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Hardness |
RELATIVE
HARDNESS OF SELECTED WOOD
FLOORING SPECIES
(Ranked
by Janka hardness rating)
The
Janka (or side) hardness test measures the force required to embed a
.444 - inch steel wall to half its diameter in wood. It is one of
the best measurements of the ability of a wood species to withstand
denting and wear. By the same token, it is also a good indicator
of how hard or easy a species is to saw or nail. Northern Red Oak,
for example, has a Janka hardness rating of 1290. Brazilian
Cherry, with a rating of 2350, is nearly twice as hard. If you're
accustomed to working with Red Oak and decide to tackle a job with
Brazilian Cherry, you can expect it to be much harder to cut and nail.
.Source:
Hardness ratings for most species taken from Wood Handbook: Wood as an
Engineering Material (Agriculture Handbook 72, Forest Product
Laboratory, Forest Service U.S. Department of Agriculture; revised
1987). Except for Australian Cypress, Wenge, African Padauk,
Merbau and Santos Mahogany, which were provided by International
Hardwood Flooring; Heart Pine by Mountain Lumber and Mesquite by
Mesquite Products of Texas.
Douglas
Fir rating is an average of ratings for coast, Interior West and
Interior North species.
RELATIVE
STABILITY OF SELECTED WOOD
FLOORING SPECIES
(Ranked
by dimensional
change coefficient)
The
numbers in the chart reflect the dimensional change coefficient for the
various species, measured as tangential shrinkage or swelling within
normal moisture content limits of 6 - 14 percent. Tangential
change values will normally reflect changes in plainsawn wood.
Quartersawn wood will usually be more dimensionally stable than
plainsawn.
The dimensional change coefficient can be used to calculate expected
shrinkage or swelling. Simply multiply the change in moisture
content by the change coefficient, than multiply by the width of the
board.
Example: A mesquite (change coefficient - .00129) board 5 inches wide
experiences a moisture content change from 6 to 9 percent - a change of
3 percentage points.
(Calculation:
3 x .00129 = .00387 x 5 = .019 inches).
In actual practice, however, change would be diminished in a complete
floor, as the boards' proximity to each other tends to restrain
movement. The chart is best used for comparison.
* Although some tropical woods such as Australian Cypress, Brazilian
Cherry, Merbau and Wenge appear in this chart to have excellent moisture
stability compared to domestic oak, actual installations of many of
these woods have demonstrated significant movement in use. To
avoid problems later, extra care should be taken to inform potential
users of these tendencies prior to purchase.
.Source:
stability ratings taken from Wood Handbook: Wood as an Engineering
Material (Agriculture Handbook 72, Forest Products Laboratory, Forest
Service, U.S. Department of Agriculture; revised 1987).
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| Brazilian
Cherry |
2350 |
| Mesquite |
2345 |
| Santos
Mahogany |
2200 |
| Merbau |
1925 |
| Jarrah |
1910 |
| Purpleheart |
1860 |
| Hickory/Pecan |
1820 |
| African
Padauk |
1725 |
| Wenge |
1630 |
| Hard
Maple |
1450 |
| Australian
Cypress |
1375 |
| White Oak |
1360 |
| Ash |
1320 |
| American
Beech |
1300 |
| Red Oak
(Northern) |
1290 |
| Yellow
Birch |
1260 |
| Heart
Pine |
1225 |
| Black
Walnut |
1010 |
| Teak |
1000 |
| Black
Cherry |
950 |
| Southern
Yellow Pine (Longleaf) |
870 |
| Southern
Yellow Pine (Loblolly & Shortleaf) |
690 |
| Douglas
Fir |
660 |
Stability
| American
Beech |
.00431 |
| True
Hickory |
.00411 |
| Jarrah |
.00396 |
| Red
Oak |
.00369 |
| White
Oak |
.00365 |
| Hard
Maple |
.00353 |
| Yellow
Birch |
.00338 |
| Pecan |
.00315 |
| Brazilian
Cherry* |
.00300 |
| White
Ash |
.00274 |
| Black
Walnut |
.00274 |
| Douglas
Fir |
.00267 |
| Southern
Yellow Pine |
.00265 |
| Heart
Pine |
.00263 |
| Black
Cherry |
.00248 |
| Santos
Mahogany |
.00238 |
| Purpleheart |
.00212 |
| Wenge* |
.00201 |
| Teak |
.00186 |
| Padauk |
.00180 |
| Australian
Cypress* |
.00162 |
| Merbau* |
.00158 |
| Mesquite |
.00129
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