Indentation Resistance Explained Glue-Down LVT · Static Load · ISO 24343 · Furniture Protection
Indentation resistance measures how much permanent denting glue-down LVT sustains under a concentrated static load — simulating heavy furniture, equipment feet, or high-heel concentrated loads. It is tested by applying a specified force through a small indenter for a set time, removing the load, allowing recovery, and measuring the residual indent depth. Lower residual indentation is better performance. Reference-only: no product recommendations.
Indentation resistance is determined primarily by core density and backing hardness — not wear layer thickness. The standard test is EN ISO 24343-1, which measures residual indent depth after load and recovery. For heavy commercial use (Class 33), the typical maximum residual indentation is 0.15 mm. Protective pads under furniture are recommended regardless of test results.
Indentation Test Method
EN ISO 24343-1 (residual indentation)
EN ISO 24343-1 applies a specified force (commonly 392 N — approximately 88 lbs) through a flat-ended cylindrical indenter of defined area to a flooring sample for a set time (typically 24 hours). After the load is removed, the sample is allowed to recover for the same period. The difference between the original thickness and the final thickness at the indentation point is the residual indentation, reported in millimeters. A result of ≤0.15 mm residual indentation is required for Class 33 (heavy commercial) products. Results above 0.25 mm indicate a product more suitable for lighter use applications.
ASTM F1914 (short-term indentation)
ASTM F1914 measures both immediate indentation (under load) and residual indentation (after load removal and recovery) for resilient flooring. It is commonly used in North American specifications. The test applies a 150-lb load through a 0.1 sq in indenter for a specified period. Results are compared against pass/fail criteria in the applicable product standard. ASTM F1914 results cannot be directly compared to EN ISO 24343-1 results due to differences in load, indenter geometry, and test duration.
What Determines Indentation Resistance
Indentation resistance in glue-down LVT is primarily determined by the density and compressibility of the core and backing layers. Denser core materials — such as limestone-filled PVC composites or high-density virgin PVC — provide more resistance to permanent deformation under point loads. In glue-down applications, the adhesive bond to the subfloor creates a rigid support platform under the plank, which significantly improves indentation resistance compared to the same product installed as a floating floor over a compressible underlayment. A soft or compressible underlayment under a floating floor can increase residual indentation substantially, which is one reason glue-down LVT often outperforms floating LVT in indentation tests at the system level.
Spec Sheet Checklist
- Find the test standard (EN ISO 24343-1 or ASTM F1914) and the reported residual indentation value in millimeters.
- Confirm whether the result is for the product alone or for the full system (including subfloor support conditions).
- Match the residual indentation value against the use class requirement — ≤0.15 mm for Class 33 (heavy commercial).
- Note whether temperature conditions are specified — results may differ at elevated temperatures.
- Review the installation guide for furniture protection pad recommendations, which apply regardless of the test result.
FAQ
Does a thicker wear layer improve indentation resistance? ⌄
Not directly. Indentation resistance is primarily determined by the density and compressibility of the core and backing layers — not the wear layer. The wear layer is thin (6–28 mil / 0.15–0.7 mm) and does not contribute meaningfully to resisting downward load from furniture or equipment. A denser core material resists indentation better than a softer or foam-containing core. The adhesive-to-subfloor bond in glue-down LVT provides a rigid support platform that also contributes to indentation resistance by eliminating springiness under point loads.
Is indentation resistance required for commercial spaces? ⌄
Many commercial specifications and flooring classification systems reference maximum allowable residual indentation values. EN ISO 24343-1 sets limits for resilient flooring indentation — the maximum residual indentation for Class 33 (heavy commercial) is typically 0.15 mm or less under the standard test load. Project specifications for healthcare, education, or retail environments often specify minimum indentation resistance thresholds that must be verified against the product's reported test result.
What is the difference between static and dynamic indentation? ⌄
Static indentation measures the permanent dent remaining after a concentrated load is applied for a defined time (typically 24 hours) and then removed and allowed to recover — relevant for furniture and equipment that remains in place. Dynamic indentation measures temporary deformation under a moving load — relevant for rolling equipment and foot traffic. The EN ISO 24343-1 residual indentation test is a static test. Dynamic performance is partially captured by the castor chair test (EN 425) for rolling loads.
Does temperature affect indentation resistance in glue-down LVT? ⌄
Yes. LVT is thermoplastic — its core and backing materials soften as temperature increases, reducing resistance to deformation under load. A floor that performs well at standard room temperature may show greater indentation under the same load at 90°F, particularly in sunlit areas or near heating equipment. Most indentation tests are conducted at standardized temperatures, so test results represent performance under those specific conditions. In warm climates or spaces with significant heat gain, indentation resistance under elevated temperature conditions may be a practical consideration.
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Reference-Only Information
This page provides general informational reference about indentation resistance for glue-down LVT. It does not provide installation guidance, professional advice, or product recommendations.