Sheathing Option: Save Money, Meet Fire Code

LP Fire-Rated OSB Sheathing is engineered for fire code compliance and design flexibility.

Designing to meet code requirements is not always an easy process- but building codes, and particularly those addressing fire, are designed to protect the lives of building occupants and first responders and therefore will continue to be a key component to the design and construction of buildings.
Fortunately, there are often multiple ways to meet code requirement with fire-rated wall assemblies and LP FlameBlock Fire-Rated OSB Sheathing offers architects and designers an opportunity to meet code requirements while saving money and time compared to alternative assembly options.

Featuring an ignition-resistant Pyrotite coating, LP FlameBlockOSB is a listed component in fire-rated interior wall assemblies, exterior wall assemblies, and roof deck applications. The fire-rated structural sheathing provides 15-minute thermal barrier protection, a 30-minute Class A flame spread rating, and a combination of flame spread resistance and burn-through resistance. What’s more, it provides additional value in the form of strength, savings, and greater design flexibility and is versatile enough for use in Type II, III, and V construction.

Because structural design values for LP FlameBlock sheathing are not reduced by the fire-retardant treatment, the panel carries load/span and shear design values equivalent to an untreated wood structural panel in the same panel thickness category. Using LP FlameBlock sheathing in fire-rated wall assemblies can provide more flexibility in design of wall openings as well as more options in framing and bracing to meet structural requirements. Finally, each panel carries an Exposure 1 classification, meaning it can withstand exposure to moisture during normal construction delays.


  • ICC-certified (ESR-1365)
  • 15-minute thermal barrier protection (UBC 26-2)
  • 30-minute Class A Flame Spread Rating (ASTM E84, UL723)
  • Combination of flame-spread resistance and burn-through resistance
  • Code-compliant component of fire-rated interior and exterior wall assemblies and roof decks

Read the full technical guide.