of time.

Overall, in most cases for cold climates, the cooling season is shorter than the heating season and less of a concern than consistent vapor drive to the exterior in winter.

Refer to ROCKWOOL™ Vapor Diffusion Guide for more information.


8) When insulating a basement on the interior of recently poured concrete, will there be the possibility of condensation on the poly due to the high moisture content of the concrete? How do I deal with that?

Recently poured concrete has high amounts of built in moisture that will try to dry towards the interior. Placing a vapor barrier on the interior restricts drying to the interior and will lead to condensation on the vapor barrier. 

It is best practice to allow the concrete to dry for a period before installing a vapor barrier.  Additionally, the use of a smart vapor retarder membrane will allow inward drying for the lifetime of the building and is recommended when insulating the interior with vapor permeable insulation. 

Refer to ROCKWOOL™ Vapor Diffusion Guide for more information.

9) How do I calculate the dew point of my assembly?

The dew point surface refers to the location within the wall that is below the dew point temperature with risk of condensation, based on static interior and exterior conditions. 

ROCKWOOL™ Building Science team offers dew point calculations to designers and transient heat and moisture transport calculations in walls. Please visit ROCKWOOL Building Science™ for a list of services offered, and contact form.

10) What is the difference between being airtight and vapor tight?

An air barrier and vapor barrier has different control functions within an assembly.

The purpose of an air barrier to is limit the amount of air that passes through where the vapor barrier is to limit the passing of water vapor through a material/assembly.

An adequate air barrier system is comprised of an air barrier membrane, plus tapes, seals and accessories to ensure complete air tightness. A vapor barrier is typically a single layer with a low perm rating. The vapor barrier does not need to be sealed to function adequately. It is important to note that air control is more important than vapor control; moisture transport by air is significantly higher (~100x) than moisture transport by diffusion.

In some cases, the vapor barrier also acts as the primary material in the air barrier system. Additionally, caution should be noted when designing with low perm insulations and materials to ensure a double vapor barrier is not created within the assembly.

Refer to ROCKWOOL™ Vapor Diffusion Guide for more information.

11) How do I calculate effective R-Value or assembly R-Value?

Every material or layer in an assembly has a thermal resistance, known as R-value. The R-value has a direct relationship with the material’s thickness. The sum of all material R-values is the total nominal R-value of the assembly, including surface air films. However, the total effective R-value of an assembly is the total nominal R-value minus reductions caused by thermal bridging at the studs, girts, fasteners, ties and other attachment methods.  

Visit the ROCKWOOL™ R-Value Calculator contact ROCKWOOL™ Building Science for assistance with your calculations.

12) Can you offer exterior wall analysis (WUFI)?

Yes, along with other services, ROCKWOOL™ Building Science offers moisture analysis for wall and roof assemblies using WUFI®, a one-dimensional hygrothermal modelling software designed to calculate the simultaneous heat and moisture transport in multi-layered building components. This analysis predicts the hygrothermal performance and related durability risks of an assembly, using actual climate data and parameters for the specific project location. 

Please visit ROCKWOOL Building Science for a full list of services offered, and contact form to get in touch with our building science specialists.

13) Window and Door penetrations – Where can I find tech assistance regarding continuity of thermal, water and air control layers?

Many of the ROCKWOOLTM brochures are quality resources that provide example details for windows, doors and penetrations intended to assist the designer, contractor and homeowner.

Contact ROCKWOOL™ customer support, available daily from 8:30 am EST to 5:00 pm EST Monday to Friday, to answer any questions.

14) Do you have any information to share on the thermal bridging effect of fastener types?

The ROCKWOOL™ Fastener Guidelines Guide provides information on thermal bridging effects that is third-party and industry validated, for different types of fasteners and attachment methods.

Contact ROCKWOOL™ Building Science for further inquiries.

15) What is the ratio of exterior to interior insulation that I should use to ensure the dew point is on the exterior?


The level of exterior insulation required to move the dew point to the exterior side of the assembly will depend on the assembly type, insulation type specified, and climate. As a best practice rule of thumb, a minimum exterior to interior R-value ratio of 3:1 should be applied. 


For further information and guidance, please contact ROCKWOOL™ Building Science.



16) What type of water resistive barrier is best to use with exterior stone wool insulation?

To benefit from the high vapor permeability of stone wool exterior insulation, it is recommended to be used in combination with a vapor permeable water resistive/air barrier membrane on the exterior side of the sheathing. Note, ROCKWOOL exterior insulation products do not require protection behind open-joint claddings. 

For further information and guidance, please contact ROCKWOOL™ Building Science.


17) What is the difference between stucco an EIFS?

Stucco is an exterior finish made of cement and plaster that is applied in 2-3 layers, with a wired mesh/lathe, installed directly over the wall substrate. While ROCKWOOL™ exterior insulation can be used in combination with stucco, it is not recommended to install stucco directly over the insulation without a drainage space.


EIFS stands for Exterior Insulation Finish System. It is an integrated non-load bearing exterior cladding system that includes an insulation layer, water resistive barrier and finish.  ROCKWOOL™ does not offer an EIFS system in the North American market. However, ROCKWOOL™ stone wool can be used as the insulation component in EIFS systems as offered by EIFS manufacturers, particularly when non-combustibility is required.


For further information and guidance, please contact ROCKWOOL™ Building Science.

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