
20 Jul A Complete Guide to Fire Resistant Wallboard Types, Standards, and Ratings
Table of Contents
Fire resistant wallboard is a shield that slows fire in buildings. People use this material to stop flames from spreading fast. It gives people more time to get out and lowers damage. Fire resistant wallboard is important for passive fire protection. Building codes like the IBC and NFPA require it. If you install it the right way, you follow fire safety rules. This also helps your building pass inspections. Using fire resistant wallboard can help save lives and property in a fire.
Key Takeaways
Fire resistant wallboard helps slow down fire. This gives people more time to get out. It also helps lower damage from fire. – Type X and Type C drywall have different fire resistance. Type C is stronger than Type X. But Type C costs more money. – Magnesium wallboard can resist fire, water, and mold. This makes it good for wet or busy places. – Fire resistance ratings like 1-hour or 2-hour tell how long walls last in fire. – You must install and seal fire rated drywall the right way. This keeps fire protection strong and helps pass inspections.
Fire Resistant Wallboard
What It Is
You use fire resistant wallboard to protect buildings from fire. This material looks like regular drywall, but it has special features. Manufacturers add glass fibers and other non-combustible materials to make it strong against heat. When you install fire rated drywall, you create a barrier that slows down fire. This wallboard comes in different types, such as fire rated drywall Type X and fire rated drywall Type C. Each type has a specific rated time for holding back fire, like 1-hour or 2-hour rated walls. You often see fire resistant drywall in places where fire safety is critical, such as stairwells, corridors, and between units in apartments.
Fire rated drywall is thicker and denser than standard drywall. The extra thickness helps the wallboard resist fire for a longer time. You can find fire rated drywall in both residential and commercial buildings. Builders use it to meet fire safety codes and to protect people and property. Fire resistant wallboard is a key part of passive fire protection. It works with other rated materials to keep fire from spreading quickly.
Why It Matters
Fire can move fast and cause a lot of damage. When you use fire rated drywall, you help slow down the spread of fire. This gives everyone more time to leave the building safely. Fire resistant drywall keeps fire contained in one area, so it does not reach other parts of the building right away. You also protect valuable property and important assets by using fire rated drywall in your walls.
Fire rated drywall is not just about following rules. It shows you care about fire safety and the well-being of everyone in the building.
Here are some key benefits you get from using fire resistant wallboard:
Fire rated drywall withstands high temperatures and slows fire, giving you more time to evacuate.
The non-combustible core helps keep fire in one area, reducing the risk of spreading.
Fire rated drywall protects the structure and contents from fire damage.
You meet building codes when you use fire rated drywall in required areas.
Insurance companies may offer lower premiums for buildings with fire resistant drywall.
You give peace of mind to everyone who lives or works in the building.
When you choose fire rated drywall, you make your building safer. You also help ensure that your walls meet all fire safety standards. Fire resistant wallboard is a smart investment for any property.
Types of Fire Rated Wallboard
When you pick fire rated drywall, you have choices. Each type gives a different level of fire protection and strength. Some types cost more than others. Knowing these differences helps you pick the best drywall for your job. Here are the main types you can find.
Type X
Type X fire rated drywall is the most popular kind. It has a gypsum core with glass fibers inside. This makes the board strong when there is a fire. Type X is usually 5/8-inch thick, which is thicker than regular drywall. You see Type X in fire barriers, stairwells, and between apartments.
Composition: Gypsum core with glass fibers and tough paper.
Fire Resistance: Gives at least a 1-hour fire rating in a wall. Some walls can last up to 4 hours.
Applications: Used in homes and businesses. You find it in walls near garages, boiler rooms, and between apartments.
Cost: Type X costs about 30% more than regular drywall. You might pay $10 to $20 for each panel.
Type X fire rated drywall is a good deal and meets most building codes.
Drywall Type | Price Range per Sheet/Panel |
|---|---|
Standard Drywall | $8 to $20 |
Fire-resistant Type X | $10 to $20 |
Type X fire rated drywall is easy to put up and works well. You can use it in new buildings or when fixing old ones. It also meets green standards, using recycled paper and low VOCs.
Type C
Type C fire rated drywall is even stronger than Type X. It has more glass fibers and special stuff added. These extras help the board stay together and not crack in high heat. Type C comes in 1/2-inch and 5/8-inch thickness, so it is easier to carry.
