Page 79 - CFJ_Apr26

SECTOR FOCUS SUBFLOORS & SCREEDS

be really risky, especially when installing But with the right tools, you can
in-floor heating systems. responsibly identify and monitor
Concrete naturally releases moisture concrete moisture so you don’t install
through the slab’s surface from the flooring too soon.
time it’s poured until it ‘dries.’ But this Tools for concrete moisture testing
process creates a moisture gradient, Using Rapid RH in-situ probes, with
where the moisture closer to the surface the help of the C555 moisture meter,
is released faster while the moisture you can collect the data you need
deeper down takes longer to move to determine when a concrete slab
upward. So the surface of a slab can has reached the desired equilibrium
seem completely dry when there is still moisture content (EMC), allowing you
excess moisture underneath. to make more confident, informed
And that excess moisture will keep decisions about installation timing.
Jason Spangler elaborates on moving up, even if a floor covering is Rapid RH in-situ probes
thorough concrete moisture testing installed over top. Then that moisture Scientific evidence points to relative
using Rapid RH and the C555 becomes trapped between the slab humidity (RH) in-situ probes as being
surface and the flooring, which can
concrete moisture meter cause issues such as: the most reliable method for concrete
moisture testing.
• adhesive failure Strategically placing RH in-situ probes
COMPLETE CONCRETE • warping in various locations and at the correct
MOISTURE TESTING • bubbles depth within a concrete slab provide
• discoloration
the most accurate concrete moisture
WITH RAPID RH • mildew or mould measurements—not just surface
On top of that, heat from an in-floor measurements.
heating system can further complicate Drilling small holes into the concrete
APID environmental fluctuations, things because it draws even more and inserting probes at 40% of the slab’s
Rpoor materials, juggling indecisive water from the concrete slab. thickness provides ambient condition
customer requests… these can be and RH readings that let you predict
frustrating scenarios for flooring how moisture in the slab will act after a
professionals. But nothing is more floorcovering has been installed.
frustrating than flooring failures due to Wagner’s Rapid RH L6 sensors follow
hidden moisture. ASTM F2170 standards, which many
That’s why comprehensive subfloor manufacturers require for floor covering
moisture testing is essential before installations. When inserted into a slab
installing floors on top of concrete or at the right depth, Rapid RH L6 sensors
screed. And using Rapid RH along with read relative humidity levels so you can
the C555 concrete moisture meter track them and determine when the
makes for a highly effective moisture subfloor is sufficiently dry.
testing combo to ensure the subfloor is And uploading test results to the
ready for a floorcovering. DataMaster L6 app makes it easy to
We’ll discuss the whys and hows by keep track of data from all installed
looking at: sensors.
• Concrete moisture and its impact C555 concrete moisture meter
• Tools for concrete moisture testing Wagner’s C555 concrete moisture meter
• Best practices for concrete moisture will evaluate moisture up to 0.5inch
testing below the concrete’s surface. This will
• Testing for in-floor heating installation provide the data you need to identify
• Using Rapid RH and C555 for complete moisture ‘hot spots’ and determine the
moisture assessment most effective areas to install Rapid RH
Let’s first review concrete moisture and in-situ probes. This makes the C555
its impact. a valuable tool for optimising sensor
Understanding concrete moisture and placement and ensuring more precise in
its impact Use the C555 handheld moisture meter to find situ RH testing results.
Not monitoring moisture in concrete can moisture hotspots in your concrete slab You can also use the C555 meter 

‘Concrete naturally releases moisture through the
slab’s surface from the time it’s poured until it ‘dries’’

www.contractflooringjournal.co.uk 79
@CFJMagazine CFJ April 2026