Solid timber is very hard, so timber floors will last for decades. They may be re-sanded from time to time.
The hardness of various types of timber will vary according to the species of wood. The harness is measured by the Janka test and indicated by the Janka number.
The Janka test will press a solid 0.444 inch (11.28mm) ball into the timber’s surface. The force in Newtons required to press the ball to half of its diameter is the Janka Number. This number is usually given in kilo Newtons (kN).
Timber used for flooring is usually between 6kN and 12kN, though some less common wood can have a Janka rating as high as 16kN.
The Janka rating is a good indication of how well a wood floor will withstand wear and tear. But hardness is not the same as strength. Not does it indicate how a floor will feel underfoot.
The Janka test was originally designed and used for wood. It can be applied to bamboo, but the results are misleading. Good bamboo can have a high Janka number, and will be extremely long lasting. But some bamboo is still prone to surface scratching. A high Janka number is good, but there are other factors when considering a floor’s durability.
Some foreign markets measure Janka in pounds force rather than Newtons. The units of measurement must be checked before comparisons are made.