The chances of bond-failure can be greatly minimized by conducting proper moisture testing prior to flooring installation. The majority of the flooring industry recognizes a calcium chloride test or relative humidity test as measuring concrete moisture prior to installation. Including these tests in flooring specifications will reduce your exposure to liability.
The following outlines the problem, the test procedure, and cite the limitations on moisture by a number of organizations responsible for specifications.
Moisture has been causing floor covering problems since the beginning of time. Many new floor coverings stop or slow the transmission of moisture moving upward through the slab. Water vapor conditions can exist for years without causing problems in places where the slab has never been covered with a floor that allowed moisture to pass through. If you install a new floor that traps moisture, there’s trouble ahead!”
Moisture related failures of resilient floor coverings installed over concrete have focused unfairly on the premise that the product itself is at fault or the flooring contractor, perhaps, did not install the product correctly. Moisture and alkali can cause the following problems AFTER installation:
1. Adhesive deterioration.
2. Bumps, ridges, or bubbles.
3. Color changes.
4. Mold, mildew, or bacteria growth.
5. Efflorescense (alkali build-up at tile joints).
6. Tile peaking or curling.
Any of these conditions could occur at any time after installation if a moisture condition is present.
The Resilient Floor Covering Institute “All concrete subfloors on and below grade should be tested for moisture…A dusty concrete floor on or below grade can be a sign of alkali salts, and a moisture test should be run. The alkaline salts in solution with moisture, which exude from drying cement or which work their way up from the earth in concrete on and below grade, have, in addi-tion to deteriorating effects, a tendency to prevent or destroy satisfactory bonding of adhesives by sheer physical displacement or to leave unsightly salt deposits at the seams of sheet materials and joints of tiles. Excessive amounts of ground moisture can, of course, create problems for on- and below grade areas of commercial and residential buildings over and beyond those relating to the installation and use of resilient flooring.”
“The Resilient Floor Covering Institute subscribes to the use of the Rubber Manufacturers Asso-ciation moisture test method. It has been widely used and accepted by the flooring industry since the early 1950’s and quantitatively measures the rate of moisture transmission through a concrete slab.”

The Rubber Manufacturers Association “…the moisture specification shall be that the emission of moisture vapor from the (concrete) floor shall not be more than 3.0 pounds per 1,000 square feet per 24 hours…If a concrete underfloor, tested with this unit in accordance with directions, meets the stated conditions and specifications, rubber and solid vinyl flooring may be installed satisfactorily…”
Western Floor Covering Institute “The West-ern Floor Covering Institute cites in their guide-lines a number of testing methodologies and specifically cites the Rubber Manufacturers As-sociation test and limitation for any flooring in-stallation at 3.0 pounds per 1,000 square feet per 24 hours using a calcium chloride test.”
The Carpet and Rug Institute “In order to pre-vent glue-down installation failures due to mois-ture and alkalinity, the owner or general contrac-tor shall be responsible for providing written moisture and alkali test results pertaining to the concrete floor slab prior to installation. Concrete floors, even with adequate cure time, can dem-onstrate an unacceptable moisture condition by allowing excessive amounts of moisture to pass through. This can be a problem even for sus-pended concrete floors. Therefore, all concrete floors should be tested to determine the moisture emission rate by utilizing a calcium chloride moisture test kit…This is a very precise test…As a general guideline, an emission rate of 3 lbs. or less is acceptable for most carpet. In the range from 3 to 5 lbs., carpet with backing of porous constructions can usually be installed success-fully; however, the risk of failure increases. An emission rates above 5 lbs. is generally consid-ered unacceptable.”
In Summary
The flooring manufacturers did not create the problem of moisture vapor emission. It is a natu-ral constituent of all hardened concrete. How-ever, by setting limitations as to HOW MUCH vapor emission is tolerable, they are helping to reduce the potential for failure which has proven to be extremely costly to everyone.
The majority of flooring material manufacturers, in order to help architects, contractors, flooring contractors, and building owners understand the problem of moisture, have adopted the calcium chloride test and the relative humidity probe tests as the primary measurements of moisture vapor emissions since and provides useful information for making decisions.
Flooring material manufacturers simply do not warrant against bond failures due to moisture. The limit of 5.0 pounds is not necessarily their limit of liability, but a limit as to whether or not flooring should ever be installed.
The bottom line is that by specifying quantitative limits for moisture, everyone involved with the flooring specification and installation has the op-portunity to avoid a costly moisture related fail-ure. By NOT setting quantitative limits, it be-comes a subjective gamble as to whether or not the substrate is safe for installation.
The responsibility, therefore, to determine mois-ture levels for any flooring installation lies with the architect, contractor, flooring contractor, and building owner, as well as the liability involved if the flooring bond fails.

Facts Everyone Should Know About Flooring Installations Over Concrete
1. All concrete regardless of age or grade-level emits some degree of moisture and must be tested prior to installation.
2. The majority of flooring material manufacturers, organizations, and experts recognize the Rub-ber Manufacturer’s Association Test (calcium chloride) as their primary criterion for determining moisture vapor emission limitations since it is the only quantitative measurement of moisture.
3. Mat and bond tests do not model vapor emissions and are only subjective, at best, in their in-terpretation.
4. The calcium chloride test is inexpensive (about $12.00) and used by the vast majority of floor-ing contractors.
5. Flooring manufacturers do not warrant against substrate moisture, and most recognize a limit of 3.0 pounds as the maximum allowable amount of moisture vapor emission. Pounds refers to the actual weight of the water passing through a 1,000 square foot surface area, every 24 hours.
6. Calcium chloride crystal tests produce their results by changes in weight. The dish must be weighed within 1 hour after upon termination of the test to be valid. Mailing off the dish to be weighed invalidates the results.

Special Thanks To JJ Haines for the info