Hardwood Floors December 2025/January 2026

tangential DCC is the applicable value, even though that is rarely the case. In our paper, we found that a grain angle steeper than 20 degrees from true tangential was common in our boards. Because you cannot measure the grain angle in an installed floor, it makes sense to include uncertainty. We don’t use grain angle directly in our calculations, so instead we can include uncertainty in the tangential DCC value itself, though please note that the DCC itself, irrespective of board grain angle, has its own variability and uncertainty. A PRACTICAL EXAMPLE ON A WOOD FLOORING JOB To explain what we mean, let’s look at a practical example from a wood flooring jobsite. Say an installer notices a slight difference in board width between material from two bundles of nominally identical hickory flooring from the same manufacturer. The installer measures the MC and width of 20 boards from the suspect bundle. The average MC is 8.0 percent and the average board width is 2.938 inches. The manufacturer’s specification is 3 inches with a tolerance of 0.008 inch. The installer suspects the boards had a high MC at the time of manufacture.

swelling of the whole set of boards – we overcome uncertainty about any one board or measurement by averaging measurements of many boards. UNCERTAINTY We all know what this word means in a casual context, but in science, “uncertainty” is the idea that a value we measure will have some portion of the measurement that is error – some portion that could be specific to that single measurement – and thus a degree to which that particular measurement may not be reflective of the larger thing we are trying to estimate. For solid wood flooring and DCC calculations, we have several sources of uncertainty: uncertainty in board or gap measurements, uncertainty in wood MC, uncertainty in board grain angle, and uncertainty in the DCC value itself. When we do a traditional calculation using DCC, we implicitly assume that we are using the true values for each of the inputs, even though it is widely known and accepted, for example, that a moisture meter – even when properly calibrated – could easily give a MC value ±1 percent. By mathematically including uncertainty, we can calculate more scientifically defensible numbers. Okay, fine, you might say, in theory uncertainty matters, but how much of a role does it play in my calculations for a specific job? By incorporating uncertainty, we get a range of values that represent realistic variation and error (uncertainty) inherent to our measurements. For example, in an installed floor, it isn’t realistic to measure the actual grain angle of the boards. Instead, for flatsawn flooring we assume the full

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