Aspect | Type X Gypsum Board | Type C Gypsum Board |
|---|---|---|
Fire Resistance | Over 2 hours in the same tests, best in the industry | |
Composition | 5/8 inches thick; first fire code product | Thinner boards than Type X, easier to install |
Typical Applications | Used in shaft walls, stairwells, and firewalls | Works best when put up sideways; great for ceilings; not for every use |
Cost | Baseline for fire-rated drywall pricing | About 10% more expensive than Type X |
Installation Notes | Can be put up straight with the same fire rating | Fire rating drops if put up straight; best rating when sideways |
Common Usage | Used around boilers, garage walls, and house walls | Also used around boilers but needs special placement |
You often use Type C fire rated drywall for ceilings and places that need top fire safety. The extra stuff in Type C helps it last over 2 hours in fire tests. This makes it the best for tough fire-rated walls. But Type C costs up to twice as much as regular drywall and about 10% more than Type X.

Tip: Always put Type C fire rated drywall sideways for the best fire rating, especially on ceilings.
Magnesium Wallboard
Magnesium wallboard, or MgO board, is a newer choice for fire-rated drywall. It uses a magnesium oxide core with fiberglass mesh and stuff that keeps out water. This board is heavier and denser than gypsum fire rated drywall, but it has special benefits.
Feature | Magnesium Oxide (MgO) Board | Gypsum Board |
|---|---|---|
Core Composition | Magnesium oxide core; fiberglass mesh; water blockers | Calcium sulfate core; paper or fiberglass facing |
Density | 950-1050 Kg/m³; heavier and denser | 640-800 Kg/m³; lighter and easier to carry |
Impact Resistance | High; holds heavy screws; good for busy areas | Medium; not as tough |
Fire Resistance | A1 fire rating; does not burn; stands up to high heat | Fire resistant because of water but not as good as MgO |
Moisture Resistance | High; stops mold and mildew from growing | Can get damaged by water unless made stronger |
Typical Uses | Outside roofs, floors, fire-rated walls in homes and businesses | Regular inside walls |
Magnesium wallboard is special because it has an A1 fire rating. This means it does not burn or make bad smoke. You can use it in fire-rated walls for risky places like kitchens, bathrooms, laundry rooms, and outside walls. It fights water, mold, and hits better than gypsum fire rated drywall. But you will pay more for magnesium wallboard—up to $2.50 for each square foot. You may also need special tools to put it up.
Magnesium wallboard is great for fire barriers in places with heat, water, or lots of use.
Specialty Boards
You can also pick from special fire-rated drywall panels for unique needs. These include:
M2Tech®: Fights water, mold, and fire. Use it in bathrooms or kitchens where you need extra fire safety.
GlasRoc® Interior: Has a treated core and fiberglass mat for fire, water, and mold safety. You see it in fire-rated walls in hospitals and schools.
GlasRoc® Shaftliner: Thick, does not burn, and keeps out water. Use it in tall buildings for firewalls and elevator shafts.
GlasRoc® Sheathing: Made for outside fire-rated walls, this board uses glass mats and a water-safe gypsum core.
Special fire-rated drywall panels often have intumescent coatings. These coatings puff up when hot, making more fire barriers. You find these boards in offices, factories, warehouses, and data centers. They protect important equipment and help you follow strict fire codes.
Note: Always check the fire rating and certifications for special fire-rated drywall panels to make sure they fit your project.
Summary Table: Fire Rated Drywall Types
Wallboard Type | Fire Resistance | Moisture Resistance | Typical Uses | Cost Range |
|---|---|---|---|---|
Type X | 1-4 hours | Low | Fire-rated walls, barriers, ceilings | $10-$20/panel |
Type C | Over 2 hours | Low | Ceilings, high-demand firewalls | $28/panel |
Magnesium Wallboard | A1, up to 1200°F | High | Fire barriers, outside fire-rated walls, wet places | $1.50-$2.50/sq ft |
Specialty Boards | Varies | High (some types) | Data centers, hospitals, outside walls | Varies |
When you pick fire rated drywall, you make your building safer. You also follow the rules and help keep everyone safe.
