The Essential Steps for Conducting a Moisture Test on Concrete Floors

The Essential Steps for Conducting a Moisture Test on Concrete Floors

Conducting a moisture test on concrete floors is crucial, especially before installing sensitive flooring materials such as wood or certain types of tiles. Excessive moisture can lead to various issues like mold growth, flooring damage, and adhesive failure. Here are the essential steps for conducting a moisture test on concrete floors:

Gather Necessary Tools and Equipment:

  • Moisture testing kit (such as a moisture meter or calcium chloride test kit)
  • Plastic sheet or moisture vapor emission rate (MVER) testing equipment
  • Adhesive tape
  • Penetrating sealer (if using a calcium chloride test kit)
  • Plastic dome or cover for MVER testing (if applicable)

Prepare the Concrete Surface:

  • Ensure the concrete floor has cured for at least 60 days (for new constructions) or according to the manufacturer’s recommendations.
  • Clean the surface of the concrete floor to remove any debris, dust, or contaminants.

Choose the Right Test Method:

  • There are several methods for moisture testing, including the calcium chloride test (ASTM F1869) and the relative humidity test (ASTM F2170). Consult with flooring manufacturers to determine the most appropriate method for your specific flooring material.

Perform the Moisture Test:

  • Calcium Chloride Test:
    1. Place a pre-weighed dish of calcium chloride on the concrete surface.
    2. Seal the dish with adhesive tape and leave it for the specified time (usually 60-72 hours) as per the manufacturer’s instructions.
    3. Weigh the dish again to determine the weight gain, which indicates the amount of moisture absorbed by the calcium chloride. This is measured in pounds of moisture per 1,000 square feet per 24 hours (lbs/1000 sq. ft./24 hours).
  • Relative Humidity Test (In-situ Probe Test):
    1. Drill a hole into the concrete floor at the specified depth according to the flooring manufacturer’s guidelines.
    2. Insert the relative humidity probe into the hole.
    3. Seal the hole with a moisture-resistant material.
    4. Leave the probe in place for the specified time to equilibrate with the concrete’s moisture content.
    5. Measure the relative humidity using a handheld meter or data logger.

Interpret the Results:

  • Compare the moisture measurement results with the recommended levels provided by the flooring manufacturer. Different flooring materials have different moisture tolerance levels.

Take Necessary Precautions:

  • If moisture levels are above the recommended limits, take necessary precautions such as installing a moisture mitigation system, using moisture-resistant adhesives, or choosing a different flooring material.

Document the Test Results:

  • Keep a detailed record of the moisture test results, including the testing method used, measurements taken, and any actions taken to mitigate moisture issues. This documentation is essential for warranty purposes and future reference.

Consult with Professionals:

  • If you are unsure about conducting the moisture test or interpreting the results, consult with flooring professionals or experts who can provide guidance based on their expertise and experience.

Remember that moisture conditions in concrete can change over time due to various factors such as weather conditions and site location. Regular testing and monitoring are essential, especially in environments where moisture levels fluctuate frequently.

The Top Maintenance Strategies to Conduct a Moisture Test on Concrete Floors

Conducting regular moisture tests on concrete floors is essential for maintaining the integrity of the flooring and preventing issues related to excess moisture. Here are the top maintenance strategies to consider when conducting moisture tests on concrete floors:

Regular Monitoring:

  • Establish a regular schedule for moisture testing, especially in areas where moisture levels can fluctuate, such as basements or areas prone to water exposure.

Follow Manufacturer Guidelines:

  • Adhere to the guidelines provided by flooring manufacturers regarding acceptable moisture levels for their products. Different flooring materials have varying tolerance levels to moisture.

Use Reliable Testing Methods:

  • Employ reliable and accurate testing methods such as calcium chloride tests or relative humidity tests. Ensure that the testing equipment is properly calibrated for accurate results.

Consider Environmental Factors:

  • Be mindful of environmental factors such as humidity, temperature, and weather conditions. These factors can influence the moisture levels in concrete. Consider these factors when planning the timing of your moisture tests.

Pre-Installation Testing:

  • Conduct moisture tests before installing any flooring material. This step is crucial to prevent issues like warping, mold growth, and adhesive failure. Address any moisture problems before the flooring installation.

Post-Installation Testing:

  • Even after flooring installation, continue to monitor moisture levels periodically. Changes in the environment or potential water leaks can affect moisture conditions over time.

Implement Moisture Mitigation:

  • If moisture levels exceed the recommended limits, implement moisture mitigation measures. This could include applying sealers, installing vapor barriers, or using moisture-resistant adhesives.

Proper Site Preparation:

  • During construction, ensure proper site preparation, including adequate drainage systems and vapor barriers beneath the concrete slab. Proper site preparation can prevent moisture issues in the long run.

Regular Inspections:

  • Conduct regular visual inspections of the concrete floor. Look for signs of water damage, such as discoloration, efflorescence, or mold growth. Early detection can prevent extensive damage.

Educate Personnel:

  • Educate maintenance staff and other personnel about the importance of moisture control. Make sure they understand the signs of moisture-related issues and the necessary steps to take if a problem is detected.

Documentation and Record-Keeping:

  • Maintain detailed records of all moisture tests, including dates, methods used, measurements taken, and any corrective actions implemented. This documentation is valuable for future reference and warranty claims.

Consult Professionals:

  • If you are unsure about conducting moisture tests or interpreting the results, consult with professionals or experts in the field. They can provide specialized knowledge and guidance tailored to your specific situation.

By following these maintenance strategies and staying proactive in monitoring and addressing moisture issues, you can significantly prolong the life of concrete floors and prevent costly repairs or replacements in the future.


In conclusion, conducting moisture tests on concrete floors is a vital aspect of building maintenance and construction. It ensures the longevity and durability of flooring materials while preventing potential issues related to excess moisture, such as mold growth, warping, and adhesive failure. By following the essential steps outlined, including regular monitoring, using reliable testing methods, considering environmental factors, and implementing proper moisture mitigation measures, property owners and professionals can maintain concrete floors effectively.

Additionally, adhering to manufacturer guidelines, conducting pre-installation and post-installation tests, and educating personnel about moisture control contribute to a comprehensive moisture management strategy. Proper site preparation and regular inspections, coupled with detailed documentation of tests and actions taken, further enhance the overall maintenance approach.