What are Wood Hardness Ratings?

15 Jun What are Wood Hardness Ratings?

When it comes to choosing a hardwood floor, you want something that’s durable while giving you the feeling you got your money’s worth.  For this reason, choosing a wood that can withstand wear and tear should be high on your list.  But how can you decide which type of wood will prove to be the longest lasting?  To help answer questions such as this, the lumber industry has created a measurement system known as the Janka hardness scale.  To help you make sense of this system we provide an article to answer the question of, “What are wood hardness ratings?”

The Janka Hardness Test

The Janka hardness scale is the most common measurement used to determine the durability of a certain species of wood when used as flooring.  It rates the resistance of the wood by measuring the amount of force needed to embed an 11.28mm steel ball bearing halfway into a knot-free sample of heartwood.  The resulting number, typically expressed as pounds-force in North America, denotes the hardness of the wood.  The higher the number, the harder the wood.  

Hardwoods Versus Softwoods

The terms hardwood and softwood can be confusing since there are many instances of softwoods that have a higher Janka rating than hardwoods.  For example, balsa, known as a very light and delicate wood is actually a hardwood, whereas the Yew tree, a softwood, is much harder than the well known hardwood, oak.  And while it’s true that hardwoods populate the very top ranks of the Janka hardness chart, the names hardwood and softwood are actually a biological distinction rather than a true measure of their relative hardness.  

The Hardest Woods?

North American wood species generally don’t rank at the top of the Janka hardness charts.  These top ranks are populated by what’s known as exotic species, or those from areas such as South America and Southeast Asia.  Rosewood, Ebony and Cumaru are some of the hardest wood species which all originate from Central and South America.  However, some of the hardest “woods” aren’t actual woods at all.  Both bamboo and eucalyptus, often used as flooring materials, can have Janka ratings higher than any hardwood.  But the fact is they’re actually grasses and not woods at all.  So if you’re simply looking for the hardest wood-like flooring material available, hardwoods may not be what you’re looking for.