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Naturally Durable Hardwoods

By Brian Lotz, Managing Director,
Timber Holdings Ltd., Milwauke, Wisconsin

Batavia Bridge in New York, made of Ekki and Jarrah.

There is a growing trend in the golf course, landscape architectural, architectural and engineering design markets toward the specification of naturally durable hardwoods such as Jarrah, Ipe’, Ekki, Bonalim and Kwila.

Some of these species’ most common uses include bridges, walkways, shelter structures, docks and piers, terraces, site furniture, light and sign posts, and retaining and noise abatement walls.

The attraction is these species’ high strength properties, hardness and natural resistance to attack by chemicals, fungus, termite and marine borers, as well as their high fire ratings. All of these incredible benefits mean maintenance-free construction and long service life.

The following quote regarding the performance of Jarrah is from a letter to a New York lumber company from Raymond Jordan, City Engineer in Ventnor, New Jersey:

“Please be advised that this Jarrah test strip, consisting of approximately 300 square feet of Jarrah 2”x4” decking was installed more than thirteen years ago, in an entrance ramp to the Ventnor City Boardwalk. After thirteen years of heavy pedestrian, bicycle and maintenance vehicle traffic, a recent inspection by this office could not detect any signs of splitting, checking, rot or other deterioration. The Jarrah lumber has also withstood the effect of harsh winters, high salt air moisture, and sharp angular beach sand with no appreciable surface wear. The Jarrah lumber was installed as it was received, in its natural milled state with no preservation of any kind. Since installation, the Jarrah lumber has not received maintenance of any kind nor has any preservative been applied. At the time of our recent inspection, the Jarrah lumber appears not to have lost any of its structural integrity, surface quality or durability.

This boardwalk and theme park in Orlando, Florida utilizes Kiln-dried Jarrah decking material.

Specification of naturally durable hardwoods has also increased due to the mounting concerns of environmentalists and the EPA concerning the use of toxic chemical wood preservatives.

As with any construction material, each of the previously mentioned species of wood has different properties and performance characteristics. There is no one species of naturally durable hardwood that is perfect for every application.

Timber Holdings Ltd./TIMBATECH LTD., divisions of CECCO Trading Inc., a Milwaukee-based firm directed by Brian Lotz, have spent years providing expertise in naturally durable hardwood specification and engineering. A stocking importer and distributor handling all of the aforementioned species, Lotz notes that there is no one super wood. Specifiers must pay special attention to the individual characteristics of the species they are considering. The key to a successful project or fabrication is using the appropriate species for a given application.

As an example, Lotz references a 12’x110’ clear span-through truss bridge recently designed and built by Timber Holdings for the City of Batavia, New York. Ekki was used for the structural members because of its strength and availability in large sectional sizes. Jarrah was selected for use in the rails, ballisters, decking and light fixtures because of its superior esthetic appearance and stability because of kiln drying. It is important to note that kiln drying stabilizes a piece of wood to a moisture content equal to the moisture content of the air which surrounds it.

Other examples of installation of these species include:

The Boardwalk and Baseball Theme Park in Orlando, Florida: Kiln-dried Jarrah decking was installed on aluminum extrusions. This process required a timber that would remain very stable, as movement in the timber could cause the aluminum extrusions to distort.

Jarrah decking on the Atlantic City, New Jersey Boardwalk.

In Charleston Waterfront Park, South Carolina: Kiln-dried Ipe’ decking is to be installed on fresh cut Ipe’ stringers. The decking is dried to provide stability. The stringers can be fresh cut because of their larger sectional sizes.

At the Club Hotel Boardwalk, Wall Disney World, Orlando, Florida: Kiln-dried Jarrah is installed on fresh cut Ekki stringers.

Shedd Aquarium, Chicago, Illinois: Kiln-dried Jarrah is used in the coastal boardwalk and exhibit area, an interior but high-humidity environment. Ekki is again used for bridge stringers because of large sectional size availability.

189,000 square feet of Sound Barrier Wall, DuPage, Illinois: Kiln-dried Bonalim is used for prefabricated wood panel construction for strength, stability and cost. Ekki posts are used because of strength and dimensional requirements up to 8”x15”x40’ long.

This Jarrah bench, manufactured by the D.M. Braun Co., is made from reforested timber in Australia.

Ekki is imported only fresh cut with a moisture content of approximately 3540%. This is not a problem in large sectional sizes. Smaller section material, however, is more prone to movement, i.e., shrinkage, twisting and warping, and must be handled more carefully than kiln-dried material. Ekki also requires the use of a special fastening system of steel dowels to prevent excessive movement during drying in installation. Ekki’s advantages are its availability of large dimensions and very long lengths.

Ipe’ has very comparable properties to Ekki, though it is straighter-grained and less prone toward movement. Ipe’ is generally lower in price than Ekki, but is more limited in dimensional size and length. The advantage of Ipe’ is its availability as kiln-dried material in smaller sectional sizes.

Jarrah has somewhat lower strength properties than Ekki and Ipe’ and is not available in large sections. Jarrah has the advantage of being kiln-dried, more stable, easier to work, and incredibly beautiful. It can be used for both indoor and outdoor applications. Jarrah is also the product of one of tie most well-managed forests in the world.

Barlow Tyrie, makers of this bench, is one of the few companies to receive the Seal of Approval from the Friends of the Earth organization for using reharvested lumber.

Teak has similar properties to Jarrah but is not available in large sections. It is primarily used in furnishings, due to its cost and lack of availability. There also seems to be some debate concerning the use of Teak. Taken from virgin timber stands, harvesting Teak is considered a blow to the continuation of the species. If not properly monitored, teak taken from plantations, however, may have the same effect. Although the Teak used in numerous products may be certified as coming from a plantation, and therefore considered ethical to use, such is not always the case. The question isn’t whether or not the Teak is coming from a plantation, but whether or not that plantation has a replanting program in effect. If Teak is taken from a plantation that is not replanted, the end result is the same as if it were taken from natural stands. Simply put, the status of the Teak being from a plantation isn’t the issue; whether or not it’s being replanted is.

With the growing interest in naturally durable hardwoods, it is important to understand their individual advantages and limitations when writing specifications, whether it be a golf course bridge, sound barrier wall, boardwalk or other significant project.

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June 26, 2019, 12:00 pm PDT

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