Quantum Performance Building Products installs a lot of Roxul in Maine homes. This product is produced from steel slag and is fibrous just like the traditional fiberglass batts. It allows less air movement through the material so it does a better job of insulating than traditional fiberglass insulation. It is important to remember that roxul allows a large amount of air movement. Air is the largest transport of both heat and moisture so its not the greatest insulation on the market but it does provide some benefits.

Benefits include

  • Good STC rating for sound control
  • Will not burn due to it being made from non combustible materials
  • Will provide decent insulation value when combined with a rigid insulation on the exterior.
  • Comparable price to Bib System Insulation


  • Does not stop air flow
  • Allows warm air to pass through and create condensation on roofdeck or wall
  • Falls apart when fitting around lights, plumbing, and mechanicals
  • Is a natural irritant

Even though moisture moves through the material via air it is still possible to make a good system with the combined use of blue board and smart air barriers on the interior.