Janka Hardness

Floor Sanding Sydney

The great advantage of solid wooden floors is their durability. They resist wear and tear and will last for decades. And when they do show signs of superficial surface wear they can be re-sanded to make them look as good as new. It is not uncommon to have floors re-sanded after about 10 years of use.

Hardness of Floor Timber

The wood produced by different species of trees will vary in strength, hardness and appearance. These factors can also vary with processing and staining.

The hardness of wood is determined with the Janka test. This measures the pressure required to press a 0.444 inch steel ball half way into a wooden surface (a depth of 0.222 inches). The result gives the Janka number. In Australia the Janka number is given in kilo Newtons kN.

Timber suitable for flooring will require a Janka hardness of about 6kN or greater. Woods with Janka numbers of up to 12kN are not uncommon. A few timbers rate up to 16kN.

Past a certain point the Janka number is not really important. Most timbers sold for flooring are hardwoods of sufficient durability, and under normal conditions they will last for decades, with occasional surface re-sanding. 

Floor timber can be chosen mainly for colour, pattern and appearance rather than durability, because almost all timber flooring is sufficiently durable.

Floor Sanders Sydney

Talk to us if you have any questions about having your floors re-sanded, or for advice on re-staining or lime wash.