Fire Resistance Ratings
1-Hour and 2-Hour Ratings
When you look at fire-rated assemblies, you often see 1-hour and 2-hour ratings. These ratings tell you how long a wall or ceiling can stand up to fire before it fails. A 1-hour rating means the assembly can keep its structure and stop fire from passing through for at least one hour. A 2-hour rating means it can do this for two hours. These ratings are not guesses. They come from strict tests that show how well the whole wall system works during a fire.
You use these ratings to meet building codes and keep people safe. For example, a 1-hour rated wall can protect an apartment or hallway, giving everyone more time to escape. A 2-hour rated wall is even stronger and is often used in places where fire risk is higher, like between different parts of a building or around stairwells.
Fire-rated assemblies use layers of materials like gypsum board, insulation, and special framing. Each part helps the wall resist fire. The rating shows how long the whole system can hold up under fire, not just one piece. You can find tested assemblies in UL designs, such as UL Design No. V340 for 1-hour ratings and U350A for 2-hour ratings. These designs help you build walls that meet fire protection ratings and pass inspections.
Tip: Always check the fire protection ratings for your project. Using the right rated assembly can save lives and protect property.
Testing Methods
You need to know how experts test fire-rated assemblies to understand what the ratings mean. The main test is ASTM E119. This test checks how long a wall, floor, or ceiling can resist fire. The test uses a furnace to heat the assembly to very high temperatures. The temperature starts at 68°F and rises quickly. At 5 minutes, it reaches 1000°F. At 10 minutes, it goes up to 1300°F. By 1 hour, the furnace is at 1700°F. At 2 hours, it hits 1850°F. Some tests last even longer, up to 8 hours and 2300°F.
During the test, the assembly must hold its shape, stop flames, and keep heat from passing through. Sometimes, testers spray the wall with water after the fire to see if it stays strong. This is called the hose stream test. If the assembly passes, it earns a fire resistance rating, like 1-hour or 2-hour.
ASTM E119 tests the whole assembly, not just one material. This means you get a real picture of how the wall will work in a fire. The test checks three things:
Structural strength – Can the wall hold up under weight during a fire?
Integrity – Does the wall stop flames and hot gases from getting through?
Insulation – Does the wall keep the other side cool enough to stop fire from spreading?
You can trust these ratings because they come from tough, repeatable tests. Building codes use these ratings to set rules for fire protection in homes and businesses.
Assembly Ratings
You might wonder about the difference between material ratings and assembly ratings. Material ratings look at how one product, like gypsum board, reacts to fire. They measure things like flame spread and smoke. These numbers help you pick materials that slow fire and make less smoke.
Assembly ratings go further. They test the whole wall system—gypsum board, studs, insulation, and any other layers—working together. The assembly rating tells you how long the complete wall can stop fire, keep its shape, and block heat. For example, a 5/8-inch Type X gypsum board helps, but the rating depends on how you build the whole wall.
You use assembly ratings to choose fire-rated assemblies that meet fire protection ratings for your project. These ratings are always given in time, like 1-hour or 2-hour. They show how long the wall can protect you during a fire. You find these ratings in UL listings and building code tables.
Note: Always use tested fire-rated assemblies, not just rated materials, to meet fire protection codes and keep your building safe.
Here is a quick table to help you see the difference:
What is Rated? | What It Measures | Example Use |
|---|---|---|
Material (e.g., gypsum board) | Flame spread, smoke, combustibility | Picking wallboard for fire safety |
Assembly (e.g., wall system) | Time to failure under fire (1-2 hours) | Building code compliance, fire barriers |
When you use the right fire-rated assemblies, you give your building the best chance to stand up to fire. You also make sure you meet all fire protection ratings and keep everyone safer.
Fire Resistant Wallboard Standards
When you choose fire resistant wallboard, you need to understand the standards that guide testing and certification. These standards help you know which products offer real fire protection and which ones meet code. You will see three main standards and codes: ASTM E119, UL 263, and the building codes from IBC and NFPA. Each one plays a key role in passive fire protection and helps you build strong barriers against fire.
ASTM E119
ASTM E119 sets the main rules for testing fire resistance in wallboard assemblies. You can trust this standard because it comes from a respected organization. Here is how ASTM E119 works:
Accredited labs test wallboard assemblies under controlled fire conditions.
