Fiberboard Roofing Substrate

Completes a project reliably and economically

Durable and dependable, fiberboard roofing substrate helps you stay on top of any roofing application. As basic as a standard built-up roof, yet as current as today's single-ply systems, fiberboard is durable and consistent, easy to handle, easy to apply, and lasts for years in both re-rof and new applications.




Roof fiberboard's interlocking, high-density wood fibers make installations strong and rigid.


Count on fiberboard to stand up during:

  • Normal storage
  • Construction handling
  • Roof traffic


Easy to handle and fast to apply, roof fiberboard:

  • Creates a smooth, even substrate
  • Provides uniform density
  • Offers accurate dimensions


 Roof fiberboard provides choices of:

  • Thickness
  • Length/width
  • Surface finishes for modified bitumen, BUR, EPDM, and PVC membranes
  • Factory-applied surface coating to reduce asphalt or adhesive "strike-in" when adhered roofing systems are required






Roof fiberboard manufacturers have obtained approvals from a  variety of code and regulatory organizations. Check your supplier approvals.


Do not apply flame directly to roof fiberboard. Roof fiberboard may smolder or burn. Extinguish completely if ignited. For specific recommendations, refer to the manufacturer's application instructions.

Physical Properties * Table 1

Recommended Roof Covering
Grade 1
BUR Ballasted Systems
Grade 2
Totally Adhered Membranes
Transverse Strength (min.) PSI 7 12
Tensile Strength Parallel to Surface PSI 50 150
Tensile Strength Perpendicular to Surface PSI 500 600
Water Absorption Percent 10 7
*ASTM C208