Introducing Johns Manville CladStone™ Water & Fire Block Insulation

Johns Manville (JM), a Berkshire Hathaway company and leading building products manufacturer, announced the launch of JM CladStone™ Water & Fire Block Insulation, a noncombustible continuous insulation mineral wool product. This premium mineral wool product allows for the effective drainage of water from an exterior wall cavity system, while offering exceptional thermal efficiency, fire resistance and acoustical performance. The addition of this new product further enhances the breadth and depth of JM’s complete line of insulation products by providing the market with a rain screen product that works with a variety of exterior cladding systems.

JM CladStone Water & Fire Block is specifically manufactured for superior performance in cavity wall and rain screen applications. Made from basalt, a volcanic rock, JM CladStone Water & Fire Block is naturally noncombustible, moisture repellent, non-deteriorating, and will not mildew or support corrosion.

Additional product performance advantages include:

  • Use with a wide variety of cladding systems: JM CladStone can be installed with a variety of exterior cladding systems including strapping, brick ties, girts and purlins, and other exterior cladding mechanical attachment systems
  • Flexible installation: JM CladStone can be mechanically fastened using impaling pins, screws and washers, insulation fasteners, plastic cap nails, or other fasteners
  • Smart engineering: Advanced manufacturing technology ensures consistent product quality, with high-fiber density and low shot content for excellent performance

“We are committed to providing our customers with an array of products to meet the needs of any project, and that’s why we’re introducing JM CladStone Water & Fire Block Insulation, a noncombustible product designed to aid in managing moisture in continuous insulation systems,” said Tommy Knappich, Vice President and General Manager of Building Insulation at Johns Manville. “We aim to provide the highest level of service to customers and constantly look for opportunities to enhance the versatility of our high-performance insulation product line to meet the needs of today’s increasingly demanding project requirements.”

JM CladStone™ Water & Fire Block is available to customers in the United States and Canada immediately. To learn more, visit or talk to a JM Building Insulation representative.

About Johns Manville

Johns Manville, a Berkshire Hathaway company (NYSE: BRK.A, BRK.B), is a leading manufacturer and marketer of premium-quality products for building insulation, mechanical insulation, commercial roofing, and roof insulation, as well as fibers and nonwovens for commercial, industrial and residential applications. JM serves markets that include aerospace, automotive and transportation, air handling, appliance, HVAC, pipe and equipment, filtration, waterproofing, building, flooring, interiors and wind energy. In business since 1858, the Denver-based company has annual sales of approximately $3 billion and holds leadership positions in all of the key markets that it serves. JM employs approximately 7,000 people and operates 43 manufacturing facilities in North America, Europe and China. Additional information can be found at

Linhart PR for Johns Manville Kelly Nash, 303-515-2404