Roxul Safe’n’Sound® insulation is a semi-rigid, mineral wool batt insulation designed for interior wall partitions, floors, and ceilings in wood and steel frame construction. It offers superior fire resistance and acoustical performance, making living spaces warm, energy efficient, and compliant with modern building standards. Roxul insulation is designed to fill perimeter gaps between walls and provides fire-stopping and acoustical properties.
Rockwool, also known as mineral wool, is a material typically used for noise reduction and insulation in both commercial and residential settings. It is touted for its fire-stopping properties and is not intended for thermal applications like insulating exterior walls or attics. The optimized density of Roxul Safe’n’Sound compromises its ability to prevent heat loss.
While it does a better job than fiberglass, it cannot be considered a sound-proof product. Roxul Safe’n’Sound is specifically designed for soundproofing and is not suitable for thermal applications like insulating exterior walls or attics. Rockwool Comfortbatt is not faced, making it not appropriate for exterior applications.
Installing Roxul insulation depends on the type of insulation needed. For example, Roxul Safe® 45 is a semi-rigid stone wool insulation board ideal for fire stopping in concealed spaces of multi-unit residential buildings. However, it is not suitable for exterior applications due to its lack of a moisture barrier.
In summary, Roxul Safe’n’Sound® insulation is a lightweight, semi-rigid stone wool batt insulation that provides fire-stopping and acoustical properties for interior walls, floors, and ceilings in residential wood and steel structures. It is not suitable for thermal applications due to its optimized density and lack of moisture barrier.
📹 3 Places You’ll Want to Insulate + Rockwool Advantages/Overview
Huge thanks to our Show sponsors Polywall, Huber, Dorken Delta, Prosoco, Rockwool & Viewrail for helping to make these …
What kind of vapor barrier for exterior walls?
Class I barriers are the most impermeable, with a rating of 0. 1 perms or less, and are best for cold or humid climates. Class II barriers, with a perm rating between 0. 1 and 1. 0, allow moisture to pass through, and are suitable for various climates and uses. Class III barriers, with a perm rating between 1. 0 and 10. 0, are the most permeable and are typically used in milder climates or as part of a moisture management plan.
Does Roxul need a vapor barrier?
ROCKWOOL solutions, which are water-resistant, can be installed with a vapor barrier to prevent moisture from entering ceiling spaces. This is especially important for basement and cellar ceilings in newly renovated below ground spaces, which can be transformed into comfortable living areas. Additionally, stone wool insulation can improve fire performance, making it crucial for private housing and public underground spaces like parking garages.
Can you use Roxul insulation on exterior walls?
ROCKWOOL ROXUL Safe® 55 and 65 are medium-density insulation products designed for interior and exterior firewall applications requiring fire resistance of at least 1 hour. These products protect the building envelope, covering the largest surface area, and prevent heat loss through poorly insulated walls. ROCKWOOL external wall insulation enhances living spaces’ warmth, energy efficiency, and compliance with modern building standards, while also providing acoustics, indoor comfort, and fire safety.
Can you use safe and sound insulation on exterior walls?
Roxul Safe n’ Sound is designed with a specific focus on soundproofing, rather than thermal applications such as insulating exterior walls or attics.
How do you soundproof exterior walls?
The exterior wall’s Sound Transmission Classification (STC) rating is typically in the mid-30’s to mid-40’s. To improve soundproofing, add a layer of 5/8″ drywall with Green Glue Compound or 1 LB or 2 LB mass loaded vinyl (MLV) over the existing drywall and cover it with a new layer. This will increase the STC rating to the low to mid-50’s if the wall is 24″ on center framing. The MLV will bring the wall rating into the mid-40’s or higher, regardless of stud spacing.
The best bang for the buck is a second window added to the existing window frame with Green Glue Compound or MLV and an additional layer of drywall. If the wall lacks windows or doors, consider upgrading using double stud framing technique or resilient sound clips like the GenieClip® RST or HushFrame Rafts. These options offer immense performance for all frequencies in a wall without windows or doors.
What is best insulation for exterior walls?
In cold climates, closed-cell spray foam is the best insulation for exterior walls due to its high R-value per inch, which effectively resists heat flow and serves as an air and moisture barrier. Insulating exterior walls from the inside is possible, often done in existing homes where exterior modifications are impractical. Options include blown-in cellulose for filling existing wall cavities and spray foam insulation for excellent air sealing. The R-value of the best insulation for exterior walls varies by insulation type and wall structure, and it’s beneficial to choose an R-value that meets or exceeds local building codes.
Typical R-values include fiberglass insulation (R-13 to R-15 for 2×4 walls, R-19 to R-21 for 2×6 walls), foam board insulation (R-4 to R-6 per inch), spray foam insulation (R-6. 5 to R-7 per inch), andcellulose insulation (R-3. 5 to R-4 per inch).
Do I need a vapor barrier on exterior wall insulation?
Building codes mandate the use of vapor barriers with insulation to improve indoor environmental quality and energy efficiency. Building scientists recommend this method, as it protects against diffusion. Polyguard recommends a quality air barrier system to limit infiltration, exfiltration, and moisture accumulation in the building envelope. Contact Polyguard professionals for more information on when to use a vapor barrier with insulation.
What is the best type of external wall insulation?
Mineral Wool offers superior thermal, fire safety, and acoustic performance in external wall insulation. It is typically finished with a render coat and is crucial for achieving the desired level of thermal performance. The finish should be suitable and the insulation’s fire classification reaction should be considered. Rock Mineral Wool insulation offers both thermal and acoustic performance, making it non-combustible.
How can I soundproof my house from the outside?
To reduce noise pollution, start by inspecting your exterior walls for cracks or holes and filling them with acoustical sealant. If possible, update your home with vinyl siding to bounce noise back towards its source. Insulate your walls with soundproofing insulation to create a thicker, more absorptive barrier. Soundproof doors by installing weatherstripping to keep most air and noise out, but some doors may need extra help. If light peeks through, install door seals or sweeps to fill gaps.
Soundproof vents, ducts, and crawlspace by ensuring that air conditioning systems do not direct outside noise into your room. These measures can help create a more comfortable home environment and reduce noise pollution.
