I've been reading a lot of info from Europe on rock wool. It is claimed to be close in R-value to foam and much greener with open vapor. I am interested in using for exterior and basement insulation. Does anyone have experience using rigid rock wool? Thanks.

Views: 476

Reply to This

Replies to This Discussion

Hi Richard,
I'm not sure about your reference to "Ridgid" rock wool. I'm somewhat familiar with Roxul which is a high density cavity insulation and I like it. As for basements, there are SO MANY other considerations, but yes, for a layer inside of some rigid foam panels it looks good.


Rock wool is available in rigid product, with various densities, depending on application.

There is a product designed as drain board for foundations.

It's available in pipe insulation, batts, and blown in. Although you may have a hard time finding or getting.

Look for industrial / commercial / wholesale insulation suppliers.

It's fireproof & waterproof, lower embodied energy than foam, but has formaldahyde glues still.

I have used a few brands of rigid batts for air sealing and found the Roxul brand better. Roxul is more dense and easier to cut  and we use it frequently for air sealing in areas where foam will not work and some chase areas. Most brands are marketed as acoustical batting,  however I have seen Roxul reps at the big box stores promoting the product for general attic/wall insulation against fiberglass. For attics cellulose is more cost effective and any rigid  batt (rock wool or fiberglass) used in attic insulation  is problematic. Rock wool has great thermal characteristics and does not wick water making it a good choice for basements and exterior applications. My only complaint is rock wool (slag) fibers are nasty.

Thanks Jose

For exterior application do you attach directly or with drainage plane?

I have not used Roxul for exterior applications- only airsealing and basements. Check their website as I believe Roxul offers additional products specifically for exterior applications



  • Add Videos
  • View All


Latest Activity

Seth Romme is now a member of Home Energy Pros
4 hours ago
John Nicholas replied to Rob Madden's discussion Blower Door Testing on Energy Star v3 home
"So you have a slab on grade home, duct work in the attic?"
17 hours ago
Diane Jackson posted a photo

"Drive Home"

Addison Homes spent a fun day with a film crew from the National Association of Home Builders. We…
Paul Raymer posted a blog post

Healthy Home Evaluator Training

Fall River, MA     October 13, 2016…See More
Diane Chojnowski updated an event

Better homes video series at Seventhwave

October 24, 2016 to January 26, 2017
Profile Iconseoeleczo and Parfait Pouliotte joined Home Energy Pros
Amber Vignieri's blog post was featured
Sarah Holloway's blog post was featured

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service