Is Exterior Sheating Considered Fire Rated?

LP FlameBlock sheathing is a fire-resistant material used in both wood and steel framing to provide fire resistance and weather protection when used under exterior claddings such as wood, vinyl, fiber cement siding, and masonry veneer. It is a component of 1- and 2-hour fire-rated wall assemblies and roof deck applications, combining flame-spread and burn-through resistance.

Exterior Gypsum Sheathing is a specialized performance panel consisting of a noncombustible, moisture-resistant core wrapped in glass mat facers on both the front and back surfaces and long edges. It has greater fire resistance and mold and moisture resistance than wood sheathing alternatives. The high-performance, poured polyurethane insulation layer fused to the sheathing provides an easy way to comply with continuous insulation requirements in building codes.

There is no fire-rated wood sheathing, only fire retardant. Exterior walls are non-combustible under Type IIIA construction, but FRTW is allowed in Type IIIA exterior walls. 5/8″ Exterior Gypsum Sheathing has a Type X core for use in fire-rated assemblies. Gypsum wallboard manufactured by American Gypsum contains no asbestos.

Plywood is not fire-rated but fire-retardent treated (FRT) and is considered “limited combustible”. Structural Insulated Sheathing (SIS) has undergone rigorous ICC testing, receiving a two-hour fire-resistant rating. For exterior gypsum, Densglass Gold is used as a backer for siding in wildland areas that require fire rating.

In summary, LP FlameBlock sheathing is a fire-resistant material used in both wood and steel framing to protect the building’s structure and prevent fire spread.

Is OSB plywood fire rated?

Fire-rated OSB and Fire Retardant Treated (FRT) plywood are commonly used in fire-rated wall sheathing and roof deck applications. OSB, like LP FlameBlock, combines an ignition-resistant, cementitious coating with OSB, allowing it to withstand normal moisture exposure during construction. FRT, on the other hand, is applied after the plywood is manufactured and may be water-soluble, requiring protection from moisture during construction.

OSB products like LP FlameBlock offer flame-spread and burn-through resistance in the same panel, as verified in tests like the 30-minute Class A Flame Spread Rating and 15-minute Thermal Barrier Protection test. FRT plywood has a flame spread rating but no burn-through resistance rating.

Is OSB sheathing fire rated?

LP FlameBlock Fire-Rated OSB Sheathing has been certified by the International Code Council (ICC), offering additional value, strength, savings, and design flexibility. This enables the construction of fire-rated wall assemblies and roof decks to be completed more rapidly and at a lower cost.

What is the fire rating of DensGlass sheathing?

DensGlass® Sheathing is a high-performance fiberglass mat gypsum sheathing board with over 30 years of use worldwide. It is the first specified product by architects in the US for its superior mold and moisture resistance compared to paper-faced sheathings. DensGlass® Sheathing is strong, moisture-resistant, and has an A1 non-combustible reaction to fire classification, making it the Gold standard. When tested in accordance with ASTM D3273, it scored a 10, the highest level of performance for mold resistance.

What is the difference between a fire wall and an exterior wall?

Firewalls are sturdy walls designed to withstand fire for up to four hours, ensuring the building remains standing even if other parts collapse. These thicker walls stretch from the foundation to the roof, and are considered separate buildings if they are subdivided. They must meet ASTM fire-resistance building standards and can be supported with pilasters or buttresses. Standard firewalls are made from concrete or masonry and lack windows, doors, or other openings. Expansion joints allow the material to expand to withstand fire heat. Firewalls also need to withstand force from other collapsed structures or items within the building.

Do external walls need to be fire rated?

In order to comply with the requirements set forth in Section 3 (Means of Escape), Section 6 (Load-bearing Elements of Structures), or Section 11 (Resisting Fire Spread from One Building to Another), an external wall may be required to demonstrate fire resistance.

Is an exterior wall a fire rated wall?

The fire resistance rating for exterior walls is determined by construction type, occupancy, and fire separation distance, as defined in Section 6 of the IBC. The rating ranges from no required rating to 3 hours. However, walls 10 feet or less from the property line must have a fire resistance rating based on proximity to adjacent buildings and interior occupancy conditions. The 2009 IBC increased this distance from five to 10 feet. Openings in exterior walls typically consist of windows and doors, and codes distinguish between “protected” (fire-rated doors, windows, shutters) and “unprotected” (no fire rating).

Can OSB be used as fire barrier?

LP Building Products’ LP FlameBlock® Fire-Rated OSB Sheathing represents a unique product that combines structural performance with fire resistance. This is achieved through the use of a proprietary non-combustible, fiberglass-reinforced Pyrotite® layer.

Is exterior sheathing fire rated?

Exterior Gypsum Sheathing is a type of building material used for providing fire resistance and structural strength under exterior finishes like wood, metal, or vinyl siding. It is designed for direct attachment to wood framing using galvanized nails or staples and screws, or metal framing using screws. However, it is not intended for finishing with drywall joint compound and tape. Special lengths may be available on special order. When properly transported, stored, handled, installed, and maintained, exterior Gypsum Sheathing does not generate or support mold growth.

Is exterior grade plywood fire rated?

Chicago Flameproof offers a full line of exterior grade fire retardant treated plywood, which is a great choice for building projects. This type of plywood is treated with fire retardant preservatives, allowing it to burn slower in case of a building fire, preventing extra damage to the building and its interior. The company is FSC Certified and offers shipping anywhere in the United States. If you have any questions about the company or their products, you can contact them at 866. 884. 7594. Chicago Flameproof is located in four states and can be reached at 866. 884. 7594.

How do I know if my sheathing is fire rated?

It is imperative that all fire-rated plywood be accompanied by a stamp, as unlabeled wood is not guaranteed to meet the requisite standards for fire resistance as set forth by the industry. It is possible that damage or cutting may obscure the stamp, and wood that is labeled but lacks a stamp may not meet the requisite standards.

What plywood doesn’t catch on fire?

Fireproof plywood, or fire retardant plywood, is engineered wood treated with specific chemicals to slow down fire spread. It offers superior resistance compared to regular plywood, allowing for more efficient evacuation and fire control. It acts as a barrier, delaying flame spread and enabling safe evacuation in case of a fire, making it a popular choice for projects requiring fire safety.