What is the difference between ROCKWOOL and Roxul?
Roxul Insulation, a subsidiary of Rockwool Insulation, has recently rebranded in North America. The mineral wool insulation, which is still available in Canada, is widely used by homeowners for insulatement and home upgrades. When professionally installed, Rockwool insulation can significantly enhance energy performance and comfort. The material, made from stone fibres, naturally controls moisture, making it a popular choice for insulate homes and commercial buildings. To learn more about Roxul and Rockwool products, or to request a free evaluation of your home, please fill out the form provided.
How do you soundproof an outdoor area?
This article provides tips for outdoor soundproofing, including installing a soundproof fence, installing outdoor mass loaded vinyl, and making the right choices to have a quieter backyard. Outdoor soundproofing doesn’t have to involve building a new structure to block road noise or loud neighbors. It can be achieved by using products like reinforced MLV for outdoors, which are solid and flexible.
Planting trees or a wall of hedges won’t be effective as they don’t provide a solid covering, leaving gaps for sound to travel through. Instead, use products like outdoor mass loaded vinyl to block outdoor noise effectively.
In summary, outdoor soundproofing is a crucial aspect of maintaining a quiet and peaceful backyard. By using products like soundproof fences, mass loaded vinyl, and making the right choices, you can create a quieter and more peaceful environment for your outdoor gatherings.
📹 Do Not Use Rockwool To Soundproof Walls
Many people come to me saying they will use Rockwool to soundproof their walls. First, this is not really necessary. Second, if you …
I really like using Rockwool. For those that haven’t it is exactly like Matt says he isn’t embellishing it’s qualities. My only complaint is that it is super itchy and make sure to wear a good mask during install as you will inhale the small fibers and you will be coughing it up for a while afterwards. I have it in the wall between the living room and master bath and I can turn the surround sound way up and you can barely hear it. My only complaint is that some of the products are kind of a pain to get in small quantities. It is far superior to the old mineral wool that was popular back in the 50s to 60s. That stuff was very poorly manufactured by a company here in Texas. The batts were undersized and lots of granular slag left overs in the batts and in the loose attic insulation.
Another benefit to rockwool is its end of life use. I operate a gravel pit and often take soil from building sites for pit remediation. Not long ago i received a number of loads from a recent home demolition. The crew had done a good job of separating concrete, siding and all other debris from the soil however the material was scattered with pieces of foam. Touch foam insulation with an excavator and you instantly have hundreds of bits of foam board which can not be separated from the soil and that foam is there as a pollutant for hundreds of years. Rockwool on the other hand can be used as a soil amendment I understand that it can even be used in organic potting soil. I used spray in open cell foam in my latest renovation but from now on will stay away from plastic foam products or at least do more research on the products I do use
When I purchased my home here in NC I was told that there was plywood under the aluminum siding. Well, it turns out that I only have very thin sheathing board and the aluminum siding. (Fun.) And a home that was supposed to be constructed with 2 by 4 with 16 on center construction seems to vary in width between studs. (More fun) I appreciate the info as I seemingly will need to “rebuild my home in place. I recently used Rockwool to insulate between a bathroom that has a laundry space included.. I’d love to make my way around the house with the product. Thank you again for your articles!
Rockwool is the best. I used it for fire break and sound proofing between walls and ceiling during our rental suite reno and in the exterior walls. Sound was no longer an issue in the house! (We did use double layer and rez bar). Heating cost in the rental dropped 50%. We had a water pipe burst a year after the reno and when we opened the wall, the insulation had drained completely and was dry using a meter the next day. Studs retained moisture much longer so we used a dehumidifier for that. The insulation is so easy to install because it maintains it’s shape and doesn’t flop around. Great stuff!
just redid a kitchen, we layed metal studs with 5/8 sheetrock and rockwool . it was sufficiently strapped to handle the weight on the ceiling My late father put rockwool and 5/8 sheet rock throughout the house before the days of youtube :), so I had to follow through in this remodel. So happy to discover how much he thought of after the fact 🙂 🙂
What are the benefits/cost difference between using Rockwool or ZIP-R on the outside of the house? Considering building, and I live in Ohio. I had been seriously considering ZIP-R until this. Is ZIP-R vapor permeable or do I need to worry about that if it is essentially a vapor barrier on the outside of the house? Vapor transmission/buildup is a big concern for me in the climate zone I live in. Great content, thank you for all of the valuable information!
I guess no one around here carries that brand. Need 2×4 at 24′ on center in either 11 or 13 but when I pull up the home stores (about 7 of them) only one carries it and only one style. I am doing the rafters on my detached garage and don’t care if it is pink, blue, grey, or silver. My garage rafters are not the standard 2×6 so after installing baffles I am left with little space but I plan on getting rolls or batts that are 11r or 13r and pressing them in. The foam boards seemed expensive and the silver covered bubble wrap did not seem like the right then either.
I am building a house in Central Kentucky. I have a daylight basement with two concrete walls, ten inches thick, earth exterior. I want to use an alternative insulation to foam, and want feedback on using the Rockwool insulation in lieu. I already have stud walls (16 on center) along the concrete walls. I cannot use the exterior product against those same walls. Can you give me some feedback on Rockwool against a concrete wall. Again a day light basement. I will have geothermal as my heat and cooling source.
First I’m a big fan of your articles and feel like they hold a lot of useful info. I’m currently planning on building a new home, I’ve seen this product in past articles and it has really intrigued me. However (and I do realize that they are your sponsors), as stated in a post above, RockWool does use formaldehyde as a binder in the manufacturing process. Even though their claim is that most of it is burnt off in production, what makes this product superior to competitors similar products that are formaldehyde free?
It’s a shame they don’t have some type of blown-in product for attics. I understand you would lose the “compactness” of the product but I would think they could engineer the product so it’s in real small “chunks” that would settle close together. I want to remove my blown in white insulation in my attic and would really like a better, more dense product. Any ideas?
I use Safe n Sound in the wall between laundry/mech room and the media room. The safe n sound absorbs a wide range of the frequency band. My walls are double 3/4 inch sheet rock on each side with gleen glue between. I can have a full load of laundry going,, water heater running, and furnace blowing and its still quiet in the room.
