The Janka Hardness scale is used to determine the hardness of wood. It is a measure of the force required to insert a steel ball of 11.28 mm into wood to a depth of half the ball’s diameter. At that depth it makes an impression of exactly 100 square millimeters. The higher the Janka rating, the harder the wood. The Janka hardness chart is a relative table comparing the hardness of various woods. As an example, eastern white pine at 380 is a soft wood whereas Brazilian walnut (Ipe) at 3680 is a hard wood. Most woods are usually compared against red oak as a base point. Red oak has a 1260 Janka rating.

Generally a hard wood is more durable than soft wood, which is why it is preferred for flooring. The Janka hardness scale is a good reference. There are however, other desirable characteristics in wood flooring and these too must be carefully considered. Certain woods with a high Janka ranking tend to become brittle and develop cracks while others might warp after some time. Some woods, because of inherent chemicals in the sap, have a natural resistance to pests and termites. For this reason the relative characteristics of different woods should be carefully evaluated before making a decision. A number of problems are eliminated if the wood is properly cured after harvesting and if it is acclimated before installation. When purchasing wood flooring, look to the manufacturer and the warranty offered.

When selecting a wood, the location also determines selection. High traffic areas or areas susceptible to abuse naturally demand a harder and more durable wood. Such locations are staircases and passages which are not just subject to hard use but often have to contend with children and dogs and consequent likelihood of scratches and scuffs. Again places liable to become scratched because of furniture movement demand harder, more durable flooring. The Janka Hardness Scale is a good guideline in selection.