Warehouses and sweating slab
By Megan Browning

Condensation occurs when warm, moist air contacts a cold surface. As the air becomes colder, it loses its ability to store moisture. In the summer, this process can be seen as a sheen of water droplets on cans and bottles containing cold beverages. But in the spring and fall, temperature swings and the accompanying condensation can wreak havoc in workplaces of many types — especially warehouses. The accumulation of those little droplets of water can be a big problem.

Let’s take a look at the issues this slippery situation can create, and some potential solutions.

Does your facility have a problem with sweating slab?
  • 1. Yes
  • 2. No

Safety concerns and product integrity issues

Sweating slab isn’t just annoying – it creates a potentially hazardous environment for employees on foot, as well as those operating mechanical equipment.

Research shows why this is a grave area of concern for warehouse owners and managers. According to the National Floor Safety Institute, the majority of workers' compensation claims are attributed to employees falling on slick floors1, and these accidents are also the leading cause of occupational injury for people aged 15-24 years. Falls account for over 8 million hospital emergency room visits, representing the leading cause of visits (21.3 percent). Rectifying such issues help businesses operate more efficiently and effectively, in addition to avoiding costly claims.

Condensation also creates product integrity issues when cold materials, such as metal, are brought into a warmer space. It may take hours, or even days, for the temperature of the delivered product to approach the inside air temperature. During this warm-up period, the item’s surface temperature is initially below the dew point temperature of the air, leading to condensation on the surface. Besides moisture being a slippery situation, it can also lead to corroded metal, damp packaging and paper, mold and a host of other downright gross issues.

Solving sweating slab

Though you can’t control nature’s seasonal fluctuations, there are solutions to prevent sweating slab from compromising product integrity and employee safety. Air conditioning can lower the moisture content of air and heating systems can increase surface temperature, and both of these tactics decrease the amount of time that warm air is in contact with cold surfaces. However, these tactics are often impractical and expensive in warehouse environments. Instead, introducing gentle air movement is a simple and affordable solution.

Increased air circulation reduces concrete sweat by moving stagnant air off the cold surface before it has a chance to cool down enough to leave telltale puddles behind. Thoroughly mixing the air within the space will also help to raise the slab temperature more quickly, shortening the season for condensation.

Case in point

Any change in humidity or weather caused the concrete floor to sweat at Charlotte, N.C., HVAC equipment distributor N.B. Handy. This created a standing puddle that was referred to as “Lake Handy.”

“The forklifts were unsafe to drive because they couldn’t stop, and people would slip on the water,” said N.B. Handy Operations Manager Blake Boleman. “We had one forklift go through the wall in our sales room—luckily, no one was hurt. The products would get water on them too.”

Ultimately, N.B. Handy incorporated air movement by installing six large diameter, low speed fans and said goodbye to their watery woes. After this addition, “Lake Handy” experienced a record drought, drying up completely and creating safer working conditions.


While sweating slab can be a nuisance to managers and employees, the simple addition of air movement resolves the issue easily. Incorporating air movement throughout a warehouse can mitigate condensation issues while also improving worker comfort year round, reducing heating costs in the winter and improving indoor air quality.

Megan Browning is a writer for Big Ass Fans, a designer and manufacturer of large diameter, low speed fans.