Thermally-modified US hardwoods hold immense potential in the region as they not only exhibit the particular strengths of tropical hardwoods but also address environmental issues, says Roderick Wiles* of American Hardwood Export Council (AHEC).

01 May 2013

WHILE timber-clad buildings, decking, external wooden structures and wooden windows are the norm in many temperate climates, the trend towards using timber in these applications has been spreading further afield, including to the Middle East.

The Gulf has been importing significant volumes of tropical hardwood species and pressure- or chemically-treated softwood species that offer high performance in external applications. However, growing environmental awareness and stricter environmental regulations is forcing developers to look for timber from sources that have a proven record of sustainable management and low environmental impact.

Now, the process of thermal modification (also known as heat treatment) is able to provide temperate hardwood species with the requisite durability and resistance to decay that was, traditionally, only offered by tropical hardwoods. Whilst the concept is not a new one, thermal modification today is an industrial process, using painstakingly developed technology and it truly represents a new opportunity for American hardwoods.

Thermally-modified hardwoods

The thermal modification process, a clean and energy-efficient technology, uses high heat in a controlled atmosphere to improve both the dimensional stability and the decay resistance of wood by permanently altering its chemical and physical properties. By processing wood produced from America’s well-managed hardwood forests, thermally-modified US hardwoods provides an affordable and environment-friendly alternative to certain hardwoods that might be illegally harvested from endangered tropical rainforests.

The thermal modification process limits the ability of the wood to absorb moisture, so the product is more dimensionally stable and less prone to cup, warp and twist with changes in relative humidity. This increase in dimensional stability significantly extends the service life of applied finishes, reducing maintenance costs. The process also removes those nutrients in wood that would otherwise provide a food source for insects and wood-destroying fungi. As a result, the end products do not contain any toxic chemicals to improve longevity and performance.

Opportunities

Thermal modification opens up tremendous opportunities for manufacturers of wood products. The improved moisture resistance and dimensional stability of thermally-modified hardwoods make them an excellent option for wood flooring in spaces where solid wood flooring has traditionally been ruled out for reasons such as contact with water. Whilst engineered wood floors have been substituted in many of these areas, strip or plank flooring made from heat-treated hardwood lumber may be a solution to growing the available market for solid wood flooring.

There is also an opportunity for furniture manufacturers to produce wooden outdoor furniture made from thermally-modified hardwoods and offer it as an alternative to traditional species, such as teak.

In principle, heat-treated hardwood furniture could be made from lower-cost species, such as ash, red oak, tulipwood and soft maple. While this lower-material cost furniture might not take market share away from teak, it could win significant market share from metal and plastic furniture.

Heat-treated hardwoods also offer the possibility to produce more specialised wood products for those consumers looking for something unique in their homes. For instance, heat-treated wood has been used to replace tiles on a shower floor. In Europe, heat-treated wood has also been commonly used in spas for sauna benches because of its durability and low heat transfer. Homes with decks, balconies and patios are also potential spaces for heat-treated hardwoods. Composite decking products tend to be commonly specified, although, treated softwoods or cedar are also used. Heat-treated hardwoods have the potential to replace both, particularly for those building on the waterfront.

The thermal modification process also sequesters carbon within the wood, giving the end product a rich brown colour. The appearance and uniform coloration rival that of many tropical hardwood species and its colour alone may be enough to win over end-users, as has been the case with numerous furniture manufacturers around the world who are just discovering this material for the first time.

Green credentials

While the use of heat and, therefore, energy consumption may draw criticism from environmentalists, the end product does indeed deliver on the environmental claims it makes.

In a comparison between heat-treated lumber and chemically-treated lumber, a recent life cycle assessment conducted in Europe found that the former had about the same carbon impact on the environment as the latter, primarily because thermal modification relies on heat. However, heat-treated lumber is ‘greener’ than its chemically-treated counterpart because of the lack of chemicals used. Furthermore, in the case of American hardwoods, thermally-modified lumber can also be positively differentiated in the marketplace due to the long history of good forest governance and management practices in the US hardwood industry. Thermally-modified American hardwoods may also be the first truly green lumber resource that performs better and costs less than alternative products developed to replace wood.

Market potential

The potential for thermally-modified American hardwoods is certainly promising, both in established markets as well as in developing ones. The somewhat limited availability may be a constraining factor for the immediate future, but this is changing very quickly, as producers adopt the technology across the US, Canada and also in Europe and Asia.

As the product becomes better known, it is anticipated that its potential as an alternative option in exterior applications or in wet environments will be exploited widely. Its consistent rich brown colour, its dimensional stability, resistance to decay and its environmental credentials all point to it being one of the most exciting new products the wood industry has been able to offer in recent years.

* Roderick Wiles is director for Africa, Middle East, India and Oceania of American Hardwood Export Council (AHEC).

• Hot demand seen for heat-treated wood
• Masa offers tips on protecting timber

Tags

Regional News UAE Focus Events Diary of events Legally Bound Cladding & Facades Timber & Plywood Weather & Waterproofing Geosynthetics Saudi Arabia Tenders

Gulf Construction is the undisputed leading trade journal for the building and construction industries of Saudi Arabia and the other Gulf states. The magazine provides editorial coverage on a wide range of topics which are of interest to industry professionals. In addition, regular features highlight technological developments within specific industry fields. Launched 40 years ago, the magazine has established an enviable reputation as an authoritative, respected journal with unmatched coverage of the Gulf region. Gulf Construction is essential reading for anyone with a serious interest in the region’s building and construction industry.