Floor Sanding and Polishing Sydney

Timber Hardness

Floor Sanding and Polishing Sydney

Different species of wood will have different properties. There is also a certain amount of variation within a species. One important factor here is the hardness of the timber. Some timbers are soft, like Balsa or pine. Other timber are very hard, like Teak or Jarrah. The hardness of timber is a major factor when we look at how long a timber floor will last, and how much it resists scratching.

The hardness of timber is measured on the Janka scale. Basically, the higher the Janka number the harder the wood. But this can be misleading as there are other factors at work.

The Janka measurement system take a hard ball bearing and pushes it into the timber’s surface. The harder timbers require more pressure to push the metal ball into the wood surface, so they receive a higher Janka number. A Janka number of 4-8 is a good option for a floor. Some very hard timbers have a janka rating between 8 and 12.

But the Janka rating, the hardness, is not the only consideration here. For one thing we may not want to walk on a super hard floor because a very hard surface (think of concrete) is tough on the feet. We tend to feel that a slightly softer floor feels better. So a moderately hard floor with a Janka between 4 -8 is often the best option.

Another issue is that hardness and surface durability are not always the same. This is especially obvious with bamboo. Bamboo is often very hard on the Janka scale, even as the top surface is prone to scratching. Bamboo is simultaneously hard enough to last for decades, put prone to superficial surface scratching. Janka wasn’t designed to test bamboo, hence the confusing result. But some timber suffers the same problem, at least to a lesser extent. The timber is hard enough to last, but gets scratched more than we might expect.

Another factor is the pre-treatment of the wood. Floors can be given protective coating that effectively make their surface harder, or they might be processed in other ways to increase their hardness. This is why pine, which is relatively soft, actually make a decent floor material if given a protective coating.

Some people are confused by the classification of ‘hardwoods’ and ‘softwoods’, expecting a hardwood timber to be literally harder. But the hardwood/softwood distinction refers to the grain of the timber and not the actual hardness of the material. Technically Balsa wood is a type of hardwood, even though it is physically soft. Though generally hardwoods are physically hard.

Floor Sanding and Polishing Sydney

We insist on quality timber for floors, which lasts for decades, and which can be re-sanded and polished several times to restore its original appearance.

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