Correctly Conducting Cross-Hatch/Cross-Cut Tests

Photos courtesy of Steve Marley | Johnson Premium Hardwood

For the past 16 years, I’ve held the position of technical director and claims manager for a nationally known wood flooring manufacturer in Southern California. One of my responsibilities is to review newly submitted claims and, if necessary, arrange to have the floor inspected by an NWFA Certified Wood Flooring Inspector. Once I receive the inspector’s report, I am responsible for writing the claim response letter. It goes without saying that I stay pretty busy.

As the person who is directly responsible for overseeing our claims department, it is my responsibility to address the customer’s concern(s) and to determine (beyond a question of a doubt) causation of the stated condition(s), regardless of whether the claim turns out to be manufacturing related, installation related, site-related, or a combination thereof.

I think we can all agree that as technical directors, claims managers, sales personnel, inspectors, lab technicians, etc., it is our responsibility to do our due diligence when it comes to all aspects of the claims process, as we owe this to our customers.

Now, let’s get to the meat and potatoes as to why I’m writing this article. In the last 16 years, I have not seen a cross-hatch and/or X-cut test that meets the criteria set forth by ISO 2409 Paints and Varnishes – Cross cut test. I most often see ASTM D3359 Standard Test Methods for Rating Adhesion by Tape Test, as the test used in the testing process. The concern comes when an inspector and/or laboratory technician uses their test results (be it conducted in the field or performed in the lab) to determine if the finish passes or fails an adhesion test (even though ISO 2409 Paints and Varnishes test was not developed to determine finish adhesion to its substrate).

Here are some examples of what I regularly see that invalidates the results of either the cross-hatch test/cross-cut test or the X-cut test:

  • Wrong Test Standard used in the testing process (i.e., ASTM D3359 Standard Test Methods for Rating Adhesion by Tape Test. This testing standard was developed for assessing the adhesion of relatively ductile coatings to metal substrates, not wood. When wood is the substrate, ISO 2409 should be the testing method that is utilized as it was developed for soft materials such as wood and plaster).
  • Not providing the most current revision date on test report.
  • Using the incorrect cutting tool (e.g., 11-tooth cutter vs. 6-tooth cutter for cross-hatch cutting vs. a single blade cutter for producing an X-cut, and/or 1mm tooth spacing vs. 2mm tooth spacing vs. 3mm tooth spacing) on the sample(s) being tested. Each of these tools has a specific function based on ISO 2409. Using the wrong tool for the overall thickness of the coating will produce invalid test results.
  • Failure to ensure the cutters are sharp and not dull. Dull cutters are more likely to cause chipping within the cross-hatch (lattice) and/or X-cut, which is due to the excessive downward force being exerted on the tools cutting teeth and/or blade. If/when this was to occur, the test results would be invalid.
  • Failure to determine the overall thickness of the coating so that the right cutting tool can be utilized. You simply cannot know which tool to use if you don’t know the thickness of the coating being tested.
  • Failure to contact the wood flooring manufacturer to obtain crucial information about the material being tested.
  • Performing cross-hatch and/or X-cut tests on non-flat/uneven surfaces such as hand scraped, wire brushed textured flooring and/or over open grain. Tests performed on non-flat/uneven surfaces and/or open grain will result in invalid test results.
  • Not properly identifying the test samples as per ISO Testing Standard 2409. The testing facility and/or the person conducting the field test must document each phase of the testing from beginning to end per ISO 2409, or the test will be considered invalid. In addition, the person performing this type of test must be adequately trained and certified, or the test results/report will be considered invalid.
  • Perpendicular crosscuts using a single-blade cutter and a straight edge rather than a cutting template, can/will produce inconsistent spacing between cuts and/or offset cutting lines, which will make the test invalid.
  • Cutting too deep into the substrate can/will invalidate the test results.
  • Incorrect preparation, application, and removal of the tape.
  • Lab technicians and/or inspectors who conclude that the finish failed the adhesion test based on ISO 2409 Testing Standards. Note: ISO 2409 is not a test standard for measuring adhesion. Where a measurement of adhesion is required, refer to ISO 4624 Pull-Off Test for Adhesion.

A laboratory technician who conducts the below-referenced tests in a laboratory setting or an individual who conducts a cross-hatch test or an X-cut test in the field, can’t say if a test passes or fails, as there is no pass/fail industry standard. These subjective tests produce “visual” qualitative results, not quantitative results. The wood flooring manufacturer is the only one who can set parameters for pass or fail criteria for their products. This is what labs and inspectors need to reference their test results against.

This article is meant to bring attention to a misunderstood matter. It is the responsibility of the lab technician and/or inspector conducting the test to follow the appropriate testing standards for the material being tested.

Steve Marley is the technical director for Johnson Premium Hardwood. He can be reached at

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One thought

  1. As one can see, the number of hoops one has to to jump through to have a valid and certifiable test makes each and every test result arguable. What is the thickness of the finish and how do you know? Where were you certified? I was certified in the factory by the factory. is that valid? Was the individual who certified me also certified and if so , where. What is the test for blade sharpness? This test, in my opinion, is far too subjective as there is simply no way to assure the pressure applied to the cutting edge is always the same. It is a bit different when used in the factory as it is typically done by the same person, using the same tool and the same tape and doing perhaps 100’s of tests per day enabling them to get an average. As one can see, as pointed out by Steve, this IS not, in my opinion, a test one might wish to stake their reputation on.

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