Thanks Matt for introducing me to the product. I like the sustainability part of it a lot! Question on how it works from a water vapor perspective. You did not mention if it needs a moisture barrier like regular insulation does and does not appear to even be an option to order it with a moisture barrier. I am looking for something to insulate my lath and plaster walls on my 100 yr old SoCal house. This seems like a good candidate.
Rockwool hilarious when I saw it in title . I had to comment on this . I used to grow the best weed using rock wool ten years ago hydroponically. The best weed is always hydro grown out of rock wool, compared to today’s crap soil grown. And bugs will crawl in it through it if it stays wet . And it stays wet if water gets on it and soaks into it and water source isn’t fixed. But insulation value is one of the highest value like he says
Great article. I live in the northern midwest and want to insulate my detached 2 1/2 car garage so I can try and do work in it during the winter months. I know when it gets below freezing it will still be a challenge to work in without a heater, but how can I keep it “warmer” than the outside? What product is best (and R value)? I don’t have drywall, just studs for now. It does have an unfinished peak meaning no false ceiling and an attic. Also, is there something I can do to the concrete slap to improve warmth? Thank you.
Hi Matt, I really enjoy your show. I’d love you to cover aerogel insulation (pros/cons, cost, etc) and even compare it to other great insulation products like rock wool or air krete for example. I’m trying to learn more about the best insulation choice for R value, fire and water resistance and sound proofing and there’s not a lot of information about aerogel yet.
I’m a remodeler in Hampton Roads area of VA. Seeing many houses from the 40-60’s I can say that over time the one of the issues I see as a remodeler on these older homes is the shrinkage and failure these many other types of insulation. If Rockwool won’t shrink over time then I’m SOLD because it won’t FAIL!
Great show Matt! Question… I have two temperature controlled chicken coops. Well as controlled as they can be uninsulated. You mentioned rockwool is sound (we got a couple roo’s), mold, and bug resistant. Any thoughts about how well this would work for this application in regards to all concerns listed above? Seems like I wouldn’t have to run two 8000btu A\\C’s ( that have issues keeping up in the summer) constantly, or 15 – 250watt heat lamps during the coldest January winters (that struggle to keep the temp at 68 to 74 when it’s below zero). The coops are pretty tightly built with weather proofing with air exchange fans, and everything is automated. I would just love to see my heat/A/C’s work less often, keep the noise of the Roo’s down for my neighbors, not have the structure rot from any water that’s absorbed by insulation, not give a new home to bugs or rodents…. Seems like I’d save more money in the long run, and I’d cover the walls with thin ply wood and maybe tape the seems. ( I’m not worried about the floor rotting, that has a moister barrier on the bottom, and a large pond liner on the inside and is cover in wood chips for bedding and insulation). Thanks for any thoughts in advance. (P.s. to anyone with concerns about the use of heat lamps or a/c’s…. I am a long time farmer, the insurance company, Fire Marshal, and animal control all approve of our set up….please don’t judge.
would love t see you do a article on two less common insulation types here in north america. Those would be rigid wood fiber insulation (like Gutex) and wool insulation. Both have very good characteristics/qualities and from my perspective cost and availability are their main drawbacks. There is however a company in Maine working to open a rigid wood fiber insulation plant and there is a company in Oregon using processing domestic wool for insulation.
Hi Matt, I live in Saint-Leolin, NB. We were to build in ICF either Polycrete or Nudura (ground walls were build with Nudura). Then because I was not home due to work and concrete cost, we hired a wood construction worker. We build our house last fall and everything burned down before X-Mas due to a cigarette butch. We are rebuilding and everything with Rockwool outside/inside. Question: how do you apply the outside finition to the 2″ matt Rockwool? Thanks
Matt, I’m glad to hear that you are working with some builders from California. The desert southwest is a totally different animal, as far as insulation strategies go, than the North, South or East. I live in northern Nevada and we have cold, dry winters and hot, dry summers. Please give some insulation strategies that will work better in these type of climates. We feel left out!
I wonder if there is any evidence affirming the safety of Rockwool to humans. There are some parallels between Rockwool and asbestos, including the fact that the fibers can become airborne and lodge in the lining of lungs and the materials are inorganic. Inorganic substances can be difficult for the human body to purge. Even small amounts of this material could cause harm to humans, and particle masks are not foolproof. This concern is really worth addressing because homeowners and builders should know the potential risks of using this material so that they can make an informed choices. Sorry to sound alarmist, but the risk of filling the wall cavity of a home with a potentially dangerous substance is a valid issue when home building decisions are made.
matt, just started perusal your vids, they’re pretty great. i live in the deep south-‘west’ (south texas) so it’s pretty hot here. i live an hour from the coast and we have hot humid weather. i’ve read that in our climate zone, a vapor barrier isn’t necessary on the insulation face and just have 4 or 6″ bats in the attic ceiling (not roof). i’d like to insulate our 2×6 roof and was planning on ripping more 2×6’s to extend my existing 2×6’s to ~2×9’s and adding R-30 mineral wool bats between w/ a 1.5″ gap between pitched roof deck and insulation. should i include a vapor permeable radiant barrier within that air gap? any additional or alternative advices like keeping 2×6’s puting 4″ bats and covering the whole deal w/ like, 3″ of comfort board?
Found your articles and have become a big fan. I want to Install Rockwool R30 insulation in the garage attic above my new wood shop as I am also installing a mini split unit to co trip climate here in Central Florida. I have been looking for mo the and no one seems to have the R30. How can I find it if you know?
I like rockwool, but price point comparison with cellulose is huge….just can`t justify that extra expense……..of course with exterior insulation its really the only choice as foam has some major drawbacks…..do a episode on cellulose insulation. Double wall, staggered studs and cellulose is a powerful and cheap alternative……..plus it has some cool attributes beyond the standard R test, such as eliminating laminar flow in a wall cavity…a huge problem with fiberglass bats.
I have a problem that I think Rockwool may be the answer too…my sump pump is located directly beneath my 6 month old babies bedroom and when it ejects at night it wakes him up from the sound and rumble it makes ejecting…I thought about using the Safe N Sound in between the joists…any other cost effective ideas on top of this Matt? Much thanks in advance and hopefully some sleep!
