Pro -

1. Results of calcium chloride tests are accepted by most manufacturers of floor covering, adhesive and resinous coatings for concrete dryness and suitability for the installation of their products. ASTM F 710 contains the statement that concrete can be considered suitably dry when tested in accordance with test method ASTM F 1869-04.

2. Testing is relatively easy to perform, no major investment in equipment is required.

Con -

1. The subject building must be acclimated at or near the temperature and relative humidity levels anticipated during occupancy or use. This is often a difficult requirement to meet on a new construction project. If the HVAC system is not operational at the time of testing a significant variance between the test environment and intended use environment will cause test data to be questioned.

2. Calcium chloride tests reflect moisture vapor emission from the surface of the concrete. The test reflects moisture in the top 1/4 to 1/2 inch of the slab's thickness. If ambient environmental conditions vari immediately preceding testing, the concrete surface may be affected and test results may be skewed.

3. Testing on an open, or breathing, concrete surface may not reflect moisture deep within or directly below the concrete slab. Once covered by floor coverings, concrete moisture content will equalize within the thickness of the slab. This may mean that a greater volume of moisture will be present at the floor covering to concrete interface than was originally anticipated.

4. "Home-made" calcium chloride test kits are being used. These kits do not meet the apparatus requirements of ASTM F 1869-04 and are delivering questionable results.

5. Too many tests are being set without floor preparation as required by ASTM F1869. Surface contaminants and residue can reduce vapor emission at the test site and produce inaccurate test results.