How fireproof is cement board?

Author: Prof. Jaden Klocko  |  Last update: Saturday, April 19, 2025

While cement board is highly resistant to fire, it is not completely fireproof. Over prolonged exposure to intense heat, even cement board will eventually begin to deteriorate. However, its ability to resist fire for an extended period makes it an invaluable component in fire-rated assemblies.

What temperature can cement board withstand?

A high density cement board reinforced with inorganic fibers, NAD-11 is suitable for applications requiring continuous operation in temperatures up to 500°C (932°F). NAD-11 is dimensionally stabile, non-combustible, chemically inert, and it retains its mechanical strength at temperature.

Can I use cement board around a fireplace?

A: Yes, HardieBacker board can be used as a fireplace facing. HardieBacker 1/4'' board can be used as a component in a 1-hour fire resistive construction when installed in compliance with National Evaluation Report NER-405. HardieBacker boards are recognized as non-combustible, when tested according to ASTM E 136.

Is cement sheeting fireproof?

Fibre cement cladding offers excellent levels of safety as it is non-combustible. Plus, it has a fire protection rating of A2-s1, dO. This fire protection rating applies when the fibre cement cladding is installed with joints between boards up to a maximum of 3mm.

Is the HardieBacker 500 cement board fireproof?

HardieBacker® cement board has been evaluated by the BBA and approved with certificate no. 04/4100. The products meet the European standard for fibre cement - EN 12467 and its reaction to fire, in accordance with EN 13501-1, is A1,S1-d0. The product is therefore classified as fully non-combustible.

How Fireproof is HardieBacker Cement Board

Can I use cement board behind my wood stove?

The industry's solution for heat shields

By using an approved heat shield system, the required distance between the stove and adjacent wall can be significantly reduced. PermaBASE® Building Products are the industry-preferred choice and the only cement board approved for heat shield applications.

Can cement board be used as a fire barrier?

Yes, HardieBacker® 1/4" Cement Board is deemed noncombustible when tested to ASTM E 136 and can be used in conjunction with other noncombustible materials around a fireplace.

Can I use cement board as a heat shield?

The industry's solution for heat shields

PermaBASE cement boards are the industry-preferred choice. Installation-ready and easy-to-use, PermaBASE® cement boards eliminate the need for field fabrication, saving time while allowing for enhanced performance and wood-burning stove placement closer to the wall.

What material to use behind a fireplace?

Fireplace Surrounds Need to be Non-combustible

The fireplace mantel can be made out of any material (as long as it is far enough away from the firebox opening). However, the hearth and surround need to be non-combustible. Non-combustible materials include tile, stone, and brick.

What cement is fire proof?

Fireproof concrete has several residential and industrial applications. Commercially it is made with Portland cement and fly ash. However, you can also make fireproof concrete with just a few materials available at any home improvement store.

How thick should cement board be for fireplace?

HardieBacker® 12mm cement backerboard is fire rated class A1, meaning the product is non-combustible. HardieBacker® 12mm cement backerboard is CE approved and BBA certified since May 2004. Hardiebacker say it is fine for up to 100 degrees centigrade (it will not set on fire but can crack).

Does heat transfer through cement board?

Cement board typically has a thermal conductivity (k-value) ranging from 0.18 to 0.35 Watts per metre-Kelvin (W/mK). Compared to concrete (1.0-1.8 W/mK), this relatively low thermal conductivity allows cement boards to provide some insulation value.

Is Durock fireproof?

Superior Strength and Durability. DUROCK Next Gen Cement Board's high compressive strength offers damage and impact resistance while maintaining dimensional stability and does not delaminate. Fire Resistance. DUROCK Next Gen Cement Board is a non-combustible panel and meets CAN/ULC S114 and ASTM E136.

Does it matter which side of the hardie board faces out?

Install smooth side up. Install HardieBacker boards perpendicular to subfloor panels. Never allow all four corners of boards to meet at one point.

What is the fire test for cement board?

One of the most commonly used standards is the ASTM E119 test, which assesses the fire-resistance properties of building materials. In this test, cement board is subjected to a controlled fire environment to determine how long it can withstand fire exposure without losing its structural integrity.

Is cement board better than drywall for fireplace?

The cement board is more ideal to use rather than drywall, as it is way stronger and has a porous surface ideal for the masonry adhesive to really stick.

Is cement board considered non-combustible?

Non-combustible materials are building materials that do not burn or ignite when subjected to expected levels of fire or heat. Examples of non-combustible materials include brick masonry, concrete blocks, hardy backer board, calcium silicate board, cement board, metal, and certain types of glass.

Is cement sheet heat proof?

Please be aware that FC or fibre cement sheeting is not recommended to be used near hot or open flame areas. Even though FC sheeting is a non- flammable material, It has a tendency to pop and explode into sharp pieces under prolonged exposure to heat.

Is cement board OK for fireplace?

The benefits of using PermaBASE Cement Board on fireplace insert surrounds include: Durability: Comes with a lifetime limited warranty for residential interior applications. Design flexibility: Ideal substrate for direct-applied veneers. Time savings: Lightweight and easy to cut for speedy installation.

How to fireproof a fireplace?

Use metal screen material with openings no smaller than 3/8-inch and no larger than 1/2-inch to prevent embers from escaping and igniting a fire. Keep closed seasonally: Close the fireplace flue during wildfire season when the chimney is not being used.

Is Hardie cement board fireproof?

James Hardie fiber cement siding panels are considered masonry products. So, they have all the same attributes as stone, brick, and stucco, including fire-resistance.

What fire rating is cement board?

Suitable for internal and external use. Impervious to moisture and A1 Fire Rated.

How do you make cement fireproof?

Improving the fire resistance of concrete
  1. Applying a heat coated in intumescent paint.
  2. Applying a layer of lightweight mortar to exposed concrete surfaces.
  3. Protecting concrete surfaces with board systems.

Can cement board withstand heat?

Performance in Extreme Heat

Fiber cement boards are non-combustible and can withstand high temperatures without losing their structural integrity. This makes them suitable for areas prone to extreme heat and fire hazards.

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