I put 2 layers of 3.5″ Rockwool R-15 batts in specific attic ceiling areas to replace 12″ of blown in fiberglass after some renovations. Summer hit and now midday sun the ceiling with 2×3.5″ Rockwool batt area of ceiling is 73F, blown-in fiberglass areas are warmer to touch and measure 75-76F, while the AC thermostat is 72F. That’s poor results for all that blown in fiberglass. Looking forward to using more of this product as I reno more.
Was considering use the insulation for my pipes water connections That said… could the comfort board be painted and exposed to Ohio elements? I live in a mobile home in Ohio and didn’t know they made this board until just perusal your article Was thinking would replace my skirt with a product like the board you just showed us
important thing to notice that Rockwool is water resistant and permiable not water proof and that rated 1liters per sq. meter still has to be accounted for even if the material doesn’t soak it for the long term, remember that ventilation with these. Biggest difference to XPS foam board is that XPS is virtually water and vapour proof when you glue seams with non expanding urethane imo. best practice for cold climate is to put XPS in the inside for heat and vapour barrier and rockwool on the outside since Rockwool can also be plastered over with a mortar cement.
Mr. Matt, I always enjoy your vids & learn something new & exciting every time. My Builder/Structural Engineer Husband who usually handled more of the technical/materials/math/best practices, was killed before we had a chance to finish our basement on our new construction home. *guess I did more manual labor & coordinating with him. It’s all roughed-in, but it seems there’s still so much to do. We physically built our houses together so I should’ve paid closer attention. 😞 Now I’m not sure what to do w/o him and I don’t have much luck with subs showing up, not being kinda creepy &/or listening to me (unlike HE did). Now I’m trying to finish it (or parts of it I can afford) myself as much I can (no choice I guess) . So I’m gonna try to do it myself, even if die trying. 🙏 Prayers appreciated.🙏 He had already started to install safe n’ sound Rockwell insulation in the basement ceiling under the the main floor so I’ll order more & finish that part. Looks like we still needed to insulate the basement rim joist too.🤦♀️ Lots of how to vids on rim joists tho. QUESTION: Can Rockwell safe ‘n sound be installed ON our daylight basement POURED CONCRETE VERTICAL WALLS (with or w/o some kind of vapor barrier???) OR should I just stick to using foam boards for that (& what kind of foam boards, glue tape, etc….that’s NOT the MOST expensive) on the vertical concrete walls??? Spray foam is out b/c $$$$$$. 😞🤦♀️ Any advice you could give would be greatly appreciated.
Thanks Matt huge fan of yours just looking for some insight on roxul vs spray foam …I’m in the northeast region and am currently finishing my below grade basement …. we have three windows in the space for ventilation and no moisture issues and was thinking on closed cell spray foam directly against my poured concrete foundation but for the ceiling was wondering if you would do a) closed cell b) open cell or c ) Roxul
Hey Build Show, love the emphasis on exterior insulation. It makes so much sense. I was wondering if you could share how you handle inswing exterior doors when using deep exterior insulation. In my experience as a building material supplier, door manufacturers are limited in the depth of sill that can be offered on inswing doors. Particularly with 2×6 wall construction and 2″ of exterior insulation. Required jamb/sill depths would require 8-9/16″ or greater to allow for 180 degree swing of an inswing door. Have you had any challenges that with this? How would you detail these door sills?
Matt is correct in his assessment of this product. It is the only type of interior insulation that should be allowed in U.S. home construction as far as filling the cavities with other than foam. Foam is risky if not installed properly, and it is not a DIY product in my opinion. I have installed a lot of fiberglass insulation in projects over the years, none even come close to this product. It completely fills the void, cutting is easy and precise around outlets. If you want to build a structure that requires less energy to heat and cool this product is the essential product to get you there. It is not cheap, but there is no doubt this product is going to pay you back in energy savings and the increased noise reduction is just an added bonus, as is the increased fire protection and the fact it will not absorb water. This product is hard to find, must be ordered in special order, but is worth the extra effort. Thank you Matt for bringing this product to the attention of so many people.
Hi Mat. perusal more daily. In this article at 4:03 into it you show a roof system with Rockwell that also looks like it is venting the roof as well. Which article would that be? I will be building a timber frame this spring in northern N.H. Looking for the best roof system to go with. Any advice on your articles would be greatly appreciated. Great articles! No wasted time,to the point, loaded info and explained very well. Thanks Tim
We used about 7 pallets of the different forms. They are all basically the same item safe n sound is a little denser, the r30 is 2 r15 molded together. Makes you itch for about a week no smell, particles should be swept up after all insulation is done if it gets embedded into drywall then painted over you will be left with a rust spot in a few months. Reduces,ore of the higher pitch sounds mid to lower bass sounds can still come thru by stud transfer
Since Rockwool sheds water and is vapor permeable would it be ok to use it again the roof deck between the rafters? I am working with a state program to redo the old insulation and get to code, they will not do spray foam. I have breathing issues and would prefer not to use fiberglass or cellulose blown of any kind. I lice in MD Eastern shore too.
I am about to build a home in the panhandle of Florida. It is a single story structure on slab. The builder is using cardboard in the eves at the end of the insulation bats in between each rafter. I am concerned about moisture, and mold over time on this cardboard. I think the purpose is to keep the insulation from blocking the air flow from the soffits to the ridge vents. I have photos showing the cardboard. Anyone have any thoughts?
I swear I saw you talking to someone in an attic and it looked like they had rock wool right up against the roof sheeting. Meant to go back and review what you said about that but can’t find the article. Are there any vapor concerns with rock wool directly in contact with sheeting in that application or does it pass vapor effectively enough to not rot out the roof from the inside?
Hello. I was wandering if someone reading this comment could answer my question pretty please. I live in Des Moines, Iowa. Aka cold winters and hot/ humid summers. I am going to have my siding AND old crappy sheathing removed on my house (due to a hail storm). Can I install RockWool in my 2 x 4 stud bays and NOT have to worry about adding a vapor varrier??? RockWool does not come with a vapor barrier and fiberglass insulation does…. sooooo am I correct in understanding that RockWool doesn’t require a vapor barrier even in cold climates??? Thank you if anyone knows the answer.
