How fire resistant is our building?

This blog post will answer the question, “How fire resistant is our building” and cover topics like flammability of building materials and frequently asked questions related to the topic.

How fire resistant is our building?

Buildings are fire-resistant up to a limit. One of the most popular building materials, concrete, is also a great fire-resistant option. It is noncombustible and has a low thermal conductivity, which means that fire takes a long time to influence its structural, load-bearing capabilities and that it guards against fire spread.

Understanding the qualities of construction materials that withstand fire

Examining structural materials for their potential to prevent flame passage is an important part of a good passive fire prevention approach. This guarantees that a building is properly protected in the event of a fire, following strict building and construction rules.

When selecting the correct fire-resistant material, a variety of criteria are taken into account, including load-bearing capacity, thermal conductivity, and decay resistance. We’ll go through the precise fire-resistance qualities of typical construction materials given below: 

  • Mortar and Brick
  • Stone
  • Timber
  • Steel
  • Concrete
  • Glass
  • Iron (cast)

I will now elaborate on the guidance given above.

Mortar and Brick

Individual bricks have exceptional heat resistance, with the potential to tolerate temperatures of up to 1200 °C. The fact that bricks are often manufactured in a fire kiln is one of the most widely stated reasons for their high fire-resistance rating.

However, mortar, which is less efficient as a fire-resistant substance, is often used to hold brick walls together. Mortar is a masonry component material that is used to fill the spaces between the blocks and bricks that join together to form walls.

Because the components used to manufacture mortar (typically a combination of clay, cement, lime, and sand) are resistant to fire and heat, most mortar is fire resistant to some degree. A significant rise in temperature, on the other hand, may cause the mortar to crack and expand. Despite this, brick has remained the most popular fire-resistant construction material, with exterior walls and other conventional building features frequently employed.


When exposed to fire, stone suffers and is prone to disintegration when rapidly cooled. The exothermic reactions vary widely depending on the kind of stone. Granite, for example, explodes when heated, necessitating substantial risk management when used as a building material. While high heat may cause limestone to fracture, sandstone’s particular composition (tiny mineral particles and rock fragments) allows it to endure moderate fires and is less prone to cracking and breaking apart than other stone materials.


Even though wood is a frequent heat conductor, the lumber utilized in heavy construction may be relatively fire-resistant. When surface compounds like ammonium phosphate, sulfate, and zinc chloride are added to building materials, their fire resistance levels typically vary. Paint may be applied to wood to provide an extra layer of fire resistance. This emphasizes the need to distinguish between raw and structural materials (that have often been treated as part of the design and construction process).

Fire-retardant materials should not be confused with fire-resistant materials. Compared to more combustible competitors such as plywood and fiberboard, fire-retardant materials are engineered to burn significantly more slowly.


Steel is well-known for its great tensile strength and long-term structural integrity. Steel structures are resistant to termites, corrosion, and decay, and can survive the elements. Steel, on the other hand, is not as resistant to fire temperatures. Steel beams droop and columns buckle when exposed to fire for too long, causing the building to collapse. Mild steel can be stressed at temperatures above 600 °C, and steel will completely melt at temperatures above 1400 °C.

As a result, fire safety is an important consideration in the construction of steel buildings. Fire safety professionals should be consulted early on by site owners and project managers. These specialists may then propose solutions to increase structural steel’s fire-resistance rating, such as intumescent paint. When exposed to severe temperatures, this paint creates a carbonaceous coating, providing an extra layer of protection for steel beams. Consult our guide on structural steel fireproofing for further information.


The mix of components in concrete determines how it reacts to high temperatures. This means that the fire resistance of architectural materials is influenced by the quality of the cement and aggregates utilized. Reinforced concrete can usually withstand temperatures of up to 1000°C for around sixty minutes before losing its strength. In our guide on concrete building fire resistance, we go over this topic in further depth.


When glass is subjected to heat and then allowed to cool, it cracks and shatters, much like stone. As a result, site personnel will often utilize reinforced, toughened, and laminated glasses for safety reasons. These glasses are significantly more fire-resistant than standard glass, particularly those with steel wire.

Iron (cast)

Cast iron isn’t often utilized as a construction material. This is due to its behavior when exposed to high temperatures. Cast iron will break into fragments when exposed to heat and then quickly cooled. As a result, it’s usually covered with brickwork or another more sturdy fire-resistant material, such as concrete.

Fire-resistant materials are treated to make them more resistant to high temperatures. Fireproofing is a method of greatly reducing their susceptibility to no substance that cannot be destroyed by the impact of heat. Passive fire prevention is crucial for this reason.

Choosing the correct materials is simply one aspect of preventing fires in buildings. If you’re interested in learning more, we suggest starting with our article on fire-prevention structural measures.

The Top 6 Fire-Resistant Construction Materials

We’ll look at some of the best materials for avoiding and putting out a fire.

  •  Natural Products That Have Been Flame-Treated
  • Windows with fire-resistant glass
  • Stucco 
  • Gypsum

I will now elaborate on the guidance given above.

