Demystifying Timber Flooring Hardness

Hardness floor

Choosing a timber flooring option for your home or commercial space can be tricky. There are many aspects of the wood to consider. One of those aspects is the hardness of the timber. In this article, we demystify timber flooring hardness. Read on to find out how floorboard hardness is measured and why it’s important.

Choosing Timber Flooring

As the amount of variations in timber floorboards has grown, so has the likelihood of the timber degrading if not chosen or looked after properly. Timber floors can be sensitive to environmental elements, as well as damage and scratching from people and furniture. The frailty of this natural material is what makes it so precious and beautiful.

While this vulnerability of wood might be off-putting to some, there are several ways to ensure the finish of any polished timber floor remains in immaculate condition. These include avoiding the movement of furniture across the floors (particularly if they do not have the appropriate protectors), wearing stilettos and dragging chairs along the dining room floor. It’s also possible to ‘wear away’ floorboards if they’re in a high traffic area.

When renovating, building or restoring, many people focus on the appearance of their floors. Some choose solid timber flooring while others choose engineered timber. In many cases the primary consideration is what colour to use, the plank width and the direction that it’s laid. However, there is more to consider when selecting timber flooring. One important way to ensure your timber floors stand the test of time is to invest in a durable wood that can withstand things like stilettos and the soft dragging of chairs without much damage. The hardness of your timber floorboards can be the difference between damaged floors and floors that last you a lifetime.

What is the Janka Hardness Test?

One of the systems we use to understand the different hardness levels of timber is the Janka Hardness Test.

According to the Australasian Timber Flooring Association (ATFA), the Janka test is a standard test which measures the force in kilonewtons (kN) required to press a steel ball of 11.18 mm diameter into the timber until the ball has penetrated to half its diameter. Check out the diagram below for a better understanding.

Contrary to common belief that the hardness is based on how easy it is to work with various tools, the Janka test acknowledges that the hardness of wood is determined by its resistance to indentation. This is called an impact test. Species of timber will have a Janka hardness rating in kN. The higher the rating number, the harder the wood.

There is some dispute as to the usefulness of a Janka rating. Firstly, because it is not relevant to most timber flooring types on the market today. The test cannot be used on a veneer or wood thickness less than 6mm, however, a lot of floors these days are engineered timber, made from a set of thin layers. It also only analyses one aspect of the floor’s durability and does not taking into account scratch resistance, stability, longevity and repairability. Another limitation of the Janka test is that is does not account for hardness variations within a species. It is best to consider the Janka rating as just one consideration out of many when choosing your flooring.

Janka Hardness Test

The image below shows the Janka rating in kilonewtons of timber species that are popular for use in Australian floors. To find out more about each wood species check out our species profile series of articles.

Janka Hardness Test

Alternative Timber Flooring Hardness Rating

Due to the Janka rating systems limitations, other methods for ranking timber species hardness are sometimes used. ATFA prefers using a Very hard, Hard, Moderately hard and Soft flooring hardness rating system. They state that this guide has sufficient information for a flooring buyer to make a decision, without causing confusion.

Find a table of common timber species in their hardness categories below.

Timber Hardness Rating

Engineered Timber Flooring Hardness

With most non-solid timber flooring planks, the hardness of the top layer is regarded as the hardness of the product. In a limited number of products, the upper wood layer does not reach 3mm, and in these cases the core timber influences the overall hardness of the floor.

Choosing the Right Timber Flooring Hardness

There is no right or wrong choice of timber for flooring, but understanding the wood hardness will help the decision-making process. When choosing a timber for your floors, consider how much foot traffic and/or furniture moving the floor will have to endure. For example, a residential bedroom will not require the same floor hardness as a well-used community hall. Finishes and lacquers will not have any impact on the Janka hardness of the floorboards.

To find out more about the hardness of timber flooring or to discuss which timber species that is right for you, get in touch with our experienced team today.