The Janka wood hardness scale is the industry standard that carpenters and other professionals who use wood utilize to determine its durability.
The hardness scale will tell you which wood species are likely to withstand wear and tear and which ones will be easy to drill, nail, or saw.1
Crucial parts of a house like the floor should have the best wood in terms of hardness due to the constant stepping that will happen on the floor over time.
And because wood is a sustainable material, it’s a much better solution than fabricated flooring that uses petroleum or extensive chemical and process manufacturing to create.
Although these hard woods take time to grow, the carbon emissions they store during their life remain in the material, making it a better choice for flooring than vinyl.
The Janka wood hardness scale lists the hardness of wood species where the highest ranking makes up the hardest woods.
This guide outlines 113 domestic and foreign species of wood, with their hardness scale rating.
Janka Wood Hardness Scale Chart
The wood hardness scale is determined by measuring the force required to embed a .444-inch steel ball up to half of its diameter in a piece of wood.
There are many factors that you can use to determine the hardness of a wood species but the Janka hardness scale provides a general guide.
Please note that even the wood species with the highest ratings on the Janka scale can still be dented and scratched by heavy and sharp objects. Therefore, use the scale to guide you on the most durable woods but be keen on maintenance to avoid early wear and tear.
Janka Wood Scale
|Hardness Rating (Janka)
|Atlantic White Cedar (Image: Internet Archive Book Images/NCSU Libraries15)
|Butternut (Image: Internet Archive Book Images/NCSU Libraries16)
|Norfolk Island Pine
Atlantic White Cedar
Red Oak Trunk
Birch Tree Trunk
Beech Tree Trunk
Honey Locust Trunk
Understanding the Janka Wood Hardness Chart
Janka hardness ratings are determined by the Janka hardness test,9 which was invented in 1906 by an Australian wood researcher Gabriel Janka. However, the American Society for Testing and Materials (ASTM) standardized the scale in 1927 and started using it to measure the hardness of flooring wood species.3
The scale is used to determine how durable different wood species are based on their density. While the hardness ratings will help you pick the best flooring materials for your home, it does not guarantee lifelong durability. Like every other material, even the hardest wood will succumb to dents and scratches if not well maintained.
The Janka hardness chart, therefore, acts as a guide to help you pick the wood that is less likely to dent or scratch under good maintenance. It helps you know which type of wood to use in rooms with a lot of traffic to avoid denting and scratching.
How Does the Janka Hardness Test Work?
Janka hardness test uses a 2″ x 2″ x 6″ piece of wood and a 0.444″ steel ball.6 The steel ball is then pressed halfway into the piece of wood, and the force used for that determines the hardness of the wood.
The hardness is measured in pounds per square inch, and the higher the rating, the harder the wood. The highest rating on the Janka wood scale is 4000.3
A Few Janka Hardness Rating Facts
Here are some interesting facts about the hardness rating of Janka wood.
1. The Higher the Rating, The Harder the Wood
One thing to note about the Janka hardness scale is that the wood species with the highest number on the rating will be the hardest. If you are looking for the best wood to use for your floors, select among the high ratings on the scale because they make up the hardest materials.
However, there are many other factors that will determine the best wood for woodworking based on its usability. If you pick a wood species that ranks really low on the scale, it might not be as durable and strong enough for a floor with heavy traffic.
2. The Grain of the Wood Matters
The grain of the wood used in testing will be significant for the results. The results will vary based on the grain of wood used. The standard is the flat grain, whose results will reflect on the Janka hardness scale.
Vertical wood grain results do not appear on the scale, but that is also tested when doing the Janka hardness test on different wood species. Other tests include the ends and the sides, but the results are also excluded from the hardness scale because they are different. Therefore, the results on the Janka wood hardness scale are from the flat grain of the wood being tested.
3. There Are Different Tests on Wood, But Not All of It Makes It to the Scale
Wood undergoes different hardness tests when calculating its hardness rating. However, not all of the results make it to the Janka hardness scale.
A typical Janka wood hardness scale will have the results from the flat grain of the wood specimen. However, other grains will be tested, too, to compare the results.
The flat grain is used for the standardization of the results and to have accurate readings across all wood specimens. However, other wood hardness tests could use the sides, ends, and other grains to determine the hardness of the wood. Janka hardness scale is the standard used in woodworking because of the accurate results and standard way of calculating the hardness.
4. Ratings Start From 0 to 4000
The lowest score on the Janka hardness scale is 0, but there is no wood with that rating. However, the closer the number is to 0, the softer and easy to dent the wood will be. On the other hand, Janka’s hardness scale’s highest score is 4000.
All woods have a hardness that is between 0 and 4000, with 4000 being the hardest and strongest wood. Even though a piece of wood with a 4000 rating on the scale would be extremely strong, durable, and scratch-resistant, it might not be suitable for flooring. That is because the density also makes it hard to use with a saw or drill.3
5. The Janka Ratings Are Stated Differently Depending on the Country
Janka rating can be confusing to most people because it is stated differently in different countries. For example, Sweden uses kilograms of force and Australia uses Newtons. In the USA, the unit used to state Janka ratings is pound-force.7,10
It is important to understand the different units to be able to interpret the scale from different countries. Even so, all the rating units represent the same level of hardness, which means the scale is standard across the board. You just need to know how to convert the numbers to your desired units to understand the scale.
