Hardwood Flooring Mechanical Properties - What Do They Mean?

There are a number of mechanical properties industry insiders use to describe and qualify different species of hardwood flooring. This vocabulary is used to talk about a wood's strength, density, its tendency to shrink or swell, and other hardwood features. But if you are just starting your search for new hardwood floors you probably aren't familiar with these terms, and you probably don't know why they're so important. The following are the six most commonly used hardwood flooring properties, what they refer to, and why knowing what they mean can help you pick the perfect flooring material for your home or office.

Hardness
Officially called Janka hardness, this property measures how resistant a specific species is to indentation. It is determined by measuring the pounds of force required to embed a small ball (about .444" in diameter) into the wood a distance of half its diameter (.222"). The larger the number, the harder the wood. Most exotic hardwoods have higher Janka hardness ratings and are very great for high-traffic areas or in rooms that hold heavy furnishings, such as pianos and entertainment centers.

Modulus of Rupture (MOR)
Also called strength, a wood's MOR refers to the wood's load-bearing capacity - or, the amount of force that is required to break the wood. It is measured in pounds-per-square-inch (psi), and, like Janka hardness, the higher the number the stronger the wood. It is another property that is important to know if you plan on using the flooring in a high-traffic area or a room with heavy furnishings.

Modulus of Expansion (MOE)
MOE is also called stiffness and is a measurement of the wood's resistance to bending. It is measured in pounds-per-square-inch and is expressed in exponential terms - for instance, the MOE of Douglas Fir is 1,950,000 psi, or, 1,950 1000 psi. This property is a good indicator of how likely your floors will be to buckle. The higher the MOE, the less likely they'll warp or buckle.

Density
Density is measured in KG per cubic meter (KG/m3) and essentially is the measurement of you much wood is actually packed into a cubic meter. Hardwood species with higher densities are heavier and harder, which can be great for high traffic areas or exterior projects. Hardwood flooring with high density is also more resistant to water and boring insects, making it a great choice for kitchens, bathrooms, and other high moisture rooms of the house.

Tangential Shrinkage
This mechanical property measures how likely the species will be to shrink during the drying process. It applies to the width of the board and is expressed as a percentage. The lower the percentage, the less likely the wood will shrink, reducing the amount of warping and buckling you'll experience.

Radial Shrinkage
Like tangential shrinkage, radial shrinkage measures how likely the wood will shrink though the thickness of the board. It is also expressed as a percentage and, when considered with the wood's tangential shrinkage, tells you how dimensionally stable a floor will be. If the two numbers are close together, the wood is more stable and is less likely to warp or buckle.

The hardwood flooring professionals at Wood Monsters are experts in hardwood flooring mechanical properties. Contact us today to learn more.

The mechanical properties of hardwood flooring are important to know before buying.