Concrete Slab Sweating Explained by Floorcare Specialists Atlanta

At certain times of year in the Southeastern United States, we witness concrete slab sweating.This occurs when there have been long cool periods (like an ice or snow event – or prolonged period of cold, dry air) ahead of a warming trend. When we experience such a warming trend, air temperatures and humidity rise.

The concrete slabs in non-air conditioned spaces take longer to warm up than the indoor air temperatures. Just like taking a cold drink out of a refrigerator on a hot summer day, the slab will sweat. This will continue to occur until the concrete has warmed up or humidity is brought under control.

If you have slab sweating, there are some things that you can do to combat it: In order of cost (low to high).

1. Clean your floors: A clean floor is a safer floor. Oils, tire marks,dust and debris, mixed with moisture often create a very, very hazardous environment. A clean floor is the first line of defense, and the least costly. Hire FloorCare Specialists to clean your floor!

2. Maintain your floors: Don’t just clean your floor once a year – when it gets slick – Keep it clean all year long. Clean your floors regularly, eliminate build-up of dirt and debris, make your building safer, cleaner and healthier. Hire FloorCare Specialists to maintain your floors!

3. Buy an Auto Scrubber from FloorCare Specialists! We can sell you an industrial auto scrubber sized specifically to your building. You can use the auto scrubber to keep your floor clean and properly maintained by your own staff. When your machine is delivered, we will train you how to use it. We can even schedule an on-site equipment demo at your location so that you can “Try it before youbuy it.”

4. Get air moving! Air movement can help keep you floors dry. You can use fans and / or heaters.

5. Install HVAC not the least expensive option, but an option

nonetheless. HVAC will keep the temperature in your space constant, control the humidity levels, and prevent sweating.

If you have a slab sweating issue, feel free to call 678-802-6020, inspection and consultation.

For more information on this topic, the following are excerpts from some industry technical data.

Concrete sweating occurs when moisture intermittently develops on the surface of an interior concrete slab. Sweating can increase the slipperiness of the concrete surface and pose a serious risk to the safety of workers and material transport operations. There have been known cases of loaded fork lifts being unable to stop and sliding off a loading docks! In many cases, inventory has been damaged or destroyed by sliding transport equipment.

Slab sweating is most often experienced in non-climate-controlled, large warehouses. In some parts of the country, schools have also experienced moisture developing on floor surfaces when HVAC systems are shut down during summer.

Moisture is the underlying cause of concrete slab sweating. There are a number of factors that alone or in combination lead to this occurring. The classic cause of moisture developing on an interior concrete slab surface is dew point condensation.

Warm, humid air enters the structure through open doorways, windows, and vents. As this air diffuses throughout the structure, it condenses on any surface that is at or below dew point temperature, which is often the floor surface.

Slab condensation events most often occur with a rapid increase in ambient temperature and relative humidity. When warm, humid air enters a structure, it takes far less time to change the interior air temperature than it does the temperature of the slab. With such a rapid change in conditions, the slab temperature can easily be found at or below dew point.

At dew point, moisture from the air will condense on any surface where it is not readily absorbed, including glass, steel, floor coverings, coatings or a tight, hard steel troweled or densified concrete surface.

The cleanliness of the slab is a contributing factor. A slab surface covered with black rubber tire marks or exhaust deposits will reduce surface permeability. As a slab surface becomes less permeable, not only will it become less absorptive to moisture from above, but if an effective vapor retarder is not in place beneath the slab, moisture levels within the concrete and near the slab surface will increase over time.

The first step is to establish good housekeeping practices that remove any type of deposits from the surface of the slab. Commercially available cleaning agents can be used in floor scrubbing and vacuuming machines.

The next step is to examine air movement within the building. Many big box facilities provide little air movement and may exhaust interior air through roof vents, creating negative pressure in the building. Negative pressure within a structure quickly allows exterior air and other conditions to enter the building when loading dock doors are open.

Large ceiling fans can help reduce or eliminate slab sweating by minimizing ceiling-to-floor temperature differentials and increasing the surface evaporation rate. In addition, commercial dehumidification units can alter the interior building environment to help reduce or eliminate slab sweating. For facilities where inventory will be stored directly on the slab, a low- permeance, below-slab vapor retarder can help reduce the potential for moisture to migrate upward and condense beneath stored product.

Call for Quote 678-802-6020

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