Hi Matt ….here from the southern hemisphere… Learned a lot from you website… smart ideas and specially how bad is being build here… Anyway. A question Farming in Austin is engineering wise ” easy”… but the must be a significant difference in California… / west coast because of the earthquakes…. Looking forward to comments
I am getting ready to insulate my woodshop as soon as the electrical is completed. I have been considering closed cell spray foam (to close in the gaps….long story) and then install batt insulation. After seeing this article I am thinking about putting the Rockwool on top of the spray foam…thoughts???
Hello Matt I have a question I’m assuming that you don’t answer back on your comments, but I will take a chance anyway. I live in NJ anyway I have a attached garage, and I bought rock wool to insulate my garage. On the living side do I need a vapor barrier, and if so I would I accomplish this if the living side is already sheet rocked?
Twenty year claims adjuster here and I know I’m going to tick some people off, but house fires are not that common. All of the hand wringing that goes on over “fire resistance” is a waste of money. Get several quality smoke detectors in your home and quit wanting to “slow down” a fire that has about a .005% of ever happening. Also, a partial burn is way more headache for the homeowner and claims adjuster. Have the thing burn to the ground, get your check and start from scratch.
Hey Matt keep up the good work I am a big fan of your shows and use your commentaries with my clients to explain the pros and cons of all types of building materials and building processes . I enjoy your humble approach to failure anyone that builds at times will run into a oversight in applications . With a good attitude failure can create a determined state of mind to get it right . We are all desperately want to avoid catastrophic failure whether financial or structural life threatening disasters . Your program is part of my Continuing Education after 38 years building new and renovating old houses . Cheers
Matt, after the first article I saw on Rockwool, I changed to Rockwool for the insulation on the addition I am building. Love the product. It’s hard to find in Northern Wisconsin, but I finally found a wholesaler who had enough in stock. Now I have to decide if I want to put comfort board on the exterior. Thank you mat for educating us. You’re doing a great job. “Walk with the KING and be a blessing.!”
I’ve heard rockwool compacts after a while. Are there instances where this might do this, and why? Wished comfort board came in a 2″ thickness for tiny homes on wheels. Have a trailer I want to redo, this would ge perfect for the exterior if it was in a 2″width, because then it would be in under 8-1/2′ wide.
I just built a wall in a financial office to divide the room, used 5/8 WB, Acoustical Sealant, Rockwool Safe & Sound, and an exterior door, the 2 rooms are dead quiet, they can talk on the phones and not hear each other, and the client is very happy. Great product knowledge I learned from Matt, thanks buddy keep up the great work!
I needed to add a bedroom and decided to subdivide the “man cave”. Because of all the potential noise in the common area, I decided to insulate the bedroom walls with Rockwool. It has done a fantastic job reducing the sound transmission. It was intended to be a temporary room, but it turned out so well I’m planning to make it permanent. It was my first time installing Rockwool and it was a bit more fragile than I expected. They do well most of the time, but if you’re too rough with the batts they will break apart. It is convenient though for filling in small, odd shaped spaces and working around wiring. It was also dustier than I expected and a little itchy. I agree a mask, gloves, and long sleeves are a good safety tip. I am looking at building an age-in-place home (at least 40 years) and I’m definitely considering it for that project. Up here in the northland I’m looking for energy efficiency and low maintenance. One thing Matt didn’t mention is its mold resistance, mostly because it doesn’t absorb water.
The casual “information” presented re: sound control is mind-numbing deceptive and or ignorant. I took architectural acoustics from one of the best in the world (the late Robert Newman of BB&N) at MIT, in the 70’s. As a builder since, I have done many projects with sound attenuation (there is no such thing as “soundproofing” in residential construction). First thing you need to know is that insulation within standard stud wall cavities has a negligible effect (that is being kind), and serves mostly to make money for the insulation contractor and manufacturer. Stagger studs is the only way for the insulation to be effective. This is because the physics of sound transmission can be thought of as akin to thermal transmission, wherein the “bridging” is the rate-determining step. Sound impinging on one wallboard surface of an assemble creates an energy transfer to the opposite wallboard surface, by way of the mechanical coupling through the studs, and the sound energy is re-radiated out into the adjoining room, visually undiminished. The airborne energy has little or no contribution to the energy based to the opposite surface. If you visualize the standard wall as a honeycomb structured speaker cone/ diaphragm, you are on the way to enlightenment. BS is good if you want to sell product, but not too helpful when dispensed to an ignorant lay public. The “quiet tunnel” can be easily achieved with any absorptive material, but the key point is that there is no hard surface (wallboard) applied over the dampening material, which would then deny adsorption: totally bogus demonstration.
I use Owens Corning Fire and Sound. The R value is 15 for a 3.5 inch thick batt. I have performed experiments with R13 fiberglass batt vs the Owens Corning product. Despite the nearly equivalent specifications for STC improvement within standard gypsum walls and NRC specifications, the Owens Corning mineral wool insulation provided a 7 dB greater reduction of noise transmission through the wall, at low frequencies. (<500 Hz)
FYI – my personal experience. In process of building our house, I went ahead and put in safe n sound between the bathroom and our bedroom.. and only put fibreglass between the den wall and the same bathroom. It may be technically not much of a difference, but the actual experience of it day to day is huge. I can hear someone talking or listening to music in the bathroom from the den.. and nothing at all in the bedroom. Wall thickness and open cavities between walls is extremely similar and the same drywall was used, but the audio experience is very different… there could be many explanations, but the 30% cost difference is well worth it. I do not know of the cost to build in other parts of the world, but here in Canada, the difference in cost is a rounding error on a build.
