How Hardness and Density Are Measured

• The density of most objects, including wood, is calculated by a simple formula: grams per cubic centimeter. A simple way to picture this is to imagine cutting out a cube of wood measuring precisely one centimeter in every direction and weighing it on a gram scale. The higher the gram weight, the denser the wood. Calculating the hardness of wood takes a little more effort. The Janka Hardness Test is the standard measurement. This test measures the force necessary to halfway embed a .444-inch steel ball into a piece of wood. The more force it takes, the harder the wood.
  
  

Common Hardwood Flooring Species

• Wood densities are classified as soft, heavy, medium heavy, very heavy and ironwoods, from lightest to heaviest. The most common species used to make hardwood include oak, maple, cherry, pecan and hickory. Oaks have different densities, depending on the species, but are usually classified as heavy or very heavy woods of medium hardness. Maples are heavy or medium heavy of medium hardness; cherry woods range from very heavy to medium heavy and are relatively soft; pecan is heavy and of medium-high hardness; and hickory is heavy with medium-hard wood.
  
  

Uncommon Hardwood Flooring Species

• Wood from mesquite, black walnut, yellow birch, teak, pine and fir are less common for making hardwood floors. This is due to popularity, quality, availability or high cost. Mesquite is the hardest wood used by many flooring manufacturers and is classified as a very heavy, dense wood. Black walnut and yellow birch are heavy woods and relatively soft, although yellow birch is slightly harder. Teak is a heavy wood but softer than either black walnut or yellow birch. Pine and fir are light weight, softwoods, but are also used for flooring commonly referred to as "hardwood."
  
  

What Density and Hardness Mean For Flooring

• The density and hardness of a wood translate to durability in flooring. Dense, hardwood is less likely to be damaged and more likely to withstand the everyday occurrences in any living or working space, such as heavy traffic, children's play, spills and the impact of falling objects. However, a quality manufacturing and installation job, as well as the choice of finish, play important roles in a floor's durability. For instance, acrylic-impregnated finishes inject high-strength acrylic components directly into a wood's grain, making it more durable than it would naturally be to indentations and other damage.