What is Janka Hardness Rating?
The Janka hardness test measures the resistance of a type of wood to withstand denting and wear. It measures the force required to embed an 11.28 mm (0.444 in) steel ball into wood to half the ball’s diameter. This method leaves an indentation. A common use of Janka hardness ratings is to determine whether a species is suitable for use as flooring.
It should be noted that the test is meant to be used only for “unfinished, open grain flooring” manufactured before the 1990s. With the advent of pre-finished flooring in which hardwood floors are treated with aluminum-oxide based sealers that often double or triple the dent and scratch resistance of the flooring, the Janka Hardness test has been essentially rendered useless in modern-day hardwood flooring, unless the end user is purchasing unfinished flooring or oil coated flooring.