There’s some big factors you’re leaving out immaterial of sound. Rockwool is expensive, yes, but it has numerous advantages over fiberglass besides a little sound difference. Rockwool is fireproof up to 1000 degrees, it doesn’t smoke when heat is applied, it’s water resistant if it gets wet, it’s easier to handle, and rodents don’t like it. Those are all pros that fiberglass insulation doesn’t have. Fiberglass will shrivel up under water, it will smoke and catch on fire, it’s itchy as hell, and rodent’s absolutely love it and make nests in it. So while the sound difference might not be huge, there’s really no comparison as to which is the better product overall and why it commands a premium over fiberglass. For me, I’m willing to spend the extra 40 cents per foot to keep my family safe and possibly prevent my house from burning down. I know this article is about sound, I get that, but it might be something you at least touch on as a difference.
Info from Rockwool below: “thermal resistance (R-Value) of ROXUL AFB® when tested to ASTM C518 “Standard-Test Method for Steady-State Thermal Transmission Properties By Means of the Heat Flow Meter Apparatus”, the thermal resistance is R4.1 per 1″ thickness. Although not branded, the R-value for the ROCKWOOL SAFE’n’SOUND® is R11.7 for the 3″ batt.” As stated in the article, it’s not branded or labeled because it is for interiors and lacks a moisture barrier and the appropriate density to function as an exterior insulation.
Rockwool insulation’s R value is 3.0 to 3.3 per inch compared to 2.2 to 2.7 per inch for Fiberglass. While Rockwool is noticeably more expensive it does provide far better insulation value than Fiberglass, by almost 30%. Rockwool also has a higher STC rating (45-52) than Fiberglass (33-39). It appears that you are skewing your results to justify the lower cost.
Don’t listen to this advice… This is the difference between Academic Theory and Real World Experience/ application (Wisdom wins out against education)… for the cost of using mineral wool insulation your benefit is very noticeable (I agree that “Rockwool Safe ‘n’ Sound” is a marketing gimmick, but installing the densest mineral wool you can afford will make a noticeable difference)… and on top of that; it improves your homes fire-safty.
You really do not compare Rockwool to OwensCorning here. You basically say that it is expensive which is what we all know already. If you really were comparing the difference then you would build those 6 example walls in a room and test them with the Fiberglass insulation or mineral wool. My own experience with Rockwool is that it has superior sound deadening qualities when compared to Fiberglass in regular walls and floors. I also thought that it was odd that you did not compare a simple wall with insulation with 2 layers of drywall. That would be, by far, the cheapest that you did not test and what many contractors do in quality apartment buildings.
Rockwool is marketing the hell out of Safe n Sound, and that marketing has been very effective. I am in several home theater groups, and every time soundproofing comes up, people will recommend Rockwool for soundproofing, even though experts have been saying for years that fiberglass works just as well inside a wall cavity.
Thanks for the article. Very informative. I believe you misspoke when you said, “doesn’t have an r-value” at least twice. Building materials have R-values. A sheet of glass has an R-value. I think you’re just trying to say that it’s not indicated on the packaging, not officially rated, and it would not be OK for an inspector if used for attic and exterior walls. It does have an R-value of about R12. So in specific use cases, like interior walls, or in area where you didn’t care whether the inspector cared, it will indeed work just the same as fiberglass but would be more fire resistant, reduced toxic fumes, etc. It is not wallet-friendly though!
guy.. where I live rockwool is cheaper than fibreglass. …you know what else is cheaper and falls under “good enough” for the vast majority of us, including most home studios..? using it in a regular wall cavity instead of spending twice as much $ on lumbar and insulation (of any type) to build a double wall/doubly insulated with an air gap in-between… .. I mean sure, if you have the available space and budget to do the double wall thing then go for it – but thats really only necessary for a wall between the studio mixing room and an isolation booth… also.. seriously, don’t try to spin a double wall as more affordable option than rockwool for the masses in standard wall construction. which still works very well all things considered…lol…
Rockwool Safe’n’Sound and Comfortbatt are the same material. The Comfortbatt is 3.5 inches thick which fills the entire stud cavity depth and thus provides better thermal insulation. The Safe’n’Sound is not as thick, at only 3 inches, which provides a built-in air gap in your wall and is why it’s rated only for sound and not thermal. Fiberglass usually comes in 3.5 inch thickness and would not have an air gap. If you’re building only one wall, then Safe’n’Sound with the gap should perform better than fiberglass with no gap because of the air spring that you mentioned. But if you’re building a double wall then you’re actually paying more money for less insulation if you choose Rockwool Safe’n’Sound over fiberglass.
🎯 Key Takeaways for quick navigation: 00:00 🎤 Soundproofing is not just about insulation; it’s about the entire wall assembly, including factors like decoupling, mass, and air gaps. 02:20 🏠 Rockwool Safe and Sound is not suitable for exterior walls as it lacks an R-value for proper insulation. 03:56 💰 Rockwool Safe and Sound is more expensive than alternative insulation materials like fiberglass, which offer similar acoustic performance. 06:44 💲 Choosing a cheaper insulation option like Owens Corning’s Craft R13 can save you a significant amount of money without compromising soundproofing quality. 09:00 🛠️ Rockwool is excellent for acoustic treatment and panels but not the best choice for soundproofing walls in a recording studio or soundproof room. Made with HARPA AI
Hard disagree. Rockwool is far more efficient than others whether or not used in an ‘assembly’. And iut’s the only insulation I would ever use. Although it is true that when combined with mass loaded vinyl, foam, and a de-cuppled system using whisper clips dampening (not soundproofing) is going to be much better. Personal experience beats all not just ‘research’. I’d be interested to know if you’ve actually built a sound dampened room? Because most bros yapping on YouTube can’t backup what they’re going on about. They simply think research is enough and call it a day. What I’m saying is they put out content without having the personal experience, so which are you?
At 8:31 you just contradicted your entire article and made the case for rock wool sound proof. Think about it for a minute and you will see why. (One minute later) if rockwool can reduce acoustic reflections then it reduces the overall deadness of your studio, even if it is in a wall and not on the surface. Going through drywall doesn’t magically nullify the effect of the rock wall in the wall. sound waves penetrate all surfaces to some degree, internal surfaces reflect, if it hits rockwool and it has a higher absorption than fiberglass then physically it reflects less. Agreed, not as effective as just hanging on a bare wall, but it still is doing the physics you mention. The comments of real world experiences in this article testify to the value of reflection diminishment. Moreover you neglected to mention that sound proof as a definition depends on the context or use case. Are you trying to prevent reflection or transmission, or both?