6. A “Good” Janka Rating Will Depend on the Use of the Case
There are multiple factors that play a role in the appearance and durability of your floors. Even if the harder the wood, the better the scratch resistance, how you take care of it also matters. You could use the hardest wood on the scale and still have a dented and scratched floor years later.
Too much traffic, poor maintenance, and lack of protection from heavy objects will dent and disfigure your floors after a while. However, the harness scale guides you on the wood to use for flooring.
For example, Balsa wood is not a good choice for floors because it has a rating of 100, which is way too low. Anything above 1000, however, would do great on floors.
7. Wood Pricing Rarely Depends on the Janka Hardness Scale
It would make sense to price wood based on how high or low it ranks on the Janka hardness scale, but that is not how it works. Even though that is a factor to consider when selling wood, there are other factors, like availability, with a bigger impact on the price.
If a certain wood species is readily available, it will be more affordable than other rare wood species. That is irrespective of how hard the wood is. Common hardwoods retailing at very affordable prices compared to other rare softwoods.
Therefore, it is possible to buy good flooring wood species without breaking the bank. With the factors discussed above, you can see that any reasonable hardness rating above 1000 will make a good flooring material with the right care.
8. Janka Hardness Chart Represents the Density of Wood
High-density wood is strong and stiff, which makes it highly durable and perfect for flooring and other such uses. Everyone is looking for wood with a high density to ensure that their floors last for a long time. The Janka hardness chart can also help you determine the density of wood because the woods with a high rating also have a high density.
If you want wood that will be easy to use and provide durable floors for your home, anywhere between hard and moderately hard wood ratings is where to look. Medium hardness will be the same as medium density, which is workable if you take good care of your floors.
9. Engineered Hardwoods Are Not on the Janka Hardwood Hardness Scale
Engineered hardwoods are made of a plywood core and a layer of thin hardwood flooring at the top.12 It is better in terms of affordability and sometimes durability, but it does not appear on the Janka hardwood hardness scale.
It looks almost the same as real hardwood, but the composition is not the same. That could pose a problem with moisture, strength, and stability. While it is affordable and easier to get, the real hardwoods on the Janka scale are the best to use for polished and durable hardwood floors.
10. The Janka Hardness Scale Is Not Enough To Gauge the Effectiveness of Flooring Wood
While the Janka scale gives you good guidance on the wood to choose from, it should not be the only criteria you use to pick wood for your flooring. The scale just indicates the hardness or density of the wood and does not necessarily mean that the wood will be perfect for every home.
A home with less traffic could do well with wood with medium hardness, but making that choice depends on the wood’s availability and the installation cost. Consider the ease of working on the wood and how you want to use it before making any purchases. However, it is good to know how a certain wood species ranks on the Janka wood hardness scale before buying.
Woodworking Wood Hardness Chart
|Southern Yellow Pine (Longleaf) (Image37)
|Black Cherry (Image38)
|Red Oak (Northern)
Southern Yellow Pine (Longleaf)
Why Is Wood Categorized by Hardness?
The main reason why wood is categorized by hardness is to determine how easily the tree species will dent or scratch. Another important reason for doing that is to know whether a certain tree species will be easy to saw and nail.
With the Janka hardness scale, you can gauge the durability of wood through how it ranks on the scale. The higher the rating, the higher the hardness. That also means that woods at the top of the rank will be harder to saw and drill.
The Best Wood on the Wood Flooring Hardness Scale To Use
1. Maple Janka Hardness
There are different types of maple trees that people use for flooring. The main categories are the hard and the soft maples. For the hard one, its Janka scale rating is 1450. That is a good rating for a durable and easy-to-work-with flooring material.
The softer maple, the red maple, has a rating of 950 on the Janka hardness scale. That is also not so bad, but it is much softer and more susceptible to dents and scratches compared to hard maple. However, red maple would be easier to saw and nail. There are various species of hard maple, and all of them have the same rating on the scale.
2. Oak Janka Hardness
Oak trees range between 1200 to 1400 on the Janka hardness scale. The softest oak tree, red oak, has a rating of 1220, while the hardest one has 1360. The English brown oak is the hardest of the oaks, with other oaks like white oak and Quarter Sawn White coming pretty close.
Oak trees and considered strong trees that have a pretty long lifespan.11 Therefore, all of them make good flooring materials, even the softer ones like Curly Oak and Spalted Oak. Red oak is the industry benchmark for wood hardness.
3. Mahogany Janka Hardness
Mahogany is a popular hardwood with a variety of species that have different hardness ratings.13 The hardest mahogany is the Santos Mahogany, with a hardness of 2200 lbf. It is, therefore, one of the best materials to use for the flooring to achieve high durability.
African Mahogany falls in the middle with a rating of 1100, while Genuine Mahogany is the softest at 800 lbf. Besides flooring, mahogany is also popular with high-end furniture due to the hardness and high density of the wood. However, mahogany is quite pricey because of its limited supply.
