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What is the Timber Flooring Janka Hardness Rating?

Timber floors have been very common in many places, especially Australia, since European building construction first began. You can find them in both houses and public buildings and make up an important part of the building’s structure. While timber floors can provide a basic walking area within a building and create an attractive feature in homes when the homeowner polishes them, it is also very easy to damage them.

Factors to consider before buying timber flooring

While wood flooring looks quite attractive there are some common daily occurrences that can easily diminish this beauty. These occurrences include the following:

  • Extensive traffic in a small section of the floor causing a “worn” look in only that area
  • Lack of care when moving furniture
  • Chair loads that fail to provide proper load bearing for the floor
  • Stiletto heels crossing the surface—can cause damage even to hard timber

While the above incidents are certainly considerations before choosing wood flooring, the main reason people choose this type of floor is appearance. Additionally there are factors that influence appearance such as colour, width of the board and even the finish of the individual wood an individual or contractor uses.

Janka test for hardness

Testing the hardness of any wood has no relationship to the wood’s ease when working with various tools. Instead it is a measure of how well the wood resists indentation. The figures from the Janka test are used to determine the hardness of any piece of timber.

In order to check the hardness of wood using the Janka hardness rating test a steel ball that measures 11.18 mm in diameter is pressed into the test specimen until it reaches half the diameter of the ball. Some of the available Janka figures are only based on a small sampling, and as such are not appropriate for those who need to make fine distinctions between various types of wood. The two primary sets of figures are for green wood and seasoned wood. Sometimes green wood in a particular species shows a lower hardness than mature timber in the very same species; however, this is not consistent with all species of wood.

The Janka wood ratings are generally as follows:

  • Soft/Hard
  • Moderately Hard/Very Hard

Other types of flooring options

While timber is a very common type of flooring, there are other types as well such as engineered flooring, laminate flooring and bamboo. In most cases engineered flooring has a face of solid timber that is approximately 3mm thick on the upper surface that is already exposed. You can purchase bamboo flooring as laminated flooring or as strand woven flooring. The former is classified as hard while the latter falls into the very hard category.

Understanding the test results

The results of the Janka testing process are stated in accordance with the measurements in various countries thus leading to confusion. For instance, in the United States the measurement shows in pounds; in Sweden it appears in kilograms; and in Australia it appears in either newtons or kilonewtons. This can become confusing for someone who does not understand the different measurements or are uncertain which unit of measure was used in the testing results.

The direction of the grain in wood has a significant bearing on the hardness. This means if the testing results from side hardness (measure in the direction of the centre of the tree), the result will be similar to that obtained from an angle than is tangent to the rings of the tree. The most common purpose of a Janka hardness rating test is to determine whether a particular species of wood is suitable as a material for flooring.


When considering whether to install wood flooring, it’s important to keep the hardness factor in mind. Some woods do not hold up well when they are installed in high traffic areas or areas that sustain damage from the movement of high heels or improper movement of furniture. All of these factors are important to consider before choosing wood flooring or make the decision to choose other types of flooring such as laminate or bamboo.

Janka testing determines the hardness of an individual piece of wood, and this in turn tells a potential buyer whether that type of wood is suitable for his purposes. While the results are not likely of great importance to someone who is hiring a contractor, the buyer does need to inform the contractor of the circumstances surrounding the area where he is installing the floor so he can choose the proper wood hardness for that area. 

Looking for timber flooring for your home? Lifewood's range of Jarrah flooring in Perth is some of the hardest timber on the market. Why not ask company owner, Mark Hutchison a question on Google+ now!

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