The hardness of wood is measured by a scale known as the Janka hardness test. Technically, the test measures the force needed to embed a 0.444-inch steel ball to half its diameter in a piece of wood. But all you really need to know is the higher the rating, the more difficult it is to dent the wood.
The Janka scale measures all sorts of domestic and exotic hardwoods, with ratings ranging from just over 300 (very soft) to well over 3000 (very hard). Any wood with a rating above 1800 is considered extremely durable, while woods that rate between 1200 and 1800 are mid-range and well-suited for residential use. Anything with a rating below 1200 should only be used in low-traffic areas.
Here are the Janka ratings for some of the most popular hardwood varieties:
- Brazilian cherry: 2350
- Hickory: 1820
- Maple: 1450 (hard variety) and 950 (soft variety)
- White oak: 1360
- Northern red oak: 1290
- American walnut: 1010
- American cherry: 950
- Southern yellow pine: 870 or 690, depending on variety
Keep in mind that factors other than the Janka rating affect a floor’s durability. For engineered wood floors, the quality of the core materials makes a big difference. The thickness of the grain plays a role, as does the quality of the top coating. Even within a certain species, there are slight variations in hardness. Also, keep in mind that harder woods can be more difficult to install, which can lead to other complications.
The Janka scale is one of many considerations when shopping for hardwood flooring, but it shouldn’t be your only consideration.