Is wonderboard fire resistant?

This blog post will answer the question, “Is wonderboard fire-resistant” and cover topics like fire-resistant properties of wonderboard and frequently asked questions related to the topic.

Is wonderboard fire resistant?

Yes, the wonderboard is fire-resistant. It provides fire protection. 

What Is A Wonderboard?

If you think of a wonderboard when you think of construction materials, the backing board is the very first thing that comes to mind.

And if that’s the case, then kudos to you; you’re on the correct course. Wonderboard is a unique type of material that is utilized to construct the base of the wonderland’s numerous luxury residences.

When people think of backing boards, they usually think of their main element, cement, which is what makes them cement supporting boards. Wonderboards are cement-based boards with certain additional qualities and advantages above standard cement boards.

Wonderboards are 20 percent lighter and easier to carry and load since they are comprised of Cement concrete with mesh-reinforced fiberglass. 

Furthermore, they are more versatile and adaptable for a variety of uses, allowing them to be utilized in any room of the home without cutting.

This is conceivable because they have a less firm facility than other kinds of boards, such as hardibacker or durock.

Is Wonderboard a fire-retardant material?

Yes, the wonderboard is fire-resistant. The official statement about the wonder board’s fire-prevention function is that they are non-combustible. 

However, except for the phrase “flammability,” nothing is said specifically regarding the wonder board’s fire resistance.

The lesser the flammability, the stronger the fire resistance, and the greater the flammability, the lower the fire resistance.

The phrases combustion and flammability are often misunderstood. In the event of a thing igniting and catching fire, they are not the same. The same can be said for the concrete-based wonderboards that make up the floors, walls, & ceilings of your home.

To put it another way, all combustible items are flammable, but not all flammable items are explosive. The key point here is that a combustible item is always non-fire resistant, but a non-combustible object may be both fire-resistant and non-fire resistant.

The reason for this is because an item is regarded flammable if it ignites between 32.8degrees Centigrade and 93.3° Fahrenheit, and it is considered combustible if it burns between 32.8degrees Centigrade and 93.3°F.

Because wonderboard is non-combustible, it may be both flammable and non-flammable. If it was combustible, there would be no other choice but to be flammable. The wonderboards, on the other hand, do not follow this pattern.

As a non-combustible material, the wonderboard is clearly fire-resistant.

What Is The Wonderboard’s Melting Point?

Now, if we shift our attention to a new issue, followed by the combustion of the Wonderboard, we may bring the melting process to a halt.

Melting is a basic characteristic of matter that occurs when solids are exposed to greater temperatures. The loss of molecular energy of bondings causes a solid to change into a liquid. 

As a consequence, a solid becomes a liquid, similar to how a drink becomes a gas when exposed to even more heat.

Melting occurs, followed by ignition, which occurs after the substance’s flashpoint is surpassed. However, passing the flashpoint will not result in instant melting. 

The flashpoint, which is also the same for the wonderboards of your home’s base, is the first step of the melting process.

In the case of the external wonderboards, they are paired with metal frameworks such as steel. As a consequence, all of the outside components are almost fireproof. It’s possible that their flashpoints are connected.

That is to say, the wonder board’s flashpoint is almost identical to the flashpoint of steel.

Wonderboard’s Advantages, Disadvantages, and Costs

As is customary, we’d like to provide a quick purchasing guide for the wonderboard, including benefits, disadvantages, and expenses.

Pros of wonderboard:

Wonderboard is a wonderful shower backing board because of its moisture resistance and ability to tolerate fire threats. They are more flexible and lightweight than other concrete-based board kinds.

Cons of wonderboard:

The disadvantages are almost identical to those of the most well-known and reputable supporting boards, such as increased cost and upkeep.


The cost per square foot of wonderboard is $1.06, which adds up to $4.33 when labor expenses are included in.

Wonderboard: At what temperature does it burns?

The wonderboard, like other concrete-based non-flammable backing boards, does not have a burning temperature.

You didn’t say if you’re utilizing the wonderboards for the inside or outside of your home in the first place. 

Because it is a sort of supporting board that can be used as both the outside and the inside at the same time, the temp of their burning differs in the same manner.

Although the precise temp point is unclear, it is important to note that wonderboards burn quicker or at a lower temp in the interiors. This is because the outside substrates’ boiling temperature is greater, exceeding 1500°F, which is the same as a home fire.

What Happens If You Burn The Wonderboard?

Wonderboard release toxic compounds when it is burned. Due to the engagement of multiple material kinds, Wonderboards have certain unique characteristics, such as a 20 percent lower weight & flexible interference.

If these features are somehow burnt, the feedback for these features must also be paid once. As a consequence, the fiberglass breaks down, releasing potentially toxic compounds in the form of smoke.

When the dust from the cement and the glassware within the board is burned, it may create a variety of health problems as well as pollution.

Wonderboard vs. Hardibacker

Comparison between both can be understood by the following points:

  • Use
  • Properties
  • Cut and form
  • Price
  • Composition

I will now elaborate on the guidance given above.


WonderBoard’s products are virtually as durable as HardieBacker’s normal range. As a result, WonderBoard is more suited to moist environments than HardieBacker.

