Fire-Resistant Building Materials

Concrete

Concrete, one of the most common building materials, is also an excellent fire-resistant material. It is non-combustible and has low thermal conductivity, meaning that it takes a long time for fire to affect its structural, load-bearing ability, and it protects from the spread of fire. It's actually significantly more fire-resistant than steel, and often used to reinforce and protect steel from fire.

However, it's important to note that not all concrete is created equal. It consists of cement and aggregate, and the particular kinds of aggregate materials used can vary, as well as the amount used. Aggregate can make up 60 to 80 percent of the concrete's volume {source: Ashley]. The exact fire-resistance properties change depending on the type and amount of aggregate used. Natural aggregates tend not to perform as well. Moisture in the aggregate can expand when heated, causing concrete to sinter after long exposure.

Concrete is often listed as among the best fire-resistant roofing materials, too. And you shouldn't overlook the roof as essential in fire-protection, since it's extremely vulnerable to sparks blown from wildland fire.

A more recent development in concrete construction is known as the Insulating Concrete Form (ICF). This structure is often used inside the walls of things like apartments and commercial buildings and consists of two polystyrene insulation panels with concrete poured between them. The completed material resembles a concrete sandwich, and is quick and cheap to construct, while offering a great balance of climate insulation, noise blocking and fire resistance.

Stucco

Stucco is a plaster that has been used for centuries for both artistic and structural purposes. Modern stucco is made of Portland cement, sand and lime, and it serves as an excellent and durable fire-resistant finish material for buildings. It can cover any structural material; such as brick or wood. It usually consists of two or three coats over metal reinforcing mesh. A 1-inch (2.54-centimeter) layer of stucco can easily lend a one-hour fire rating to a wall or ceiling, meaning it will take one hour to catch fire.

Roof eaves (overhangs) are a fire hazard, but they can be protected with an encasement of fire-resistant material. Stucco is often recommended as one of the best materials for boxing in hazardous eaves.

Gypsum

If we learned anything from the popular children's tale of the "Three Little Pigs," it's that you should make your house out of brick. This isn't such bad advice. Brick is not only resistant to a big bad wolf's huffing and puffing — it's also resistant to fires.

As bricks are made in a fire kiln, they're already highly resistant to fire. However, it's true that individual bricks are much more fire-resistant than a brick wall. A brick wall is held together with mortar, which is less effective. Nevertheless, brick is commonly cited as among the best building materials for fire protection [source: CLM]. Depending on the construction and thickness of the wall, a brick wall can achieve a one-hour to four-hour fire-resistance rating.

So, although some materials are more fire-resistant than others, several factors might influence a builder's decision, including cost effectiveness, ease of installation and climate.

Fire-Resistant FAQ

Is cement board fire-resistant?

Cement boards are fire resistant as they pass the required testing. Fibre Cement Boards are especially found to be non-combustible and, therefore can be used in conjunction with other non-combustible materials in building construction.

What is meant by fire resistant?

Fire resistance is the property of materials that prevents or delays the passage of excessive heat and fire. While no building materials are completely fireproof, it does take longer for fire to burn fire-resistant materials.

What materials are fire-resistant?

Various building materials are fire-resistant, but some of the best ones are fire-resistant glass windows, concrete, gypsum, stucco and brick.

What is a fire-resistance rating?

Building materials are rated according to how long it takes fire to cause damage to its structural ability and the material’s combustibility. This rating is known as a fire-resistance rating.

What is the most commonly used fire-resistant material for interior walls?

Gypsum board, also known as drywall, is the most commonly used fire-resistant interior finish. Type X gypsum board is treated with additives to improve its fire-resistance property, making it a popular choice.