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What is Fire-Rated Gypsum Board?


Fire-rated gypsum board is a form of drywall that helps prevent the spread of flames across a home or business. Gypsum is approximately 21% chemically combined water, which greatly contributes to its effectiveness as a fire-resistive barrier. When gypsum drywall is exposed to fire, the water is slowly released as steam, effectively slowing heat transmission. This gypsum is used to develop fire-resistant drywall.

Fire-rated gypsum drywall is more fire-resistant because it contains glass fiber reinforcement and other additives within its specially formulated gypsum core to help it hold up longer to fire exposure. 

Fire rated drywall is referred to as “Type X” and must be third-party certified by an independent testing and listing agency such as UL (Underwriters Laboratories Inc.) and ULC (Underwriters’ Laboratories of Canada) to meet the fire performance requirements prescribed in the ASTM C1396 Standard Specification for Gypsum Board.

Not only does this drywall reduce the spread of flames, saving countless lives each year, but it has become a requirement in the building codes for dry, fire-prone regions in order to limit the amount of damage caused by seasonal fires. 

The Insurance Institute for Business & Home Safety (IBHS), in partnership with Headwaters Economics, reported that more than 35,000 structures were lost to wildfires in the last decade. By mandating fire-resistant drywall in building codes, this number will start to drop. Fortunately, the cost of installing this drywall for homebuilders is minimal. The IBHS reports that wildfire-resistant construction actually costs two percent less than typical construction materials. This means you can protect future homes from fire damage while saving money.  

At CertainTeed, we strive to create fire-rated drywall that meets the strictest code standards while looking ahead to develop even better products in the future. There are a few key factors to keep in mind as you shop for fire-rated gypsum board. The first is the Flame Spread Rating. The National Fire Protection Association (NFPA) Life Safety Code has five classes of flame spread, which rates materials on a scale of 0-500+. This rating measures the rate at which a flame will spread over a material. Red oak has a rating of 100 and anything considered Class A fire-resistant needs a rating of 0-25. 

Fire-resistant drywall has a flame spread rating of 15, well below the maximum spread for a Class A product. Some CertainTeed products have a flame spread rating of zero. Additionally, most of our products have a Smoke Developed rating of zero, per ASTM E84, which means our products do not create smoke when they burn, helping families and firefighters see where they are going in the event of a fire. 

Types of Fire-Resistant Drywall

CertainTeed is committed to offering gypsum fire-rated drywall to help builders in fire-prone areas construct safer homes. We offer multiple products based on your building codes and construction requirements. 

Type X fire-rated drywall has a gypsum core enclosed in ivory-colored face paper. This product is used in fire assemblies from 1 hour up to 4 hours. A one-hour fire-rated assembly is the standard for many building codes. Type X drywall is ⅝”(15.9mm) thick and installed on each side of nominal 2” x 4” (38x89mm) wood studs spaced 16” (400mm) off center (o.c.) or 3 ⅝” (610 mm) steel studs spaced 24” o.c. It has a minimum fire-rating for the assembly of 1 hour, which is a typical requirement for many building codes.
Type C fire-rated drywall also has a gypsum core enclosed in ivory-colored face paper. Sometimes referred to as Improved Type X, it is similar in composition to Type X, except that it has more glass fiber reinforcement and other ingredients in the gypsum core that makes its fire resistive properties superior to Type X. Type C gypsum board is available in ½” (12.7 mm) and ⅝” (15.9mm) thicknesses.
M2Tech® moisture- and mold-resistant drywall drywall is also available in Type X for enhanced fire resistance.
GlasRoc® Interior high-performance interior drywall features a special formulation, treated core, and fiberglass mat facer technology, designed to provide exceptional moisture, mold and fire protection for interior applications and exterior soffits.
GlasRoc® Shaftliner fire-rated drywall is a model of Type X that is made for multi-story buildings and multi-family residential apartments and condominiums. The thick gypsum board has a specially formulated fire-resistive, noncombustible, and moisture resistant core. This protects your home from mold and moisture as well as the spread of fire.
GlasRoc® Sheathing is an exterior-facing product made with cementitious glass mat facers that are embedded into a water-resistant gypsum core. This Type X exterior sheathing features excellent fire-resistance properties and numerous fire-rated assemblies.

Each of our fire-resistant drywall options is developed with specific climates and building types in mind. Browse our products to learn which ones are best for your area and building needs. With your careful planning and dedication to fire containment, you can help residents in your area keep their homes and businesses standing during wildfire season. 

Learn More About Fire-Resistant Drywall

What's the Difference Between Regular and Type X?
Do I Need Fire-Rated Drywall in My Home?
Where Can I Buy Fire-Rated Drywall?