I read so many of the comments and so many people are missing the point of this article. My key takeaway is that Rockwool is no more effective than pink insulation in a decoupled double wall construction designed for soundproofing. So don’t waste your money on it when soundproofing using the double wall design.
The problem I have with Youtubers saying not to use mineral wool soundproofing insulation is that while you insist there’s no difference I have experienced the real world difference when it comes to NOT spending $60,000 on building a room inside a room and double drywalling both sides. R13 provides near zero sound difference to not at all and the proper safe and sound difference is stark. And yes I know you are going to say, “in a lab they found this so your wrong and blah blah blah. I’m talking real world and I don’t live in a lab I live in the real world and I’ve installed the stuff. it’s not the same by any stretch.
This is an example of why to be careful of influencers that rely on likes. Rockwool Comfortbatt has Rvalue and acoustic insulation also same material different brand is Thermofiber fire and sound guard. Fiberglass is a horrible insulation product. Fiberglass is only rated for 15-20 years and falls apart and loses insulation value, holds moisture and produces mold when wet and is flamible.
Video summary (00:00:00)(^1^) – (00:09:58)(^2^): This article explains why rockwool safe and sound is not a good choice for soundproofing walls. It covers the physics of soundproofing, the difference between soundproofing and acoustic treatment, the importance of R value for insulation, and the cost comparison of rockwool and fiberglass. **Highlights**: + (00:00:00)(^3^) *The misconception of rockwool for soundproofing* * Many people think rockwool is essential for soundproofing * The article challenges this idea and shows why it’s not true + (00:01:21)(^4^) *The physics of soundproofing* * Soundproofing is about the system as a whole, not just the insulation * A mass-spring-mass system is the best way to isolate sound * The type of insulation does not make a big difference + (00:03:21)(^5^) *The difference between soundproofing and acoustic treatment* * Rockwool is good for acoustic panels and reducing reflections in the room * It is not very effective for soundproofing and isolating sound * Soundproofing requires a proper wall design and decoupling + (00:05:01)(^6^) *The importance of R value for insulation* * Rockwool safe and sound does not have an R value and is not meant for exterior walls * R value is important for climate control and energy efficiency * Different walls and regions require different R values + (00:06:36)(^7^) *The cost comparison of rockwool and fiberglass* * Rockwool safe and sound is more expensive than fiberglass insulation * The article shows an example of how much money can be saved by choosing fiberglass * The article recommends cutting corners on insulation and not on soundproofing
disagree strongly with the premise of this article. Using quality materials simply works. The failure is only using rockwool. If your wall is composed mainly of 3 materials then all 3 materials need to be of quality. Now lets upgrade our 2x4s to metal studs. We can use 6″ steel studs now we have upgraded 2 of our 3 materials and our stc rating has skyrocketed all the way to 52! with the use of 16″ spacing and 5.5″ rockwool. Yes we have already achieved over 50stc without exotic materials or complicated assembly… just plain old quality materials Now lets upgrade our 3rd material, the drywall, from a standard 5/8ths gypsum to soundbreak XP. Now we have an stc rating over 60!!! Notice we didnt need to build a room within a room… we didnt touch mlv. We didnt have to apply green glue (although something is recommended around outlets and such) No complicated wall assembly. No staggered studs. No double dry wall. no resilient websites. no overly wide spacing between studs. No complications at all really all we did was use quality sound rated materials Some people may not have liked the use of 6″ studs in my prior example. So lets take a step back and go to 3.5″ metal studs 3-5/8″ steel studs, 20 gauge (19 mil), 16″ o.c. Insulation: 3-1/2″ glass fiber side 1: 5/8″ SoundBreak XP Wall Board side 2: 5/8″ SoundBreak XP Wall Board This is a VERY basic wall assembly, and we get 50stc just by using quality materials… and thats with glass fiber . when you implement the safe n sound once again stc skyrockets do you see the importance of simply using quality materials?
Let’s compare *Rockwool insulation**, **Rockwool Safe’n’Sound**, and **fiberglass insulation* in terms of their **R-values**: 1. **Rockwool Insulation**: – **R-Value**: Rockwool insulation has an R-value ranging from **3.0 to 3.3 per inch**. – **Composition**: Rockwool (also known as Roxul) is made from rocks and absorbs sound waves effectively. It is fire-resistant, durable, water-repellent, and resistant to mold buildup. – **Applications**: Rockwool can be used in walls, ceilings, floors, attics, engine compartments, and machinery rooms. – **Soundproofing**: Due to its density and porosity, Rockwool is a great temperature and sound insulator. 2. **Rockwool Safe’n’Sound**: – *R-Value**: Rockwool Safe’n’Sound has a density of **2.5 lb/ft³* and does not specify a R-value, since insulation is not its primary purpose: – **STC (Sound Transmission Class)**: 45 on 16″ for center wood studs, 52 with 24″ for center steel studs, and 50 when installed between floor joists. – **Noise Reduction Coefficient (NRC)**: 1.05 for 3-inch thickness, which is better for sound control. – **Composition**: Similar to Rockwool, it is made of mineral wool and offers sound absorption and vibration reduction. – **Applications**: Suitable for walls, ceilings, floors, and attics. – **Effectiveness**: Effective for soundproofing. 3. **Fiberglass Insulation**: – **R-Value**: Fiberglass insulation has an R-value ranging from **2.2 to 2.7 per inch**. – **Composition**: Made of glass fibers, it is commonly used for thermal insulation.
