Concrete RH Testing Best Practices, Part 2
Whether you’re a small, medium, or large-scale flooring professional, working on a residential flooring project or commercial flooring project, the fundamentals for success stay the same: be prepared, work with the right tools, work safely, and, most importantly, communicate.
So you’ve got the job. It is precisely at this point where breakdowns can occur that can cost more than dollars – your credibility and reputation.
Good, constant, and productive communication with the general contractor, architect, project manager, site owner, dealer, or even end-user is vital to the process, and largely overlooked. If you’re reading this and debating whether your current level of communication is adequate, then the goal of this paragraph is fulfilled.
Take the extra steps to initiate and maintain good lines of communication. It is imperative that everyone involved knows what is being commissioned of the testing technician and the scope of the work that is being proposed.
Conduct interviews to verify exactly what jobsite conditions exist prior to testing. This is often where significant discoveries are made that will prove valuable to the reliability of the test results, not to mention the safety of the testing technicians.
Interviews before the testing process will be helpful for you to determine the age of the structure, slab pour date and depth, suspended slab details, vapor retarder details, buried metals or fiber-optics, and more. For example, ASTM F2170 in situ concrete slab moisture testing over suspended corrugated pan decking requires different procedures than testing on grade or below grade. A precast, post-tensioned substrate that has been capped with a 1” to 2” leveling pour will require yet another set of skills.
Remember that “preparation eliminates pressure” and maintaining good communication throughout the project is a great way to help ensure your preparedness and that your weekend pool party isn’t ruined by angry calls from customers.
The F2170 In Situ Probe Test for Concrete Slab Relative Humidity
Since this article series references the ASTM F2170 standard regarding concrete moisture testing, let’s cover the salient points of the test process. If you utilize the F2170 testing procedure, this will be a good refresher.
If you are thinking of employing the F2170 standard as your procedure to test for relative humidity (RH) in concrete slabs, consider this an introduction, but be aware that it is not meant to supersede any information found within the ASTM F2170 standard. To download the ASTM F2170 standard for testing concrete moisture with in situ relative humidity probes, visit https://www.astm.org/Standards/F2170.htm.
The correct hole depth and hole diameter are important in complying with the ASTM F2170 standard. Drill a hole in the concrete slab to the required depth using a rotary hammer drill and a masonry drill bit diameter appropriate for the manufacturer’s sleeve being used. For fast drilling and cleanup in one easy step, you will want to use a high-quality drill bit that is long-lasting and gives you a 100 percent clean concrete hole before placing your test sensors. But if you lack a drill bit with vacuum capability, there are vacuum attachments available that you can attach to the straight extension of a shop vacuum cleaner hose.
The correct diameter and hole uniformity are absolutely essential to the test procedure. Consult the manufacturer’s specifications of hole diameter for the in situ RH testing system you are using. Following the F2170 standard, ensure that the hole is no more than .04″ (1mm) larger in diameter than the sensor probe. Avoiding this step may cause damage to the sensor probe when attempting insertion. If you are testing in thicker slabs, ensure that you have the proper number of extensions to conform to ASTM F2170. Once you have obtained RH readings, you’ll need to evaluate the slab’s readiness for the flooring installation. Consult the respective manufacturer’s installation guides and their specific RH thresholds.
Record, rinse, repeat
Always maintain accurate record keeping of obtained results. This is a legal essential no one should ignore. You must be able to produce either date-stamped photographic evidence or digitally recorded measurements proving a valid test result. The best testing procedures are no better than the ability to prove an obtained test result of that procedure.
Once the results are delivered, it’s important to be available to discuss findings and to make sure every involved stakeholder understands what the measurable data means.
Jason Spangler, Wagner Meters’ flooring division manager, has more than 25 years’ experience in sales and sales management across a broad spectrum of industries. Jason, who received an MBA from West Texas A&M University in November 2018, has extensive industry involvement, including the National Wood Flooring Association (NWFA) and the International Certified Flooring Installers Association (CFI), and is Vice Chairman of Associations for the Flooring Contractors Association (FCICA). He can be reached at 800.207.2478 or firstname.lastname@example.org. Learn more at wagnermeters.com.