Hardwood Floors June/July 2026

By Damian Bush

THICK VERSUS THIN COATS

heavy film thickness. Applying products too thick or too thin can lead to improper curing, adhesion problems, or inconsistent results. For this reason, it is critical to review product labels and understand technical data sheets (TDS) for each coating system being used. Understanding why these specifications exist requires a look at how finishes are developed and tested by the manufacturer, which leads to the next part of the discussion. When chemists develop water-based finishes, they test the limits of their formulations under a wide range of conditions. The coverage rate listed on the product TDS represents a target application range where the finish is expected to level properly, dry consistently, and develop the intended film properties. This recommended range reflects what the manufacturer has determined to be the optimal balance between user friendliness, appearance, and long-term performance. Deviation from these recommendations can lead to performance-related problems including poor leveling, drying issues, reduced chemical resistance, diminished wear-resistance, and an overall undesirable appearance to name a few. Most finish manufacturers will suggest staying toward the lower end of the recommended coverage range for optimum results. Staying within the recommended coverage rates you will find that open working time is maximized, flow and leveling is better (even overcoming some application errors), slower penetration of harmful fluid spills, extended service life, and an overall film thickness that ensures coating performance as intended.

Any discussion about coating thickness should begin with the understanding that not all finishes are designed to have the same film build. While many water-based finishes specify a familiar 350 to 500 square feet per gallon coverage rate, not all fall into this category. For example, roller applied hardwax oils have a coverage range of 800 to 1,230 square feet per gallon depending on brand and system. Likewise, certain color-treating sealers, reactive products, and liquid moisture or vapor barrier systems are not intended to be applied at

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