The Janka Hardness Scale was developed in the early 1900s as a way to test the density of a wood species, or specifically the resistance to denting of that wood species. To determine the Janka rating, a 0.444” steel ball is pressed into the surface of a 2” x 6” piece of wood with a moisture content of about 12%. The LBF (Pounds-Force) required to embed half the sphere’s body into the piece of wood is the “Janka Rating.” For example, it would take 950 LBF to embed half of the steel ball into a piece of American Cherry.
This rating is highly used in the construction industry and is most used when referring to hardwood flooring or similar applications. It is a great indicator of how resistance to denting a wood species is when considering repetitive foot traffic and the potential impact from dropped objects. Which is why it is very important to choose a wood species with a high Janka rating for your stair treads. Typically, a rating of 900 or above is acceptable for treads and hardwood flooring.
When considering our DriveTite or RodTite product, it is recommended that you use a wood species with a Janka Rating of 690 or above.