The test checks how long the assembly can stop fire and keep its structure.
Third-party agencies, like UL or Intertek, review the results and give certification.
Manufacturers must keep their products the same as the tested version.
You can find certified products in published listings, which show they meet ASTM E119.
ASTM E119 focuses on the whole assembly, not just one material. This means you get a real measure of how your barriers will work in a fire. The standard helps you pick wallboard that supports passive fire protection and keeps people safe.
UL 263
UL 263 is another important standard for fire resistant wallboard. It uses almost the same testing steps as ASTM E119. Both standards use a time-temperature curve and test the assembly’s ability to stop fire, hold weight, and block heat. After the fire test, the wall faces a hose stream to check its strength. The main difference is the name and the group that issues the standard. You can use either UL 263 or ASTM E119 results to show your barriers meet fire protection needs.
Tip: Always look for UL or ASTM labels when you buy fire resistant wallboard. These labels show the product passed strict tests.
IBC and NFPA
You must also follow building codes like the International Building Code (IBC) and the National Fire Protection Association (NFPA) codes. These codes require you to use wallboard that meets fire resistance standards. They help you create barriers that slow fire and protect people.
You need to use compliant wallboard in homes, apartments, and businesses.
These codes lower your risk of legal trouble, fines, or delays.
Insurance companies may lower your rates if you use wallboard that meets these standards.
You help protect lives, property, and the building’s structure.
Note: Following these standards is not just about passing inspections. You help create safe spaces and support passive fire protection in every project.
Standard/Code | What It Covers | Why It Matters |
|---|---|---|
ASTM E119 | Fire resistance testing | Proves wallboard can stop fire |
UL 263 | Fire resistance testing | Confirms assembly strength and safety |
IBC/NFPA | Building code requirements | Ensures legal and safe construction |
When you follow these standards, you build strong barriers that support passive fire protection. You help keep everyone safe from fire, whether you work on a home or a large business.
Choosing the Right Wallboard
Building Type and Location
You have to pick fire rated drywall that matches your building. Each place needs a different kind of fire-rated drywall. In commercial buildings, people use gypsum-based fire rated drywall like Type X or Type C. These types can handle high heat and help keep people safe in a fire. At home, you still need fire rated drywall, but you should think about local fire dangers. If you live where wildfires happen, you might need extra fire-rated walls. Factories use fire rated drywall with steel frames or special coatings. This helps keep the building safe if there is a fire. The kind of building you have decides the fire resistance rating you need. It also affects how you put materials together and which codes you must follow.
Commercial buildings: Use fire rated drywall for walls and ceilings to meet strict codes.
Homes: Pick fire rated drywall based on local fire risks and use it with other fire-resistant materials.
Industrial sites: Use fire rated drywall with steel or coatings for strong fire-rated construction.
Code Requirements
You must follow building codes when you choose fire rated drywall. Codes tell you what kind of fire-rated walls you need for each building. For example, at home, codes often say you need fire rated drywall between the garage and the house. In apartment buildings, you need fire-rated drywall for walls and ceilings between units, hallways, and stairs. Offices and tall buildings need fire-rated drywall for exits and elevator shafts. Hospitals and schools use fire rated drywall to protect rooms and important spaces. Codes also say how long fire-rated walls must last, like 1-hour or 2-hour ratings. Always check your local codes because some places have tougher rules.
Building Type | Where to Use Fire Rated Drywall | Typical Ratings | Codes to Follow |
|---|---|---|---|
Home | Garage walls, ceilings, shared walls | 1-hour | IBC, NFPA, Local |
Commercial | Corridors, stairwells, elevator shafts | 1-3 hours | IBC, NFPA, Local |
Industrial | Walls with steel, fire-rated coatings | 2-4 hours | IBC, NFPA, Local |
Practical Tips
You can make better choices for fire rated drywall by using these tips:
Learn about the types of fire rated drywall, like Type X, Type C, and MGO boards.
Pick fire rated drywall that fits the room. For wet places, use MGO or Type C for mold and water safety.
Use the right thickness and layers to make fire protection and sound control better.
Look for safety labels and make sure your fire rated drywall meets building codes.
Choose eco-friendly fire rated drywall if you want to help the environment.
