What is a Janka rating and how important is it?

The Janka* hardness test is designed to measure the resistance of a sample of wood to denting and wear.   The test is one of the “Standard Test Methods for Evaluating Properties of Wood-Base Fiber and Particle Panel Materials”.  Sound fascinating, huh?  Well, fortunately, it’s not a test you have to perform yourself.  As you have probably discovered, the results of the test on a huge variety of woods can be found all over the Internet, and, in fact, the ratings of most of the woods sold here at Prestige Flooring and Interiors can be found on the chart below.

For flooring, one of the most important criteria in choosing the right wood is its resistance to denting as a result of pressure from, say, a stiletto heel, the tip of a small chair leg, a pet’s toenail, etc.  The test, to some degree, replicates such impacts by embedding a .444-inch metal ball to one half the ball’s diameter into the surface of a clear (knot-free) wood specimen.  Two areas on the face of each specimen are tested, and the information is recorded and averaged.  A species’ Janka rating is a measurement of the amount of force (usually in pounds of force, or LbF) required to do this, and there is a standard deviation associated with each species.

What is important to understand is that there are many factors that will affect a floor’s durability beyond the Janka rating of its species.  Remember that Janka testing is done on solid, unfinished wood with a moisture content of around 12%.  Wood flooring, however, has been milled at about 6-9% moisture content and, by the time you walk on it, has been treated with several layers of protective finish.  With engineered wood flooring, you also have different materials underneath the hardwood layer, which will significantly affect the floor’s overall “hardness”.   Add to that variances in the quality of manufacturing and finish, and even grain direction, and you can see that a high Janka rating is by no means an assurance that your floors will stay clean and beautiful for all time.

In reality, all flooring is subject to damage and wear.  In the end, the primary factor in how well your wood floors hold up over the years is how you treat and care for them.  While it is advisable to start with a harder wood if you anticipate high traffic and rough use, keeping your floors clean, protecting them with rugs in high-traffic areas, and choosing woods and finishes more likely to mask scratches and dents can be just as, if not more important.