When exposed to water all roof boards lose strength, including flexural strength, but to varying degrees. In third-party test results of 1/2″ roof boards:
*Third-party testing of 1/2” boards conducted by Trinity ERD in Columbia, South Carolina in October 2016 and December 2017. Testing conducted in accordance to ASTM C473 to meet ASTM C1177.
In third-party test results comparing ½” DensDeck® Prime Roof Board to other roof board materials:
*Testing of ½” boards conducted by PRI Construction Materials Technologies in October 2017 and in accordance to ASTM C209
To varying degrees, exposure to freeze/thaw cycles have a compromising effect on the vertical pull strength of all roof boards, producing cracks and ruptures that continue to grow with time and lead to delamination. In vertical pull strength testing of 1/2″ roof board materials after exposure to 21 freeze/thaw cycles:
*Third-party testing conducted by PRI Construction Materials Technologies LLC in Tampa, FL, concluding in May 2018. Test conducted in accordance to a modified form of ASTM C67 as well as ASTM C209.
In third-party test results comparing ½” DensDeck® Prime Roof Board to other roof board materials:
*Testing conducted by PRI Construction Materials Technologies in October 2017 and in accordance to ASTM C473. ½” boards tested for DensDeck® Prime Roof Boards, gypsum fiber and alternative coated glass-mat gypsum roof boards.
In third-party test results of ½” DensDeck® Prime Roof Board versus other materials:
NOTE: Moisture has a detrimental effect on every cover board, including DensDeck® Roof Boards and every effort should be taken to keep them dry before, during and after installation. Damage or reduction in performance resulting from exposure to more than an incidental amount of moisture is NOT covered by the limited warranty for DensDeck® Roof Boards. For additional information on installation guidelines and product warranty, please see Resources.
*Testing conducted by PRI Construction Materials Technologies in October 2017 and in accordance to ASTM C473. ½” boards tested for DensDeck® Prime Roof Boards, gypsum fiber and alternative coated glass-mat gypsum roof boards.
Enhancing the durability and puncture resistance of the DensDeck® Roof Board offerings for FM Global Very Severe Hail (VSH) rating specifications, DensDeck® StormX™ Prime Roof Board meets these rigid standards for impact resistance, using engineering ingenuity to help reduce roof assembly storm damage risk.
FM Global tests roof systems for moderate and severe hail impact resistance on how the withstand dropping a 2-inch diameter 1.19-pound steel ball from either 81 inches or 141.5 inches, respectively. This results in impact energies of 8 ft-lbs for moderate hail (1.75″ or bigger) and 14 ft-lbs for severe hail (2″ or bigger). The new VSH designation uses an ice launcher to propel a 2-inch diameter laboratory-made ice ball at 152 to 160 feet per second. This applies impact energy of 53 to 58 foot-pounds on the surface of the tested sample–an increase of almost 4x compared to severe hail. Learn more about FM’s VSH impact-resistance classification here.