FlameBlock
LP® FlameBlock® Fire-Rated OSB Sheathing offers you the best of both worlds—impressive structural strength and remarkable burn-through fire resistance. Created by applying a patented, non-combustible Pyrotite® coating to LP® OSB panels, LP FlameBlock Sheathing is an ICC certified (ESR-1365), structural fire-rated sheathing with a Class A Flame Spread Rating. It provides extended burn-through resistance, delivering a 20-minute thermal barrier (ASTM E119). It’s durable on the job site, easy to work with, and is Exposure-1 rated to withstand weather during normal construction delays. LP FlameBlock Sheathing is cost competitive and is available in a variety of PS2-rated thicknesses and lengths, including Struc-1. Plus it contains no hazardous chemicals. Backed by a 20-Year Transferable Limited Warranty, LP FlameBlock Sheathing is the one to count on when every minute counts.
Product Tabs
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- Structural Fire-Rated Sheathing
- Class A Flame Spread Rating
- 3 Times Longer Burn-Through Resistance Than Standard Wood Sheathing
- Non-Combustible, Fiberglass-Reinforced Magnesium Oxide Coating Over LP® OSB
- Two Quarts Of Water Locked Into Each 32 Square Feet Of Coating (4' x 8')
- Allows For Faster, More Cost-Effective Compliance With Fire Codes, Even In Seismic Zones
- Durable, Easy To Handle On Job Site
- No Hazardous Chemicals
- Variety Of PS2-Rated Thicknesses And Lengths, Including Struc-1
- 20-Year Transferable Limited Warranty
*Performance category replaces the fractional nominal thickness used in PS2. The Performance Category is consistent with the panel thickness used in the U.S. model building codes.

