Concrete Drying

Flooring failures attributed to moisture-related concrete problems are at near epidemic proportions today. Coatings, carpet, vinyl, rubber, wood, laminates and most floor coverings are affected to one degree or another by pH issues and excess water vapor emissions through a concrete slab. Moisture causes gaps between tiles, adhesive oozing, bumps, dents, cupping, bubbles, indentations, wheel marks and more. Left uncorrected, these problems can evolve into health and safety issues caused by mold, mildew and floors lifting. Concrete drying is an effective way to battle these issues.

Cement vs. Concrete, Curing vs. Drying

When contemplating concrete drying it is important to understand some of the commonly misused terminology:

• Cement - the grey powder ingredient in concrete, not the finished product
• Concrete - cement powder, water, sand, and aggregate (rocks) bonded together
• Concrete curing - the chemical reaction that bonds the ingredients together to form concrete
• Concrete drying - the process of evaporating the excess water from cured concrete

The Concrete is Cured, When Can the Floor Be Installed?

To say “It looks dry,” “It feels dry,” or “It seems dry,” isn’t enough. Taping a plastic sheet to the floor for a day or two also has been proven to be an inaccurate indicator. The easy-to-use electronic meters that test for moisture in concrete yield only a spot test that isn’t a good basis for a go or no-go decision for a flooring installation.

The drying time before slabs are ready for moisture testing depends on atmospheric conditions and mix design, according to F 710. A 4-in. thick slab allowed to dry from only one side typically requires 90 days to 120 days to achieve a moisture vapor emission rate (MVER) of 3 lb. water/1,000 sq. ft. per 24 hr (the resilient flooring industry standard MVER). Suspended slabs -– the second floor and above -- often contain a lot more water, and take even longer to dry. As noted in ASTM F 710, lightweight concrete, floors containing lightweight aggregate or excess water, and those that dry from only one side, such as concrete on metal deck construction, may need a much longer drying time. One laboratory study found that at ideal conditions (70°F, 50% relative humidity) it took 46 days for a standard mix to dry and 168 days for a lightweight mix. Those were both under ideal conditions – concrete with the right amount of water at the perfect temperature and humidity. In the real world it takes even longer.

Concrete drying time is significantly shortened with Mobile Air’s concrete drying rental.

Placed correctly, concrete floors can accept any floor covering to provide a long-lasting and durable wearing surface in almost any type of space. However, because of the fast-track nature of a lot of today’s construction projects, the installation often is rushed and failures occur. So, it’s important to know what to ask for, how to test, and what to do if you discover a problem.

Mobile Air, Inc. can help you with your concrete drying needs. Using our years of Construction Based Indoor Climate Controls, Mobile Air, has developed methods to effectively dry concrete in a cost effective manner. We are ready to help you to solve your concrete drying situation.

To learn more about concrete drying from Mobile Air call us at (888) 474-4340.