What Is concrete sweating?
Concrete sweating, also known as Sweating Slab Syndrome, occurs when warm, humid air comes into contact with a cooler concrete surface, causing condensation to form. This is similar to how a cold beverage can develop moisture on its exterior on a warm day.
What Causes Concrete Sweating?
The primary cause of this phenomenon is the temperature difference between the air and the concrete surface. When warm, moist air encounters a cold concrete slab, it cools down, and if it reaches the dew point, condensation occurs, leading to the accumulation of water droplets on the concrete surface.
Sources Of Concrete Dampness:
- High Humidity: Failing ventilation in your space can cause humidity to excessively build up and force your concrete floor to sweat, even when your vapor barrier is functioning.
- Faulty or Missing Vapor Barrier: When the vapor barrier underneath your concrete floor isn’t working properly, moisture from the ground will seep up and bead on top of your floor.
How To Test For The Moisture Source?
In order to determine whether the moisture on your concrete floor is caused by humidity or a faulty vapor barrier, follow these steps:
- Tape a 2×2 ft square of plastic sheeting onto a dry area of the concrete surface.
- Leave the plastic sheeting in place for at least 48 hours.
- After 48 hours, remove the plastic and check for moisture condensation.
If you notice beaded moisture under the plastic sheet, it’s likely due to a faulty or missing vapor barrier. If there is no beaded moisture, the problem is probably related to high humidity in your space.
Potential Hazards of Concrete Sweating
Concrete sweating can lead to several issues, including:
Slippery Surfaces: The accumulation of water on concrete surfaces can create hazardous, slippery conditions, increasing the risk of falls and injuries.
Mold Growth: Persistent moisture on concrete can foster mold growth, which poses health risks due to the allergens and toxins produced by mold.
Alkali-Silica Reaction (ASR): This chemical reaction between alkalis in cement and reactive silica in aggregates can cause significant damage to concrete over time, including cracking and structural weaknesses.
Efflorescence: The movement of moisture through concrete can carry salts to the surface, leaving behind unsightly white deposits and potentially weakening the concrete.
Extensive Damage: Not only can excess moisture on or inside your concrete cause damage to the slab directly, but it can also damage the items on top of the concrete. When moisture is persistent on a slab, anything on top is subject to be damaged such as metal items like tools rusting or cardboard boxes getting damp and becoming soft.
How To Prevent It
Hydro-Block by Concrete Moisture Mitigation Inc. is a specialized penetrating concrete sealant designed to prevent concrete from sweating by creating a permanent, internal barrier against moisture. This product works by deeply penetrating the pores of the concrete, where it reacts with the free lime and alkali present, transforming these into a solid, unified mass. This reaction effectively seals the concrete, making it waterproof and preventing moisture from reaching the surface. The advanced formulation of Hydro-Block not only stops moisture from traveling through the concrete slab but also strengthens and densifies the concrete over time, reducing surface dusting and enhancing the overall durability of the slab. Additionally, the sealant includes antimicrobial properties that inhibit mold and mildew growth, making it an ideal solution for various environments, from residential spaces to large commercial and healthcare facilities.
Other Solutions To Try And Prevent Concrete Sweating:
Improved Ventilation: If the moisture source is not coming through the concrete and in the case of high humidity, improving ventilation and controlling the temperature should help resolve the problem.
Vapor Barriers: High-quality vapor barriers are designed to be installed beneath concrete slabs, effectively blocking moisture from the ground. If you have an existing slab then this solution is not a viable option.
Moisture Mitigation Coatings: There are specialized coatings applied to the surface of the concrete to create a protective layer that prevents moisture accumulation and ensures the concrete remains dry and safe. These coatings work as a membrane that goes on the surface of the concrete. These systems are subject to issues such as; trapping moisture below the membrane, ripping or tearing, delamination, and more.
Dehumidification Systems: Dehumidifiers are designed to efficiently reduce indoor humidity levels, creating an environment that minimizes the risk of concrete sweating. However, in the case the moisture is rising through the slab itself, dehumidifiers will not 100% solve the issue.
Identifying the source of moisture is crucial for effective solutions, which can vary based on the age of the concrete and budget considerations. However, for a guaranteed solution that ensures concrete surfaces remain dry, safe, and durable, thereby preventing issues associated with concrete sweating, Hydro-Block Penetrating Concrete Sealant (or equivalent products) is recommended in combination with improved ventilation. Our approach not only mitigates immediate symptoms but also addresses the underlying causes, providing a comprehensive and long-term resolution to this prevalent issue.