The most effective way to avoid concrete slab moisture and pH-related flooring problems is to specify proper moisture testing on every project.

Unfortunately, on many projects, product manufacturer requirements are considered unnecessary, too expensive, or just plain ignored, but this often ends up becoming a much larger headache, down the road.

In fact, widespread instances of concrete slab moisture-related floor covering failures have emphasized the importance of accurate and complete moisture testing prior to the floor being installed. It is reported that over $1 billion dollars is spent every year to replace, repair and correct floor covering problems related to excessive moisture and elevated pH levels of concrete floor slabs.

Proper testing prior to installing a new floor or replacing an existing floor is the only way of knowing the moisture condition of the concrete rather than guessing what it might be. You can’t see, smell or feel moisture within, or emitting from a concrete slab, so the only way to really know is quantitative testing. Having these measurable results available enables better product decision-making at the time of installation, reduces the risk of a failure, and ensures you won’t lose a warranty claim due to moisture-related issues.

When should you test? Always. Test it if it’s old or new concrete—even if the existing flooring material appears to be in good shape. There are simply too many variables when installing new flooring to be sure it will perform at the same level.

The industry standard, ASTM F 710 – Standard Practice for Preparing Concrete Floors to Receive Resilient Flooring, puts it quite simply, and all floor covering and adhesive manufacturers agree: “All concrete slabs shall be tested for moisture regardless of age or grade level.” On-grade, above-grade, below-grade—from the penthouse to the basement—if it’s a concrete slab, test it.

How do you test? There are two quantitative methods widely recognized in the industry, and they are referenced in ASTM F 710: ASTM F 2170, Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using In-Situ Probes, measures moisture inside a concrete slab; ASTM F 1869, Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride, measures vapor emission at the concrete surface.

Both testing methods provide valuable information and it’s a good idea to perform both of them in addition to the pH test. Usually these three tests are done at the same time, and the data collected will provide a relevant understanding of the existing concrete slab’s moisture condition.

The importance of proper specifications cannot be over-emphasized. The volunteers from the floor covering and concrete industries who have worked together to create the ASTM documents mentioned above have done a great service to all in the floor covering community by creating industry standards. These documents, created through a consensus process, are thebook on how things need to be done.

In addition, floor covering and adhesive manufacturers have created published guidelines that follow these standards, often quoting them directly. Failure to follow manufacturer’s guidelines usually voids the warranty and in the event of flooring problems, a great deal of finger pointing can occur, which does not solve the problem and can create ill will among the parties involved.

Who Should Do the Testing?

There is much concern about whose responsibility it is to test the floor. The Floor Covering Industry White Paper Position Statement on Moisture Emission Testing, which was published by the World Floor Covering Association (WFCA), recommends independent third-party testing rather than assuming the contractor or the landlord/developer will do the right thing and test the floor.

Increasingly, commercial building owners and tenants are taking charge of the situation and mandating independent third-party testing of the floors in their buildings. This ensures the testing will be done correctly and there will be no conflicts of interest when the results are reported.

The best way for the owner or tenant to assure comprehensive moisture testing gets done is to write the testing specification themselves. A simple statement such as “install floor covering according to manufacturer’s instructions” is not enough.

What is needed is to create a specification section regarding moisture testing that will leave no question about what testing is to be done, when the floor will be tested, who is to do the testing, how the results are to be reported and who will receive a copy of the test report.

Depending on the circumstances, an analysis of the test results may also be commissioned. This would require the testing agency’s consultants to compare the test results with the requirements of the floor covering and adhesive manufacturer and make an assessment as to the suitability of the concrete slab for the particular floor covering product to be installed. If the concrete is not in compliance, corrective measures may need to be taken prior to the flooring installation.

How a moisture testing specification is written and used may vary, depending on the type of project. For example, in new construction or tenant improvement projects, a section on moisture testing can be inserted into the specification as a standalone document or as part of the floor covering specification. The language gives a landlord/developer or a general contractor clear direction on what you require of them to reduce the risk of concrete slab moisture related flooring problems.

In the case of renovation or flooring replacement projects where the owner is directly controlling the scope of work, the document may be more of an internal guideline. The guideline should comprise a step-by-step commonsense approach for determining the scope of concrete slab moisture testing, a statistical approach for assessing risk, and a cost-effective method for selecting a topical moisture control system.

In either case, it is important to specify who is responsible for testing and who is responsible for conducting the test. Specifying an independent third-party testing agency—someone whose only interest is collecting and reporting accurate and complete testing information—should be the preferred method, as opposed to requiring the floor covering contractor or the general contractor—who typically have a vested interest in the results—to carry out the testing.

Elements of a Specification

The elements of a moisture testing specifications should include the following six items:

•Type of testing to be done. Usually ASTM F 1869 and ASTM F 2170 moisture tests and pH testing per ASTM F 710.

•Number of tests. The standard calls for three tests for the first 1,000 square feet and one test for each 1,000 square feet thereafter, but the owner may change the number of tests based on their needs.

•Timing of testing. The temperature and humidity conditions are important and, on new construction, testing should be done after the building is enclosed and the HVAC system is up and running. For a renovation project, the testing should be done at least a month prior to the scheduled floor covering installation, so there is adequate time for corrective measures to be taken if they are necessary.

•Reporting. Test reports should contain as much information as possible about the conditions at the time of testing, methodology of testing and test results. This is an important way of documenting not only the test results but the accuracy of the testing that was done. A simple list of test results alone is not acceptable. The specification should also identify who is to receive the report—the owner, general contractor, flooring contractor, architect or all parties.

•Mapping. The more sophisticated reporting done by some independent agencies will show the test results on a map of the facility, which can help the construction team identify problem areas in the floor.

•Repair options. If appropriate, the report may include options for repairing a floor that exceeds the flooring/adhesive manufacturer’s recommended limits. The section may list moisture vapor control treatments, adhesives or other means of correcting the condition and allowing the floor to be installed.

ASTM F 710 covers many of these points and is an important document every owner should have in their specification libraries.

Moisture-related flooring failure continues to cost building owners and tenants a great deal of money and lost time. It pays for these parties to take charge of the process, requiring testing by independent third-party agencies and creating detailed specifications that direct the entire construction team as to what is expected of them so potential flooring problems can be identified and solved in advance. 

Lee Eliseian is the president, CEO and principal consultant of Independent Floor Testing and Inspection (IFTI). He has over 30 years of experience in the flooring industry, specializing in national independent third-party concrete slab moisture testing, floor covering failure analysis and moisture mitigation systems. He is an active member of the ASTM F06 Committee on Resilient Flooring. He chairs the ICRI 710-B Subcommittee on Moisture-Related Issues with Concrete Floor Finishes and is an active member of the ACI 302.2R Committee on the Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials. To contact him, call (800) 490-3657 or lee.elseian@ifti.com.