Is cement board considered fireproof?

Author: Randal Schroeder  |  Last update: Saturday, June 14, 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.

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.

How fireproof is a hardie plank?

Hardie® products have a Class A fire rating when tested in accordance with ASTM E84, with a flame spread index of 0. And they're eligible to be used in certain 1-hour fire rated wall assemblies which may be required under local building codes.

Is Durock cement board fire rated?

Durock Cement Board has excellent fire-resistant properties, making it a reliable choice for construction projects that require fire protection.

Is Concrete Board Fireproof? - Civil Engineering Explained

How fire-resistant is cement board?

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.

Is normal cement fireproof?

Concrete is proven to have a high degree of fire resistance and, in the majority of applications, can be described as virtually fireproof.

Is 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.

Does cement board resist heat?

Cement board siding is a poor insulator and absorbs a considerable amount of heat in warm months. This excess heat permeates the interior of your home, compelling air conditioning systems to work overtime and leading to increased energy expenditures.

Is Hardie board 1 hour fire rated?

The Hardie board fire rating itself is not 1-hour fire rated. However it can qualify for use in certain 1-hour fire rated assemblies. Hardie Backer board is another product used as an underlayment for tile and stone installations. It provides a strong surface to prevent cracks and damage to the finished surface.

What is the fire rating of cement fiber board?

Fibre cement cladding from James Hardie has a fire rating of A2, s1 d0, which is the highest possible fire rating for a coloured cladding board. This means that it is a non-combustible cladding and will not ignite when exposed to direct flame or extreme heat, nor will it contribute fuel to a fire.

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.

What house material is fire proof?

Exterior walls can be protected by fire-resistant materials such as: cement, plaster, and stucco. concrete masonry such as stone, brick, or concrete block.

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.

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 cement board fireproof?

Cement board or Hardi are not approved fire proofing materials as far as I know. They are not flammable but their cement composition readily transmits the heat of a fire through a wall. The water chemically bound in gypsum (sheetrock) is liberated by a fire's heat.

Can cement board be used as a fireplace surround?

PermaBASE® Cement Board offers a simpler, cleaner way to install fireplace insert surrounds that saves installation time. The boards arrive ready to be installed, no jobsite preparation needed.

What is the maximum temperature for cement board?

H91 Cement Board Physical Properties:

Operating Temp - 1292º F/700º C. Compressive Strength - 16,675 psi ambient 15,310 psi (24 hrs @ 700º F) 14,020 psi (24 hrs @ 1000º F) Electrical Strength - 1.83 Kv/mm in air @ 200° F.

What is the difference between Hardie board and cement board?

There are two major differences between the two for homeowners to consider: Hardie board is more lightweight and cement board is less expensive. If you're learning how to install fiber cement siding yourself, Hardie board might be a better option as it would be easier to manage compared to traditional 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.

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.

What can I mix with cement to make it fireproof?

Instructions: STEP 1 – Wear appropriate safety gear, including a mask and gloves, as some materials can be irritating. STEP 2 – A common ratio is 1 part Portland cement, 1 part lime, 4 parts sand, and 1 part fire clay.

How thick does a concrete wall need to be for a 2 hour fire rating?

The fire-resistance rating of concrete masonry walls depends on the type of aggregate used in the units. A 2-hour rating can be achieved by a wall with an equivalent thickness of as little as 3 1/5 inches when expanded slag or pumice is used or 4 1/2 inches when siliceous gravel is used as the aggregate.

Which cement is called fireproof cement?

The refractory cement is a type of newly developed material that has excellent heat-resistant performance and is widely used in the industrial field.

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