The Two Tiers of Testing

Every flooring professional carries a handheld moisture meter. But knowing which tool to use—and when—is what separates a professional installer from a liability risk.

1. Electrical Impedance Meters (Non-Destructive)

These are your “spot check” tools. They send an electrical signal into the top inch of the concrete to identify conductivity changes caused by moisture.

• Use Case: Initial surveying to find “hot spots” in a large slab.
• Limitation: They are influenced by aggregate type and metal reinforcement. Most importantly, they do not measure moisture deep in the slab where it matters most.

2. In-Situ Relative Humidity Probes (ASTM F2170)

This is the industry standard for decision-making. It involves drilling a hole and inserting a probe to measure the RH at 40% of the slab depth.

• Use Case: The final “Go/No-Go” decision for installing flooring.
• Why it Wins: It predicts what the moisture equilibrium will be after the floor is covered.

Conclusion

Use your handheld meter to map the room, but never sign off on an installation without the data from an in-situ probe. If you lack the certification or equipment, IFTI’s nationwide technicians are ready to deploy.