Are you in the process of purchasing wood for your next project? If so, it's important to select a type of wood that is durable and sure to last. The Janka Hardness Scale provides an efficient and reliable way to measure the ability of various types of woods to resist denting and wear when subjected to direct pressure. In this blog post, we will provide information on how this scale works as well as some tips for selecting the right type of wood using this system.
What Is the Janka Hardness Scale?
The Janka Hardness Scale is a system used to distinguish the relative hardness of a type of wood. It measures how much energy it takes, in pounds of force, to push a 0.444-inch steel ball into the wood to a depth of half an inch. Developed by Gabriel Janka in 1906, this scale has often been used as the industry standard for determining a wood's strength and durability in flooring. By using this system, buyers can use data to make informed decisions when selecting a wood sample. The hardwoods used most often are compared in terms of their Janka hardness rating, making it easier for consumers to decide which species is best for their needs.
Why Is Wood Hardness Important?
Harder woods will be more resistant to damage from wear and tear and will last longer, making them ideal for high-traffic places such as offices or retail shops. Softer woods are more susceptible to cracking, chipping, and damage during installation or typical everyday usage. Hence, hardness is significant since it may affect the longevity of hardwood boards, the amount of care and upkeep necessary, and how often the pieces of wood would need to be fixed or replaced. Moreover, the rating indicates how well the wood will resist damage caused by, nailing, cleaning, cutting, or drilling.
But, the Janka scale is not absolute, and it's important to remember that all forms of hardwood are fairly sturdy and long-lasting, which is why they're so popular with both residential and commercial clientele. And there are other ways to make the wood more resistant to scratching, which includes choosing the right finish such as tung oil. Hardness is one aspect to consider in the decision-making process, but it is far from being the only one.
How Is Hardness Measured Using the Janka Hardness Test?
The Janka Hardness test determines how much power is needed to embed a 0.444-inch steel ball halfway into a wooden board. By measuring this level of penetration, an accurate rating of the wood's hardness can be established in pounds-force (lbf). For example, Cherry wood has a Janka rating of 995 lbf, which implies that embedding the steel ball into the Cherry wood board required 995 pounds of force.
The Janka grade solely takes into account the hardness of the wood's face, not its edges or sides. This is mostly due to the fact that any pressure exerted to the timber during the installation procedure or during everyday usage will be applied to its face rather than its sides.
Understanding the Janka Ratings
A “good” Janka rating typically falls between 1000-3400. Wood with a higher rating is usually tougher and will stand up better to wear and tear, making it more suitable for high traffic areas. These include species such as Teak, Ash, Black Walnut, Larch, Red Oak, and Cumaru. Yet, there are additional factors to consider, such as humidity and foot traffic. For places that experience a lot of activity every day, like a workplace or a house with pets and children, it is best to choose a hardwood flooring with a high Janka rating. A lower rating is more than acceptable if the project incorporates a low-traffic location, such as a home library or home office.
A List of Wood Species from Hardest
- Brazilian cherry: 2350
- Mesquite: 2354
- Santos mahogany: 2200
- Merbau: 1925
- Purpleheart: 1860
- Hickory/ Pecan: 1820
- African padauk: 1725
- Wenge: 1630
- Hard maple: 1450
- White oak: 1360
- Ash: 1320
- Red oak: 1920
- Yellow birch: 1260
- Teak: 1000
- Black cherry: 950
- Southern yellow pine: 870 (1)
When selecting a wood based on durability, the Janka Hardness Scale is an excellent tool to use. How long your wood lasts depends greatly on its quality. The Janka Hardness Scale is a reliable way of testing the hardness of various woods to ensure that your materials are going to stand the test of time and last for many years. Buying quality, harder woods with higher ratings can save you time and money in the long run!
(1) Janka hardness scale. Superior Flooring. (2021, May 17). Retrieved March 10, 2023, from https://www.superiorflooring.ca/janka-hardness-scale/