Copyright © 1998 TMT All rights
reserved.
Revised:April 28, 2008.
Ekki wood is naturally durable. This means that EKKI hardwood, without the application of chemical preservatives, resists biological attack from a wide variety of sources, including marine borers, due to the combination of its hardness and its natural constituents, including high silica content.
EKKI hardwood ranks with the most naturally durable timber types in the world.
Wood types are broadly categorized in five classes according to their natural resistance to biological attack in temperate climates. Table 4 below lists some well-known wood species in each class, class I being the most durable and class V being the least durable. "YEARS" indicates the number of years that these wood types (excluding their sapwood) may be in direct contact with unprepared, moist and bacteria laden soils without serious degradation. Of course, if the wood is used or installed in a manner that reduces or eliminates exposure to biological attack, service lives may be much longer. Source: Timber Institute of Delft in the Netherlands and the Wood Institute of Amsterdam.
|
CLASS |
YEARS |
TYPICAL SPECIES IN THIS CLASS |
|
I |
25+ |
EKKI, Basralocus, some types of Eucalyptus, Yellow Cedar, Jarah, Greenheart |
|
II |
15-25 |
Western Red Cedar, California Redwood, white Oak |
|
III |
10-15 |
Some types of Pine, Douglas Fir, Hemlocks |
|
IV |
10-5 |
Some types of Fir species, Hemlock, Red Oak and some types of Maple |
|
V |
>5 |
Alder, Poplar, Linden, Birch, some types of Maples |
Table 4, Comparative durability of several wood species
NOTE:
It should be noted that the above classifications require the exclusion of sapwood. It is typical of commercial softwood lumber that sapwood is not excluded. Therefore for softwood types the classifications noted above may be optimistic. EKKI logs have a very thin layer of sapwood. This sapwood is always removed and does not occur in our EKKI hardwood products.
