cedar deck

What is the Janka Scale? (Janka Hardness Rating)

Published On: February 12th, 2020

For those of us who can’t resist the look and feel of real wood, the Janka Scale can be a valuable tool. While composite and vinyl decking are leading in the decking industry because of quality, comfort and longevity, there are a few of us who will insist on wood when investing in a new deck.

The Janka scale should help you decide on what kind of wood will be used for your project. The Janka scale determines how hard wood is. This, in turn, helps to determine how durable and long-lasting the wood will be over the years. If you live in Canada, the weather will most definitely be a factor. Choosing a wood that is both strong and beautiful is a must.

janka scale

What is the Janka Scale?

So, what exactly is the Janka Scale? The Janka hardest scale gives each type of wood (tree) a score. The system is named after an Austrian man named Gabriel Janka. He worked in the forest industry for the US department of agriculture. In 1906 he was given the job of coming up with a way to measure the hardness of different woods. The result is a test that measures the force required to embed a 11.28 millimeter steel ball into the wood to half its diameter. Although the scale has been formalized over the years, the premise remains the same and is universally recognized.

While choosing a wood, a rating of 1000 or more is ideal for interior floor applications. While deciding on a type of wood to be used in decking is a different story. Weather will, of course, wreak havoc on your wood deck, so choosing a wood with a rating of more than 1000 is advisable.

Ipe (Brazilian Hardwood) has a rating of 3680, for instance. This wood will be long-lasting, indoor or out. It will, however, like all wood decks, need maintenance. Staining or waxing each year can help prolong the life of your investment, but Ipe, just like pressure treated wood, will grey out. Something to remember when choosing a hardwood decking product.

Cedar is popular in the decking industry because of its character and amazing smell. Cedar has a Janka rating of 900. 

Pressure treated wood is an economical choice in decking choices. Pressure treated lumber is typically made from southern pine or douglas fir, and both have Janka ratings in the 600’s.

If you are determined to use real wood to construct your new deck, take a look at the Janka Scale to help you make that decision. Keep in mind that harder woods do cost more than their softer counterparts and that all wood will deteriorate over time. With some yearly maintenance and the elbow grease and budget to go along with it, your hard wood deck will be beautiful for years to come.