Buy from trusted brands and read reviews to see how fire rated drywall works in real buildings.
Plan your work. Cut fire rated drywall carefully and try not to waste pieces so your fire-rated walls stay strong.
Tip: Always follow the newest building codes and ask an expert if you are not sure which fire rated drywall to use for your home or project.
Installation and Mistakes
Best Practices
You want your fire rated drywall to give the best protection. Good installation makes a big difference. Follow these steps to get the most out of your fire rated drywall:
Pick the right type of fire rated drywall for your project. Use Type X, Type C, or special boards with extra fire resistance.
Use fire-resistant drywall tape, like fiberglass tape, on all seams and joints.
Apply a fire-resistant joint compound that matches your tape and drywall. Always follow the instructions from the manufacturer.
Clean the drywall surface and make sure seams line up well before you start taping.
Press the tape into a thin layer of joint compound. Smooth out any bubbles and feather the edges.
Let each coat of joint compound dry fully before adding the next. Sand between coats for a smooth finish.
Seal every joint, gap, and opening—like those around pipes, outlets, and windows—with fire-resistant caulk or sealant.
Add fire-resistant primers, paints, or coatings for extra protection if needed.
Always use the right tools and follow the directions for each product.
Inspect your work before finishing. Fix any gaps or rough spots.
Ask a professional for help with tricky jobs or repairs.
Check your fire rated drywall often and fix any damage right away.
Joints and gaps are weak spots. Sealing them well keeps fire, smoke, and heat from spreading.
Common Errors
Mistakes during installation can ruin the fire protection you expect from fire rated drywall. Watch out for these common errors:
Changing the design of a tested wall system, like moving studs or using the wrong fasteners. This can void the fire rating.
Skipping fire-stopping at joints, wall tops, or around pipes and wires. Gaps let fire and smoke pass through.
Forgetting to use fire-resistant insulation or barriers over foam or other flammable materials.
Not using mineral wool at key joints or wall connections.
Letting untrained workers install fire rated drywall. Poor skills lead to weak spots.
Failing to inspect the work before covering it up. Missed mistakes can stay hidden.
Breaking the ceiling membrane at wall joins, which can break the fire barrier.
Letting moisture get into the wallboard. Water can ruin fire resistance.
Assuming all fire rated drywall works the same. Only use products with tested ratings for your exact wall system.
Ignoring the manufacturer’s instructions or UL assembly details.
If you install fire rated drywall the wrong way, you risk failed inspections, costly repairs, and even losing insurance coverage. Gaps, cracks, or water damage can let fire spread faster and put lives at risk.
When you learn about fire resistant wallboard, you make buildings safer. You help stop fire from spreading and keep people safe. You also follow the rules that buildings must meet.
You can pick the best wallboard if you know about Type X, Type C, and other special boards.
You need to pay attention to fire ratings and rules like NFPA 101 and the International Building Code.
You should use trusted sources, like APA’s library, NRC Canada, and UL listings, to get more help.
Always talk to building experts and use the newest codes for your project. If you want to know more, look at guides and reports from top groups.
FAQ
What is the difference between fire resistant and regular drywall?
Fire resistant drywall has glass fibers and special additives. These help the board stand up to heat and slow fire. Regular drywall does not have these features. You use fire resistant drywall where codes require extra protection.
Can you paint over fire resistant wallboard?
Yes, you can paint over fire resistant wallboard. Use a primer first for the best results. Make sure the paint does not cover any fire rating labels. Always check the manufacturer’s instructions before painting.
How do you know if your wallboard meets fire codes?
Look for labels from UL, ASTM, or other trusted groups. These show the wallboard passed fire tests. You can also check the product’s paperwork or ask your supplier for proof of certification.
Where should you install fire rated drywall in a home?
You should install fire rated drywall in garages, between the garage and house, around furnaces, and on walls that separate living spaces from utility areas. Local codes may require more areas. Always check your local building rules.
Does fire resistant drywall stop smoke?
Fire resistant drywall slows fire and helps block smoke for a short time. It does not stop all smoke. You still need to seal joints and gaps with fire-resistant caulk. Smoke can move through small openings, so sealing is important.

1-Hour and 2-Hour Ratings
Building Type and Location