Preventing Flooring Failure due to Excessive Moisture

10 June 2024

High moisture content in substrate is the second biggest problem in conventional solvent free epoxy flooring application. Unexperienced applicator or coating manufacturer tends to take the project without checking how severe is the moisture condition in substrate. On certain worst case, it can lead to a problematic repair and claim, which at the end consume all the project margin.

causes of coating failure in construction Figure 1. Causes of coating failure in construction

If only the applicator or manufacturer prior application already know the moisture content in substrate in this particular concrete, then the correct system can be applied. It can also lead to a purchase of another high performance suitable flooring system or complimentary moisture barrier membrane, instead of conventional epoxy flooring which increase the flooring lifetime.

Unwanted Impact of Moisture in Substrate

1. Bubbling

Moisture can cause bubbles to form in epoxy before it has cured. This happens when moisture rising to the surface meets the liquid epoxy. It cannot fully escape and creates bubbles at the surface as it rises. The phenomenon is different from osmotic blistering.

bubbling in epoxy

Figure 2. Bubbling on epoxy
(source: Advanced Floor Coatings) 

2. Peeling or Flaking Epoxy

When moisture is present underneath cured epoxy, it can interfere with the bond between the epoxy and the concrete. When the moisture rises it cannot pass through the surface of the epoxy. When trapped, it puts pressure on the epoxy and causes it to lift or peel from the concrete floor.

Figure 3. Peeling on epoxy
(Source: Advanced Floor Coatings)

Preventive Action: Moisture Measurement

To prevent failure due to excessive moisture, a moisture measurement method is necessary. In situ and Hood Relative Humidity tests as per BS 8201, 8203, 5325 and ASTM F2170, is the most common test conducted to test moisture. ASTM F2420 is used to be conducted to test moisture however ASTM board withdrawn the standard with no replacement due to precision and biased result.

The latest and the most convenience to test moisture is ASTM F2659-10.

  • BS 8201:2011 Code of practice for installation of flooring of wood and wood-based panels.
  • BS 8203:2001 Code of practice for installation of resilient floor coverings (+A1:2009).
  • BS 5325:2001 Code of practice for installation of textile floor coverings.
  • ASTM F2170-02 Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes.
  • ASTM F2420-05 (2011) Standard Test Method for Determining Relative Humidity on the Surface of Concrete Floor Slabs Using Relative Humidity Probe Measurement and Insulated Hood (Withdrawn 2014)
  • ASTM F2659-10 (2015) Standard Guide for Preliminary Evaluation of Comparative Moisture Condition of Concrete, Gypsum Cement and Other Floor Slabs and Screeds Using a Non-Destructive Electronic Moisture Meter.

Tramex Moisture Meter

tramex moisture meter

Tramex has been manufacturing Moisture Meters for the Industrial Flooring industry for more than 30 years. They supply individual moisture meters, both non-destructive and with probe attachments, as well as complete kits. These instruments and kits are an essential part of an Industrial Flooring Contractor’s toolbox. In fact the in situ and Hood Relative Humidity tests as per BS 8201, 8203, 5325 and ASTM F2170, F2420 can be conducted with the Tramex CMEX II and reusable Hygro-i ® probe.

One of the most favorite choice is Tramex CME 4 to test moisture. Instant and non-destructive tests per international standard ASTM F2659 with the Tramex CME4, a handheld electronic instrument used for testing moisture content in concrete slabs and other floor screeds, featuring Carbide Method equivalent scales for concrete and anhydrite screeds. Precise and easy to use, the CME4 allows the user to make multiple tests over a large area in the shortest possible time.

Tramex Moisture Meter Features

  • Clear easy-to-read analogue dial.
  • CM Carbide Method moisture content equivalent readings.
  • No need to probe, drill or mechanically damage the surface.
    Instant and precise readings deep into the surface.
  • Non-destructive in operation.
  • Hold function “freezes” meter reading when inspecting areas where the meter face is not visible and for easy recording of readings.
  • Reproducible results.
  • Spring-loaded contact pins compensate for uneven concrete and boost signal penetration.

Working Mechanism

The instrument operates on the principle that the electrical impedance of a material varies in proportion to its moisture content. The electrical impedance is measured by creating a low frequency alternating electric field between the electrodes as illustrated in the diagram below.

Figure 4. How Tramex CME 4 Works

How to Use Tramex Moisture Meter

tramex moisture meter tutorial

  1. Remove any dust or foreign matter from the Concrete Encounter CME 4 electrodes before commencing tests. Make sure that the floor slab being tested is clean and bare and free from dust, dirt or standing water.
  2. Push the ON/OFF button and press the instrument directly onto the surface of the material being tested ensuring that all of the electrode spring loaded pins are fully compressed. Read the moisture measurement from the appropriate scale of the moving coil meter dial
  3. On a rough surface, take a number of readings in close proximity to one another. If the readings vary, always use the one with the highest value
  4. On a normal smooth surface it is also recommended that a number of tests in close proximity to each other be carried out, as the distribution of moisture tends to become erratic as concrete dries out. Use only the highest reading.
  5. Always refer to the adhesive and/or floor covering manufacturer’s recommendations for the acceptable moisture content levels of concrete or floor screeds.

Tramex Moisture Meter Warranty

Tramex warrants that this instrument will be free from defects and faulty workmanship for a period of one year from date of first purchase. If a fault develops during the warranty period, Tramex, at its option, will, at its absolute discretion, either repair the defective product without charge for the parts and labour, or will provide a replacement in exchange for the defective product returned to Tramex Ltd. This warranty shall not apply to any defect, failure or damage causedby improper use or improper or inadequate maintenance and care. In no event shall Tramex, its agents or distributors be liable to the customer or any other person, company or organisation for any special, indirect, or consequential loss or damage of any type whatsoever (including, without limitation, loss of business, revenue, profits, data, savings or good will), whether occasioned by the act, breach, omission, default, or negligence of Tramex Ltd., whether or not foreseeable, arising howsoever out of or in connection with the sale of this product including arising out of breach of contract, tort, misrepresentation or arising from statute or indemnity. Without prejudice to the above, all other warranties, representations and conditions whether made orally or implied by circumstances, custom, contract, equity, statute or common law are hereby excluded, including all terms implied by Section 13, 14 and 15 of the Sale of Goods Act 1893.

Warranty Claims: A defective product should be returned shipping pre paid, with full description of defect to your supplier or Tramex at address shown on back page of this booklet.

Equipment Calibration

For regular on-site assessment of your Concrete Encounter CME 4, a calibration check-plate is available from Tramex. Should it be found that readings are outside the set tolerances, it is recommended that the Concrete Encounter CME 4 be returned for re-calibration. Calibration adjustments should not be carried out by anyone other than Tramex or their authorised service provider who will issue a calibration certificate on completion.

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