While HardieBacker offers a waterproof line called HardieBacker HydroDefense, the majority of their products are just water-resistant rather than entirely waterproof. As a result, they must utilize extra waterproof sealants while installing HardieBacker.

Meanwhile, WonderBoard’s whole product line is completely water-resistant. As a consequence, WonderBoard may be used both inside and outdoors, while HardieBacker should only be used indoors and never outdoors.


In general, the breaking strength of concrete boards is much higher than that of previously used plywood & gypsum boards. Concrete boards may last up to 50 years if they are properly protected & managed. 

Furthermore, cement boards are more sturdy and resistant since they are less prone to shrink.

To be honest, both HardieBacker & WonderBoard are water-resistant to some extent. However, because of the various materials, this results in them having diverse characteristics. 

In particular, HardieBacker is constructed of cellulose fibers & cement rather than pure cement, whereas WonderBoard is almost all made of cement.

As a consequence, HardieBacker is more versatile and lighter than its rival. It also makes installation more approachable and effective without jeopardizing the quality of the product. Finally, HardieBacker makes cleaning a lot simpler.

Cut and form

WonderBoard contains Cement & fiberglass supporting strands, among other materials. Furthermore, WonderBoard makes cutting difficult owing to the mesh. In fact, WonderBoard is more likely to shatter, especially when cutting off little sections.

As a result, the manufacturer recommends cutting it with a blade, much like cutting drywall. You may also use a circular saw to cut it. 

Unfortunately, it rapidly dulls saws blades, so experts recommend keeping replacements on hand, and when using a power saw, it creates clouds of cement dust, necessitating the use of a respirator & glasses.

HardieBacker, on the other hand, is easier to cut & shape than WonderBoard. As a result, following the pre-cut grid pattern while cutting makes HardieBacker’s smooth cutting experience even simpler.


Specific pricing is difficult to explain since they are dependent on a variety of criteria such as retailers, thickness, product line, and so on. In general, WonderBoard is less expensive than HardieBacker.

A 3ft × 5ft piece of HardieBacker board with a 1/4 inch thickness, for example, costs about $12. A WonderBoard piece of the same size, on the other hand, costs about $10. As a result, WonderBoard was $2 less expensive than HardieBacker.


The most notable difference between HardieBacker & WonderBoard Lite is their composition. HardieBacker is a 90 percent Concrete, sand, and 10percent cellulose fiber blend with patented performance additives.

WonderBoard, on the other hand, is a mesh-reinforced cement and fiberglass composite. Furthermore, it lacks fiber and gypsum, reducing the backer board’s longevity.

Which Is Better: Hardibacker or Wonderboard?

It’s impossible to say which of these two companies’ cement backer boards is superior after comparing them, even if they fulfill identical objectives. However, since their qualities aren’t identical, they’ll be better suited to distinct applications.

In summary, the HardieBacker’s minimal weight makes it perfect for smaller jobs or situations where individuals must work alone. Meanwhile, the WonderBoard, which is hefty yet long-lasting, provides a firm foundation for your floors and walls.

When it comes to covering a broad area, WonderBoard is superior since it is more durable and cost-effective (walls or floor). HardieBacker, on the other hand, is a superior choice for small spaces like bathroom walls or vanity tops. 

HardieBacker is also simpler to work with and less likely to fracture when sliced into little pieces.

In addition, HardieBacker is better for delicate materials like vinyl & enamel, while WonderBoard may harm your installation or tub.

Frequently Asked Questions(FAQs), “Is wonderboard fire resistant?”

What do you do with WonderBoard?

Walls, roofs, floors, patios, worktops, and vanities may all benefit from WonderBoard Lite. Underneath any brick or natural stone, use this. 

Over cement or gypsum substrates, this product is not recommended. WonderBoard Lite should not be utilized as a load-bearing structural component.

Can I build a fireplace out of a cement board?

A Hardiebacker board may be used to surround your fireplace. However, fiber cement boards, such as Hardie board, may be used in places like the fireplace and furnace surround.

What is WonderBoard, exactly?

Wonderboard is a solid concrete board with a mesh face for added strength. -brittle. 

It’s easy to break tiny strands if you cut them into them. -cutting With a portable carbide cutter and snap, score the surface & cut the mesh reinforcement, or cut with a diamond blade.

Is it possible to paint WonderBoard?

If you don’t completely clean a cement board before painting it, you can have adhesion issues. Fibrous cement boards, unlike normal cement, which isn’t the best surface for paint adherence, have pores that soak up the glue in the paint, rendering the finish far more durable.

What is the difference between WonderBoard and Backer Board?

The composition of HardieBacker & WonderBoard Lite is the most significant distinction. WonderBoard is constructed of a cement combination reinforced by mesh, while HardieBacker is made of a mixture of concrete, sand, and cellulose fibers.

Is it possible to use cement board as a subfloor?

No, Hardie cemented board isn’t designed to be a structural material, and it won’t function as a substitute for a subfloor. The board is quite strong in compression and very stable, preventing the tiles from cracking, but it has very low shear strength.

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