The Janka Hardness Scale - Not just a number

When you think of the hardest wood you know, does the ‘mighty’ oak come to mind? While very hard and durable, in reality, oak ranks as the fourth hardest of the North American hardwoods. Hickory, with a Janka Hardness rating of 1820, leads the pack, followed by maple and then ash. So just what is Janka Hardness? The Janka Wood Hardness scale is a way to measure a wood’s resistance to dents, scratches and wear. The higher the Janka rating, the more resistant that particular wood is. The Janka Hardness scale is commonly used in the flooring industry as a way to compare types of hardwood flooring for both practical durability and for the wood’s ability to be nailed, sawn, planed, routed or sanded. At Gaylord Hardwood Flooring you’ll find that all the woods we sell include the Janka Hardness rating in the description.

Janka Hardness Scale for Wood

How is Janka Hardness Measured?

Invented in 1906 by Austrian wood researcher Gabriel Janka, the Janka Hardness Test is an adaption of the Brinell Hardness Test for metals. The Janka Hardness test measures the pounds of force (lbf) it takes a to drive an 11.28mm (.44”) diameter steel ball halfway into the board that’s being tested. This method was chosen so that the result would leave an indention 100 square millimeters in size. Testing done on the surface of the board, perpendicular to the grain, is called a test of ‘side hardness’ while testing the cut surface of a stump is called a test of ‘end hardness.’ So will every board from a certain type of wood result in the exact same pounds of force when being tested? That’s not possible since the hardness of wood usually varies with the direction of the wood grain and will deviate from one piece of lumber to another. However, most pieces of wood in the same species will be plus or minus 10% of the species rating on the Janka Hardness Scale.

Why is the Janka Hardness rating important?

Hardwood flooring is a big investment and you want to be sure you have the right choice for your situation. For example, if you have kids or dogs you already know how hard they can be on flooring. In that case you’ll want to choose a wood flooring with a high Janka rating such as Hickory with its 1820 rating. Or depending on the type of grain that appeals to you, you may opt for Maple with a rating of 1450 or Ash with a rating of 1320. So when you visit our Tweed Showroom to pick out your hardwood flooring, be sure to let our sales people know just where the flooring will be installed and what kind of wear and tear it will be subjected to. They’ll be happy to explain what the Janka Rating numbers mean and which hardwood flooring will best suit your situation.