Looking for information about efflorescence on concrete? If so, don’t hit that back button because you’ve landed on the right page. In this article, we’ll review efflorescence, what causes it, how to get rid of it, and how to prevent it.
What Is Efflorescence?
Efflorescence refers to the formation of water-soluble salts on the surface of porous materials. It’s a phenomenon that occurs when soluble minerals or salts within building materials – such as concrete, brick, or mortar – are brought to the surface by moisture, creating a crystalline deposit that appears as a white powdery substance. Efflorescence is a common problem in buildings that are exposed to water.
The efflorescence process occurs when water carrying soluble salts is transported through the concrete foundation wall via capillary action or water vapor diffusion. When the water evaporates at the material’s surface, the salts are left behind, forming a crystalline deposit. The most common salts in efflorescence are calcium carbonate, calcium sulfate, and sodium sulfate.
Efflorescence can damage building materials over time. The crystalline deposits can cause the material to expand, leading to cracking, flaking, and deterioration. It can also be unsightly, detracting from the appearance of buildings and structures.
Primary vs. secondary efflorescence
Primary efflorescence occurs when concrete bleed water rises to the surface and evaporates, leaving behind salts that crystallize on the surface. Primary efflorescence usually occurs within the first few days of the concrete being poured.
Secondary efflorescence occurs after the concrete has cured. It’s caused by moisture entering the concrete foundation wall from somewhere else. For example, water penetration through the foundation wall because of poor drainage. The moisture moves through the material and evaporates on the surface, leaving salts behind. Secondary efflorescence can occur at any time after the material has cured.
Efflorescence is not a structural problem
Efflorescence is not a structural problem and does not affect the strength or durability of the concrete foundation wall. However, it can be unsightly and may require cleaning or removal. Additionally, if efflorescence results from water penetration through the foundation wall caused by poor drainage, it may indicate a more serious problem that needs to be addressed to prevent further damage to the foundation.
What Causes Efflorescence On Concrete?
Water causes efflorescence. Specifically, efflorescence occurs when water infiltrates the concrete and evaporates on the surface, leaving salts behind.
The presence of efflorescence on a concrete foundation wall is often a sign of excess moisture in the ground around the foundation, as water is required for its formation. The problem is poor drainage, in other words. If not addressed promptly, poor drainage around a foundation can lead to serious foundation problems.
Can Efflorescence on Concrete Be Removed?
Fortunately, there are various methods to remove efflorescence from concrete surfaces. These include the following:
- Use an efflorescence remover – This is a specially formulated solution that dissolves the salts and removes them from the surface of the concrete. These solutions are typically applied by spraying or brushing onto the affected area and can be rinsed off with water after a short period of time.
- Pressure washing – You may be able to remove efflorescence via pressurized water. Be sure to dry the concrete after you’re done, though.
- Scrubbing with a stiff brush – You can also try to brush the efflorescence off using a stiff brush.
How To Prevent Efflorescence
The best way to prevent efflorescence from forming on your concrete foundation walls is to make sure there’s no excess moisture either penetrating through the foundation wall or coming into contact with it. Here are some ways to do that:
- Ensure good drainage around the foundation – Proper drainage around the foundation will ensure excess moisture in the ground doesn’t cause hydrostatic pressure to build up and push against the concrete foundation wall. Hydrostatic pressure can push moisture through cracks in a foundation wall you didn’t even know existed. Installing a drain tile system is an excellent way to prevent excess moisture from building in the soil.
- Regrade your yard, if necessary – Regrading ensures that water flows away from the foundation, preventing any buildup of moisture that may cause foundation issues.
- Install downspout extensions – Downspout extensions are inexpensive and easy to install. They will ensure that runoff gets carried away from the foundation before release.
- Clean gutters regularly – Clean gutters regularly to prevent dead leaves and other debris from accumulating, clogging the gutters, and causing water to spill over the side of the house and soak the ground around the foundation.
- Keep water-hungry vegetation away from the foundation – Flowers and shrubs might look beautiful next to the house. However, if they need a lot of water, you’ll be adding water to the ground around the foundation. This is precisely what you’re trying to avoid.
- Close basement windows or crawl space vents – Open windows or vents allow warm, humid air to enter and condense on cooler surfaces.
- Check for plumbing leaks – These are another source of moisture.
If you’re concerned about efflorescence on your concrete foundation wall, contact us today to schedule an evaluation. If we find a problem, we’ll give you a repair estimate.
