x
 
 
Learn which plants thrive in your Hardiness Zone with our new interactive map!

Why Does a Concrete Floor Get Hot?

By Isaiah David

Concrete floors in general don't get especially hot. In fact, as we will see later in this article, concrete is known for staying cool. One exception, however, is during the curing process. Concrete begins as a powder, consisting of cement, sand, gravel and other materials. When that powder is mixed with water, it starts a chemical reaction which turns the concrete into a solid, rock-like substance. This is an exothermic reaction, which means it produces heat. If the layer of concrete is thin, it only produces a bit of heat. A really thick, heavy concrete floor, however, will produce more heat over a longer period of time, and that heat can take a while to all flow out into the air.

Curing

Concrete floors in general don't get especially hot. In fact, as we will see later in this article, concrete is known for staying cool. One exception, however, is during the curing process. Concrete begins as a powder, consisting of cement, sand, gravel and other materials. When that powder is mixed with water, it starts a chemical reaction which turns the concrete into a solid, rock-like substance. This is an exothermic reaction, which means it produces heat. If the layer of concrete is thin, it only produces a bit of heat. A really thick, heavy concrete floor, however, will produce more heat over a longer period of time, and that heat can take a while to all flow out into the air.

Thermal Mass

When a material absorbs energy, it heats up. The more material there is in a structure, the more energy it has to absorb to heat up. Because a concrete floor is heavy and dense, it will have to absorb a lot of heat energy to heat up. If that floor is subjected to warm temperatures during the day, it may continue to absorb heat all day long, never quite catching up to the air temperature. This will make the concrete actually feel cool during the day.

Releasing the Heat

When the air cools down in the evening, however, the thermal mass of the concrete floor will make it feel warm. All the energy that the concrete stored up during the day will be slowly released during the night. How hot the concrete floor feels depends on the difference between daytime temperature and nighttime temperature. If the concrete is heated a lot during the day and the temperature drops sharply at night, it can feel quite warm, or even hot for a few hours.

 

About the Author

 

Isaiah David is a freelance writer and musician living in Portland, Ore. He has over five years experience as a professional writer and has been published on various online outlets. He holds a degree in creative writing from the University of Michigan.