Natural Products That Have Been Flame-Treated

In contrast to solid concrete and plaster, natural building materials such as timber and cotton often have low fire resistance. Plant-based materials are simple to burn and are swiftly devoured by flames. On the other hand, builders have access to sophisticated chemical treatments that may boost their resistance to fire, allowing them to withstand it for many minutes. Rather than being burned immediately, flame-treated wood forms a scorched barrier around its surface, slowing further combustion. This sort of wood is often utilized on outside elements that might catch sparks before they reach the inside of a property.

Treated cellulose insulation is also a flame-resistant alternative to fiberglass and cotton insulation. The cellulose is usually made from recycled paper and is treated chemically with borate fireproofing to make it less combustible than it would be in its natural state. After the insulation is sprayed into the walls, it does an excellent job of shielding heat from fires or hot weather.

Windows with fire-resistant glass

Windows are necessary for sight and light, but they may also be a fire hazard. A neighboring fire’s high heat may cause a window to shatter even before it comes into direct contact with flames. A shattered window also enables the fire to readily enter a structure. Furthermore, the heat from a fire outside may be sufficient to ignite combustible materials within a residence without the need for direct contact.

Consider adding fire-resistant windows to safeguard your home. Dual-paned glass windows, for example, provide energy efficiency while also doubling the time it takes for a fire to burst through the panes. The exterior layer will be the first to crack, followed by the inner layer. Tempered glass is also effective since it has been heat-treated to make it four times stronger than plain glass.

Glass blocks are incredibly fire-resistant while still giving light, even though they don’t give visibility. The best option is wired glass, which is tempered glass reinforced with metal wire. Wired glass windows are often used indoors that need both fire protection and visibility.

It’s also worth mentioning the significance of window framing. The steel framework, followed by wood and aluminum, provides the greatest fire protection. The least effective is vinyl. Stucco


Stucco is a kind of plaster that has been used for both aesthetic and structural reasons for ages. Modern stucco is a fire-resistant finish compound consisting of Portland cement, sand, and lime that serves as an effective and long-lasting finish for structures. Any structural material, such as brick or wood, may be covered. Two or three coatings are commonly applied over metal reinforcing mesh. A one-inch (2.54-centimeter) coating of stucco may easily provide a wall or ceiling with a one-hour fire rating, indicating that it will take an hour to catch fire.

Roof eaves (overhangs) are a fire threat that may be mitigated by encasing them in fire-resistant material. Stucco is often suggested as one of the finest materials for boxing in potentially dangerous eaves.

Stop the fire and keep your style.

Stucco may be painted in a variety of colors and textures due to the adaptability of finishing procedures. As a result, it may readily be adapted to a variety of architectural styles, including Prairie School, Mediterranean, Tudor, and Southwestern. This way, you won’t have to choose between beauty and practical fire resistance.


To get a satisfactory fire-resistant rating, many structural materials will need underlying gypsum sheathing, and the gypsum board is the most commonly used fire-resistant interior finish. A Gypsum board, sometimes called drywall, is made out of a gypsum layer sandwiched between two sheets of paper. Type X gypsum board has been treated with chemicals to strengthen its fire resistance even further.

The paper on the type X gypsum board’s outside burns slowly and does not contribute to the spread of the fire. Furthermore, the gypsum board has a noncombustible core made up of chemically mixed water (in calcium sulfate). When water is exposed to fire, the first thing that occurs is that it turns into steam. This efficiently prevents heat from passing through the gypsum board. Even after the water has evaporated, the gypsum core resists fire penetration for some time. To boost the fire-resistance rating, builders often utilize many layers of gypsum board.

Frequently Asked Questions(FAQs), “How fire resistant is our building?”

Is fire resistance possible?

Although it is difficult to develop a completely fireproof dwelling, experts are currently concentrating their efforts on building homes that are at least fire-resistant. Last year, wildfires burned more houses and structures in the United States than at any previous time in history.

Why is fire resistance important?

The fire resistance of concrete increases the safety of inhabitants, firefighters, and neighbors during fires and reduces damage, allowing buildings to swiftly reopen, and enhancing community resilience.

What buildings are fire resistant and what makes them fire resistant?

One of the most prevalent construction materials, concrete, is also a great fire-resistant option. It is noncombustible and has a low thermal conductivity, which means that fire takes a long time to influence its structural, load-bearing capabilities and that it guards against fire spread.

What are the effects of fire on building materials?

The assessment of fire’s influence on building materials is crucial from a scientific and socioeconomic standpoint, since fire may cause chemical and mechanical changes in materials, resulting in structural stability issues in historical and/or contemporary structures.

What impact can fire have on common building materials?

What are the effects of fire on popular construction materials? Some materials, such as wood and plastic, will contribute to the spread of the fire. Concrete and masonry, for example, will stop or slow the spread of the fire. When exposed to the heat of a fire, all materials respond differently.

How does fire spread in buildings?

The heat created by fire rises naturally, but when it reaches the ceiling in a confined place like an office, it gets trapped. The heat then spreads horizontally, allowing the fire to spread across the whole area.


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