4. Teak Janka Hardness
Teak is a perfect material for flooring because of its hardness and shrinkage coefficient. It has a Janka rating of 1080, which is slightly higher than the English Oak. It has a tight wood grain and a high natural oil content, which makes it survive harsh weather conditions.
However, teak is likely to crack when the temperature and humidity change, which makes oak a much better option here. Also, teak is a rare tree species and does not grow in the US, making it very hard to access even though the demand is pretty high.
5. Walnut Janka Hardness
The average walnut tree hardness on the Janka scale is 1010. However, the Mayan walnut tree species is among the hardest flooring materials, with a rating of 1400. It makes good wood for flooring because of the moderate hardness but needs more care and protection than oaks and maples.
It is, therefore, not ideal for floors with high traffic as it will wear out pretty fast. However, the Black walnut is rot-resistant, which is an excellent quality for wood used in flooring. If you want to build your house in a place that is moist and humid, it could be a great choice for your floors.
6. Bamboo Janka Hardness
Strand woven bamboo is one of the hardest flooring materials available in the market today. It ranges between 3400 and 4000 on the Janka scale. That makes it highly durable and perfect for floors with high traffic.
Different bamboo trees could have different Janka scale ratings because of factors like harvest time, compression rate, and material density. However, it will still rank very highly on the scale. Bamboo is usually 2-3 times harder than most of the hardwoods listed in the table above. That makes it an excellent building material for floors that last for decades.
7. Eucalyptus Janka Hardness
Like bamboo, eucalyptus is also a very hard wood that works well on floors. The Janka scale chart above lists it at 1400, but some species have had a much higher rating than that. The same factors that affect the hardness of different bamboo trees will affect the eucalyptus tree.
If you come across eucalyptus as an option for floor materials, you should pick it and pay the required amount for a durable floor. Good floor installers will know the best species to use, which makes it easy for you to have the most durable floor available.
8. Ash Janka Hardness
Ash has a hardness rating of 1320, higher than most other hardwoods. There are different ash wood species, like swamp ash and white ash, but they all have the same rating. The only difference is the black ash, which is much softer, with a rating of 850 lbf.
Even so, all ash tree species make excellent floors that could remain stable and appealing for a long time. The trick to keeping your ash wood floor looking great is to avoid placing heavy objects on it and keep off any sharp things. That way, you can enjoy a beautiful floor with very high durability.
9. Birch Janka Hardness
Birch tree species have a medium range of hardness. They rank from 1200 – 1260, which is better than most other flooring options. The good thing with medium hardness is that the material will be highly durable and still easy to manipulate.
You can easily shape the wood into the designs you want because it is not hard to drill or nail. The Flame and Burl Birch are among the hardest species of the tree, while the Masur Birch is the softest.8 Birch trees are popular flooring materials in the US because of the abovementioned features.
10. Rosewood Janka Hardness
Rosewood trees are among the strongest and hardest flooring material options. The softest species has a Janka rating of 1780, which is way higher than almost all popular flooring materials.
The Madagascar Rosewood is the hardest, with a rating of 2720, which is higher than all maples and oaks. Therefore, using Rosewood as your flooring material guarantees ultimate durability and scratch resistance.
While those may be excellent qualities, it is important to note that such wood will be harder to nail and saw. You should therefore have an experienced floor installer help you with the flooring and ensure they have the right tools for the job.
How Do They Measure Wood Hardness Levels?
Wood hardness levels are measured through the Janka wood hardness test. It involves a small piece of wood as a specimen and a steel ball pressed against the wood. The test will determine how much force is required to force the steel ball into the piece of wood until halfway through its diameter.
Then the result will be represented in different units depending on the country the test is done. In the US, the unit for Janka hardness test results is pounds-force.
Exotic vs Domestic Wood Hardness Scale
Domestic hardwoods are those found in North America. They include Oaks, Maples, American Cherry, and Birch trees. Exotic trees are from the rest of the world and are mostly found in tropical areas. These trees include the Australian Cypress, Brazilian Walnut, and Purple Heart.
Domestic hardwoods have a traditional appearance, while exotic ones tend to have a modern look. The color change in exotic hardwoods is more rapid than in domestic ones. Also, the exotic hardwood trees will be harder than domestic ones.5
However, both types of wood make good flooring materials. That is because the hardness and density of wood are not the only factors to consider when selecting flooring materials. Regarding carbon footprint, domestic hardwoods have a lower impact on the environment compared to imported exotic hardwoods.
The Janka wood hardness scale helps guide installers and building owners on the best wood materials to use for floors. However, it is just one of the many factors that you should consider when selecting flooring materials.
It is advisable to choose domestic hardwoods for your floors as they have a lower carbon footprint and work as effectively as any other hardwoods. They can also grow in various areas, which makes it easy for carbon sequestering through dense forests of hardwoods.
Use the Janka wood hardness scale above to pick the best materials for your next flooring project.
Frequently Asked Questions About Wood Hardness Scale
What Is the Hardest Wood Used for Flooring in the US?
Read More About Wood Hardness Scale
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