Relative Humidity Testing for Concrete Floors

Ron Smith, Product Application Specialist at Wagner Meters, introduces our main speaker and outlines this webinar. Moisture is always an issue in concrete slabs.

2009 Copyrighted material by Wagner Meters All rights reserved. www.rapidrh.com

Relative Humidity Testing for Concrete Floors

Introduction by Howard Kanare, Senior Principal Scientist at CTLGroup, a subsidiary of Portland Cement Association. As a result of over 20 years of field experience, and seeing the issues addressed in these segments, Kanare developed a stay-in-place relative humidity probe to mitigate all these issues. Kanare starts out by discussing how moisture is always an issue in concrete slabs.
2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Moisture is Always an Issue in Concrete Slabs

Finding the true moisture condition in slab is important and Howard will discuss the different considerations that must be taken into account. Relative humidity, measured in the middle of the floor system not only is the best predictor of floor covering and adhesive system performance.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Calcium Chloride Shown to Give False Readings Part I
Calcium chloride testing has never had a strong scientific basis. It has bee shown to provide both false positive and false negative results. Kanare will discuss the history of CaCl₂ testing and the flaws of this test method.

2009 Copyrighted material by CTLGroup.
All rights reserved. Used with permission by Wagner Meters

Calcium Chloride Shown to Give False Readings Part II
Extensive testing has shown that calcium chloride testing is very unreliable. Additionally, there is no strong correlation between calcium chloride test results and in situ relative humidity test results. Kanare sums up the problems with the ASTM F1869 calcium chloride test method.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Problems with Moisture Meters

At best, handheld concrete moisture meters are designed to be used as a survey tools. Since they cannot measure much more than .75-inch below the surface, and can be affected by other variables in the concrete, these meters cannot give an accurate picture of the moisture condition deeper in the slab.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Problems With the Hood Method

Initially adopted in Europe, the hood method for testing surface relative humidity was recently accepted in the USA. Its sensitivity to varying concrete conditions and amount of time needed to yield accurate results make this method impractical in many ways.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Relative Humidity the Most Useful Test Method?

Kanare will show why measuring the relative humidity at the correct slab depth will reveal a true picture of the future moisture condition of the slab’s surface after a floor covering has been installed.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Rapid RH - Most Accurate Measurement Device

Smith discusses why depth-specific measurement is crucial, and why the Rapid RH is the best method to obtain depth-specific relative humidity readings.

2009 Copyrighted material by Wagner Meters All rights reserved. www.rapidrh.com

Relative Humidity: the Fastest Method

By using the most accurate and proven testing method, there is no need to use any other test method, such as calcium chloride.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Relative Humidity Provides Results Faster Than Any Other Method

RH probes can give us an accurate answer in a relatively short amount of time. Although ASTM still requires 72 hours, decisions can be made much sooner.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Leapfrogging Problems with Reusable Probes

Kanare demonstrates how reusable probes must re-equilibrate when moved from hole-to-hole.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

The Rapid RH Solves Leapfrogging Problems

Patented, stay-in-place technology allows the Rapid RH™ Smart Sensor to equilibrate faster than any other test method.


2009 Copyrighted material by Wagner Meters All rights reserved. www.rapidrh.com

Recalibration Issues With Reusable Probes

ASTM F2170-09 requires reusable probes to go through a tedious process of checking calibration on a regular basis. Kanare will demonstrate the necessity and process of checking calibration as well as what to do when recalibration is needed, something totally unnecessary for stay-in-place probes.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Rapid RH Solves the Problem of Recalibration

The Rapid RH™ Smart Sensors come from the factory calibrated and do not need to be recalibrated like reusable probes.


2009 Copyrighted material by Wagner Meters All rights reserved. www.rapidrh.com

Best Locations to place Relative Humidity Tests

Kanare discusses strategic points to place relative humidity probes not only to meet ASTM F2170-09 standard, but to help monitor problem areas.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Why You Can Trust Relative Humidity Probes

A floor covering system sees relative humidity, not vapor emission at the interface with the concrete slab. For this reason, testing a slab’s internal relative humidity is the most useful method for determining a slab’s moisture condition as it relates to floor coverings/coatings.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Adhesives Moisture Tolerances Vary

Kanare discusses the effect of RH on adhesives and how that can help you determine the best product to put on your slab.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

In-Situ RH Stability

As opposed to calcium chloride testing’s extreme sensitivity to changes in ambient (room) conditions, at-depth RH testing is minimally affected by changes in ambient conditions.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Kanare's Summary

In situ relative humidity testing is clearly the most useful and scientifically valid tool for determining the moisture condition in a concrete slab that will receive a moisture-sensitive floor covering. With over $500 million spent on mitigating flooring failures each year, understanding moisture in concrete and being acquainted with the best tools in the industry is what may stand between you and the next flooring failure.

2009 Copyrighted material by CTLGroup. All rights reserved.
Used with permission by Wagner Meters

Real-world Issues in the Field


Preparing you for questions when on the job site.


2009 Copyrighted material by Wagner Meters All rights reserved. www.rapidrh.com

Resources


To learn more about relative humidity testing, please see the following information.


2009 Copyrighted material by Wagner Meters All rights reserved. www.rapidrh.com