Can Fire Damage Concrete?

We are often asked by customers, “Can fire damage concrete?” Unfortunately, many people are unaware that, not only is concrete susceptible to fires, its reaction to fire can be extremely detrimental to the entire structure.

Although concrete is one of the more flame-resistant materials, it can, in fact, become damaged during a fire. While the soot and smoke damage left on the concrete may appear to be simply an eyesore, it can actually be a sign that the structure of the building is in trouble.

Can Fire Damage Concrete?

When asking, “Can fire damage concrete?”, most homeowners want to know if damaged concrete is bigger than just an aesthetic problem. They want to know if, after the soot is scrubbed off and the stains are removed, does the concrete need to be repaired further?

The answer is yes. Fire-damaged concrete can be extremely dangerous.

Essentially, the effects of fire on concrete can weaken the integrity of a concrete structure. As concrete heats up past a certain point, the particles which make up a block of concrete begin to loosen. Because the sturdiness of a piece of concrete depends on the block to have tightly-packed particles, the structure of the block becomes weaker as it starts to loosen up.

While concrete structures are reinforced with rebar, there are still corners of each component that are left susceptible to overheating. Therefore, the corners of a fire damaged concrete slab are the part that start to crumble first. 

Can I Repair Fire-Damaged Concrete?

While you may want to contact a professional if you are trying to repair fire-damaged concrete, there are some steps you can take in the meantime. Start by using warm water and steel wool to remove the soot from the surface of the concrete. If you have access to a power-washer or strong hose, that will work as well.  

You can diagnose the damage by using a rebound hammer to measure the cracks in the concrete’s structure. Essentially a rebound hammer is designed to give you an idea of how much damage has occurred within any given piece of concrete. It will tell you if your concrete structure is in danger of collapsing and, therefore, if you should be worried or not.

If the damage is small enough, you can purchase some mortar to fill the cracks with. Mortar can be purchased at most hardware stores and will fill the empty spaces left by the slab’s expose to fire. To apply the mortar, you’ll mix the powder with water as outlined on the product packaging and apply it to the concrete with a trowel or plaster knife. It helps, in many cases, to saturate your concrete slab before applying the mortar to ensure that your repair bonds as best as possible.

Additionally, with smaller amounts of damage, a strengthening adhesive to repair cracks in the concrete. A good adhesive solution will basically “weld” the material back together by filling the empty space left during the concrete’s exposure to extreme temperatures. The adhesive will come with instructions on how to use it properly.

Important note: It is important to remember that DIY repair solutions should only be used when the concrete damage is minimal. If you fail to repair the crack well enough, you can risk making the situation worse. When in doubt, call a professional to have them assess the damage.

Next time somebody asks you, “Can fire damage concrete?”, you can tell them, “Yes! It does!” You may be able to help them repair the slab on their own or call a trained expert to prevent the concrete from deteriorating further.

Leave a comment