Castor Chair Resistance Explained Glue-Down LVT · EN 425 · Rolling Load · Adhesive Shear
Castor chair resistance describes how well glue-down LVT handles repeated rolling chair movement — evaluated by the EN 425 or ISO 4918 test method. For glue-down systems, rolling loads affect not only the surface wear layer but also the adhesive bond at plank edges: concentrated caster loads can create adhesive shear that lifts plank edges if the adhesive is under-cured or the bond area is insufficient. Reference-only: no product recommendations.
EN 425 tests rolling chair resistance with a defined caster type (hard or soft), load, and cycle count — a pass indicates adequate performance under those specific conditions. For glue-down LVT, the adhesive must be fully cured before rolling loads are introduced. Some products specify chair mats or limit caster hardness in the installation guide.
EN 425 / ISO 4918 Test Method
What the test evaluates
The EN 425 (equivalent to ISO 4918) castor chair test cycles a wheeled office chair apparatus across a flooring sample a specified number of times under a defined load. After testing, the surface is evaluated for changes in appearance, wear, or surface defects. The test is pass/fail based on visual assessment criteria. EN 425 specifies hard casters (Type W, polyamide) and soft casters (Type R, polyurethane rubber) — the hard caster test is significantly more demanding because hard materials concentrate contact stress at the caster edge rather than distributing it across a larger contact area.
Reporting the result
Manufacturers report EN 425 results as a pass or fail for the caster type and load specified. Some report passing both the hard and soft caster tests; others only report the soft caster result. When reviewing spec sheets for commercial environments with hard nylon office chairs, confirming which caster type was tested is important — passing the soft caster test does not guarantee adequate performance under hard casters. Some products also specify a chair mat requirement as a condition of the warranty, even if the product passes EN 425.
Castor Resistance in Glue-Down Installations
For glue-down LVT, castor resistance involves both the wear layer surface and the adhesive system. Rolling loads concentrate at the plank edges where casters change direction, creating a peeling stress on the adhesive bond at the seam. If the adhesive has not fully cured, or if the bond area is reduced (hollow spots from under-coverage or poor rolling), this peeling stress can lift plank edges. Adhesive cure time should be observed before rolling chair traffic is introduced. The adhesive selection — particularly shear strength and peel resistance — contributes to castor performance in ways that the surface wear test alone does not capture.
Spec Sheet Checklist
- Confirm the test standard (EN 425 or ISO 4918) and which caster type was tested (hard polyamide or soft polyurethane).
- Check if the rating applies to the full system (floor + adhesive) or to the flooring sample only.
- Review the installation guide for any chair mat requirement or caster hardness limitation in the warranty.
- Confirm the adhesive cure time before rolling loads are introduced — typically 24–72 hours minimum.
- Pair with indentation resistance data for a complete picture of static and dynamic load performance.
FAQ
Does castor chair resistance guarantee no damage? ⌄
No. The EN 425 or ISO 4918 test evaluates performance under a controlled protocol with a specified caster type, load, and cycle count. Real-world casters vary in hardness, diameter, and edge profile, and actual loads may differ from the test conditions. A floor that passes the standard test will perform adequately under the tested conditions, but may show wear or adhesive shear if subjected to harder casters, heavier loads, or significantly more cycles than the test represents.
Is castor chair resistance more relevant for glue-down than rigid core? ⌄
Castor chair resistance is relevant for both installation types, but the failure mode differs. For glue-down LVT, rolling loads can cause adhesive shear at the plank edges if the adhesive has not fully cured or if the bond is weakened by moisture. For rigid core floating LVT, rolling loads can cause surface wear and also stress the locking joints. Castor chair resistance is most commonly specified for commercial glue-down LVT in office and healthcare environments where rolling chair traffic is continuous.
What caster type is used in the EN 425 test? ⌄
EN 425 specifies a hard polyamide (Type W, hard) or soft polyurethane (Type R, soft) caster of defined diameter and load, cycled across the flooring surface a defined number of times. The hard caster test is more demanding — hard nylon or polyamide casters concentrate more stress per unit area than soft PU casters. Some manufacturers report passing only the soft caster test, while others pass both. The caster type used in testing should be noted when comparing products for environments with hard caster office chairs.
How long after installation should rolling loads be avoided? ⌄
Most adhesive manufacturers specify avoiding rolling loads (including castor chair traffic) for 24–72 hours after installation, until the adhesive has reached sufficient bond strength. Some polyurethane adhesives require longer cure times before full rolling load capacity is achieved. The flooring warranty often requires that rolling load restrictions be observed during the cure period — premature rolling traffic that causes plank lifting or adhesive shear during the cure window is typically excluded from coverage.
Related specs to compare
Reference-Only Information
This page provides general informational reference about castor chair resistance for glue-down LVT. It does not provide installation guidance, professional advice, or product recommendations.