Janka Hardness Ratings

Janka Hardness Ratings

The Janka hardness test measures the resistance of a type of wood to withstand denting and wear. It measures the force required to embed an 11.28 mm (0.444 in) steel ball into wood to half the ball’s diameter. This method leaves an indentation. A common use of Janka hardness ratings is to determine whether species are suitable for use as flooring.

The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the grain is said to be of “side hardness.” Testing the cut surface of a stump is called a test of “end hardness.”

The Janka Hardness test is done in accordance with ASTM D 1037-7 testing methods. Material stocks ranges from 1″ to 2″ thick. (Numbers are an average. Testing is done on samples; not flooring that is already in place.) There is a standard deviation, but these numbers are not published. Other factors affect how flooring performs: type of core (for engineered flooring), grain direction, thickness floor and finish.

The Janka Rating does not indicate how a wood floor will dent, if it will dent or what will cause the dents.  Dents caused by dragging heavy furniture, rolling chairs, high heel shoes and dogs nails are the most common causes of dents and all are excluded from the wood manufacturer’s warranty.

In my experience dog’s nails, especially large dogs, are the number one cause of dents. It may be possible to repair dents if the finish remains intact and is not fractured and the wood is not scratched. To prevent further damage install felt pads on the legs of all furniture (even couches because they slide), keep the felt pads clean by removing grit, hair and debris, use protective mats under rolling chairs, use doormats outside and small area rugs at entrances, trim the dog’s nails regularly and try to contain vigorous play to an outdoor or carpeted area.

Rolling chairs, chairs and furniture legs without felt pads, sliding the refrigerator in or out and moving furniture on a wood floor without proper protection usually results in dents. Again, if the finish doesn’t get scratched the dents may be repairable.

High heels concentrate a person’s weight on a small area (125 lb. person=approximately 2,000 lbs. per inch when taking a normal step). This type of force may dent and pit wood floors. High heels in good repair may not damage wood floors. High heels with missing tips subject the wood floor to a metal spike; this almost guarantees damage. If you want to protect your floors from possible damage, you may consider instituting a “no high heel” policy.

Janka Hardness Rating
(Highest to Lowest)

2350 – Brazilian Cherry
2345 – Mesquite
2200 – Santos Mahogany
1820 – Hickory
1820 – Pecan
1450 – Hard Maple
1360 – White Oak
1320 – Ash
1300 – American Beech
1290 – Red Oak(Northern)
1260 – Yellow Birch
1225 – Heart Pine
1010 – Black Walnut
1000 – Teak
950 – Black Cherry
870 – Southern Yellow Pine (long leaf)
690 – Southern Yellow Pine (short leaf)
660 – Douglas Fir
380 – White Pine


Thank you for visiting and come back often,
Linda Lockwood
Statewide Floor Covering Inspection Service