Why Does Concrete Develop Cracks From Water?

Water is both a friend and an enemy of concrete. When concrete is poured, water is essential for the curing process that makes it strong. But after the concrete has set, excess moisture can cause trouble. Water that seeps into tiny pores or cracks can react with the material, slowly breaking down the chemical bonds that hold it together.

As water moves through the concrete, it can carry away minerals, especially calcium hydroxide, which is a byproduct of the curing process. This leaching leaves behind a weaker, more porous structure. Over time, the surface can become soft and crumbly, and small hairline cracks may appear. These cracks then allow even more water to enter, creating a cycle of damage.

• Pore water expands when it freezes, creating internal pressure
• Repeated wet-dry cycles cause the concrete to swell and shrink
• Water dissolves the paste that binds sand and gravel together
• Soil beneath the slab can shift when it gets wet, causing uneven support
• Poor drainage lets water pool around the edges of the concrete
• Chemical reactions with water can form compounds that take up more space

In colder months, water that has seeped into the concrete can freeze. When water freezes, it expands by about nine percent. That expansion pushes against the surrounding concrete from the inside. If this happens repeatedly, the internal pressure can cause chunks of the surface to pop off, a condition called spalling. It can also widen existing cracks into larger gaps.

Freeze-thaw damage is most common in areas that experience many cycles of freezing and thawing. Even in warmer regions, a single hard freeze after a heavy rain can do damage. The key is to keep water from getting into the concrete in the first place. Sealing cracks and improving drainage can reduce the chance of water finding a way in.

Start by inspecting your concrete for existing cracks. Small hairline cracks can often be sealed with a concrete crack filler to prevent water from getting in. Larger cracks may need professional attention. If you notice a crack that is growing, or if the concrete is shifting, it is worth having a water damage inspection to understand the cause.

For significant water damage, you may need water extraction services to remove standing water from under or around the slab. Water damage cleanup can address the mess, and water damage repair services can handle the structural fixes. Acting quickly can stop a small crack from becoming a major problem.

Keep in mind that not all cracks are structural. Some are just cosmetic. But any crack that lets water in can lead to bigger issues. If you see signs of moisture inside your home, such as damp spots or musty odors, it is time to call in the pros. They can assess the situation and recommend the right steps.

• Seal small cracks as soon as you notice them
• Keep gutters clean and direct downspouts away from concrete
• Grade soil so water flows away from paved surfaces
• Avoid planting water-loving trees near concrete slabs
• Consider a water-repellent sealer on new concrete
• Check for standing water after a rain and fix the cause