Fire Rated Party Wall

Greenfiber FRM Party Wall

Greenfiber Sanctuary Two-Hour Firewall logo.

Looking for unparalleled fire resistance combined with sound control and reduced air infiltration? Here is your answer: Greenfiber FRM Party Wall. When used in combination with our proprietary U370 firewall design, the SANCTUARY Two-Hour Firewall achieves a Two-Hour Fire Resistance Rating.* Ideal for townhome and multifamily construction. In addition, the combination offers exceptional sound attenuation and reduced air infiltration, all while boasting the only carbon negative footprint from a firewall in the industry. The U370 firewall design uses Greenfiber FRM100 insulation for a defect-free installation. FRM 100 is spray applied in an 8” cavity between two opposing and offset studded walls. This product delivers unparalleled fire resistance, achieving a Two-Hour Fire Resistance Rating*; exceptional thermal performance of R-30; and superior sound control of STC 56 or greater. This product is rated by Underwriters Laboratory.

  • Premium, professional-grade insulation with proprietary U370 firewall construction is ideal for any environment where exceptional fire resistance, sound control and thermal performance is desired—townhomes, multifamily construction, etc.
  • With an R-value per inch up to 3.8, fire rated party wall achieves an R-30 in an 8” wall.
  • FRM contributes to an efficient construction cycle, resulting in significant time and money savings
Isolated Greenfiber Fire Rated Material package.

Click to view the Greenfiber FRM Sales sheet.(opens in a new tab/window)

Click to view the Greenfiber FRM Product Brochure.(opens in a new tab/window)

Click to view the Greenfiber FRM Safety Data Sheet.(opens in a new tab/window)


Originally rated by Underwriters Laboratory in 2002, the SANCTUARY® Two-Hour Firewall uses Greenfiber® FRM spray-applied cellulose insulation for a defect-free installation, currently available in select markets.

Streamlined Installation

Because Greenfiber FRM insulation is blown in after the roof goes up, conventional framing is possible. That means, in addition to being protected from the elements, the SANCTUARY Two-Hour Firewall allows all trades to work simultaneously, which normalizes the sequence of construction.

Improved Compliance

To meet stringent energy efficiency codes, the SANCTUARY Two-Hour Firewall utilizes spray-applied Greenfiber FRM Insulation that completely fills gaps, voids and hard-to-reach places, reducing unintended airflow. This lowers the air changes per hour, eliminating customer callbacks.

Enhanced Comfort for Homeowners

Because the SANCTUARY Two-Hour Firewall fills gaps so completely, sounds and odors are blocked between neighboring units. Homeowners have much more control over their own indoor air quality, which allows them to live more comfortably.

Mid Atlantic Party Wall

We are proud to partner with Mid-Atlantic Party Wall, serving customers throughout the region with expert installation and service.

*Evaluation Services Report 2016