You’re actually a little incorrect. Just because you haven’t found the R value of “Safe and Sound” does not mean it has NONE! As a contractor, I had to know the difference, so I actually SPOKE with their tech department about 6 years ago. Because one of these products is “slightly” thicker, it is a better choice for thermal insulation, while the other is 1/2″ less thick, but better for sound resistance. This does cause it to have a “SLIGHTLY” less R-Value, but, it’s the better choice for “sound proofing”. Because othe OTHER, “Comfort Batt”, is better for temperature contnrol, they post its R Value of 15! The teck explained to me that; the “Comfort Batt” is is a full 3 1/2″ thick completely filling a 2×4 wall cavity, and that 1/2″, gives it a slightly BETTER R-value. Whereas, the “Safe-N-Sound” is only 3″ thick. This is to provide a small 1/2″ air gap in that same 2×4 wall cavity. By not permitting the rockwool to touch BOTH opposing wall surfaces, any potential sound transfer would ONLY be through the studs, and NOT the rockwool insulation itself, unlike any that might occur with the Commfort Batt. He said the ONLY real tradeoff is 1/2″ material, and that if you live on a noisy street EITHER would be acceptable, but the customer would need to decide which benefit they prefer! I have NO idea why they don’t just list the R value of each, but I think he said it’s about R-12 or 13 for the.
I’d love to know: Where did you search up Rockwool Safe n Sound at Home Depot for $56!!! If this article came out 2 months ago on this date here in the North East RockWool Safe n Sound is $82!!! even more so a roll of R13 Batts are also $82! .71 cents a sqft vs $1.38 a sqft. Safe n Sound is pretty much double the cost, but if it was $56 like you show I’d buy it in a heart beat!!!
Installed a wall between a bedroom and a living room. Use 2 x 6 wooden studs, 5″ Roxul mineral wool (6 lb/cf density) and fire code (type X) drywall 5/8″ thick on both sides. The fire code drywall has a lower cellulose content and higher cementitious content than normal drywall and is less prone to support mold growth. And a solid core door with a door seal at the bottom edge. Very quiet in the bedroom. It does not occupy as much space as a double wall. I would always recommend high density mineral wool over fiberglass due to higher mass and it is fireproof. Mineral wool is used in your oven for insulation. For a studio, yes, STC 63 is terrific. I would still use higher density mineral wool and thicker drywall for improved performance. Yes, your material cost may be higher, but the labor and other material costs are the same. Small price to pay for the potential improvement. Its a better wall in many ways. Use a split system for heat and AC in the studio and control room. Windows? Doors? They must meet the same STC value as the walls. Actually use the OITC rating for doors and windows rather than STC if they go to the outdoors. You may need a vestibule for the door entrance; 2 doors with a sound absorptive corridor between them to achieve STC 63 equivalence. Magnetic seals around the metal doors. Forget the windows. No windows to the outside.
Please give me some guidance. I have 2 21″ horn loaded subwoofers in my basement. I mix music at very loud volumes, so I can feel the music. The issue I am having is my neighbor 70yds away will no longer tolerate the bass sounds he is getting in his house. What can I do to help mitigate or absorb these waves or redirect. I have been doing some research and I believe that properly making some sort of panel designs and bass traps. Also, while setting up my subwoofers in a cardioid placement, I am hoping to help with the situation. What are your thoughts?
To me it seems the best value without losing space is a what is called a staggered stud wall. For example, if a 2×4 wall, use 2×3 studs alternating 16″ OC on both sides of the wall. Itll decouple the studs as well provide a nailing face for 5/8 drywall as well as provide a space for insulation (take your pick)
Hey man, thanks for the great article! I live in a flat where neighbours complained of noise few times, and I have an acoustic-sized electronic drumkit, meaning with normal sized, hollow drum shells. I did audio tests pre-and-post filling the entire kick drum with 2 huge blankets & a heavy bike lock, and I got about a 3dB reduction in noise. I got noise complaints again and was thinking of filling the kick drum, as well as other toms, again, but with better materials. I thought of Rockrool immediatelly as I had heard a lot about it, but unsure it would help after seeing your article. Any idea/alternative suggestions? Thank you 🙂
What if I need to soundproof the ceiling between the basement and the main floor living area? Is installing Rockwool insulation behind the ceiling tiles (which are already removed due to water damage) recommended? Just trying to find solutions to recording studio noise in basement, while ceiling tiles down are already down. I don’t have a whole lot of money to invest. Thoughts? Btw, I sound a deal on some Rockwool, for about .50 per sq ft
Hello, i just happened to come across this article after researching rockwool insulation. I work online and i need to soundproof my home. The walls are concrete, the floor is tiled with louvers glass windows. I need some advice as to what materials i should use, please. I would really really appreciate your help please. Thank you.
Hey man, love your articles. Im glad I found your website before I start my studio build… I am building a recording studio in my basement. as it sits now the 2×4 framing is up against the house, so concrete floor, and concrete walls surrounding. would you recommend building a double wall in this scenario, or could I get away with decoupling and using 2 sheets of drywall on a single wall system?
Question about wall assembly and decoupling. Presuming a “single leaf budget” – I would be working with single leaf exterior walls made of wood. I understand that studs 24″ OC will deliver slightly better results than studs 16″ OC primarily because of reduced coupling (less connections from interior to exterior). Now, to extrapolate that to a pole barn or post frame construction, if the “studs” were actually 6×6 posts spaced 8 feet apart, should this further decoupling result in a better single leaf wall?
I have a Duplex I renovated and tried several methods of soundproofing the party wall between the two suites. one day I went in, ripped out the drywall on one side, I then had 2 back to back 2×4 walls with an air gap like in his diagram, my tenant was on the other side with only 1 layer of drywall seperating us. When he talked it was like he was in the same room as me, almost no soundproofing. That night I filled both wall cavities with safe and sound, being careful to fit each batt perfectly and maintain my air gap between the walls . The next day I came in to board the wall on my side. I was completely shocked when my tenant talked on his side, the safe and sound had made practically zero difference, it sounded almost the exact same. Once the first layer was boarded on my side it almost completely drowned him out. my take away from that was that insulation is not a game changer, what seemed to be a game changer for me was doing multiple layers of drywall with green glue in between (an acoustical air gap layer) I ended up doing 2 layers of 5/8 drywall and I couldn’t hear talking at all. A few years later I renovated the other side and did 2 layers of 1/2″ then 1 layer of 5/8 drywall with greenglue. That wall is super soundproof. A blender on full is barely audible. If I were to soundproof any walls going forward I think I would do 3 layers of drywall with greenglue. 3 layers of 1/2″ just keep price down a bit. this should give you a fire rating too, but just to be safe you could finish the last layer with 5/8 type X so no inspector could argue otherwise.