Cost efficiency

Determining the true costs of a building material requires evaluating the product over its life cycle and taking into account its environmental as well as monetary costs. When considered over its lifetime - from harvest of raw materials through manufacturing, transportation, installation, use, maintenance and end-of-life options - wood performs better than concrete and steel in terms of embodied energy, pollution to air and water, and overall carbon footprint.

Whole Life Costing demonstrates that building with wood is cost-efficiency.

Life cycle of wood

Production phase

The extraction, production, processing and transportation of wood are dry processes, consuming much less energy, water, labour and environmental cost, compared to the production of fossil fuel-intensive materials in steel and concrete plants.

Experiences in Europe demonstrate that if off-site pre-fabrication is used, construction time can be reduced by as much as two-thirds, compared with other construction types. With accurate design and assembly, prefabricated timber construction requires less time, fewer heavy-duty equipments and labours, causing less material wastage and environmental impact.

In-use phase

The operation cost in which energy cost is predominant accounts for a large proportion during the whole life costing. Due to the energy efficiency and air tightness of wood buildings, the energy cost can be dramatically reduced.

Research in the UK shows that wood frame construction becomes even more cost-competitive when higher energy-efficiency building envelopes are required. The study also demonstrated that wood roofs can be cost-competitive with concrete roofs, as well as having better thermal, seismic and occupant comfort performance.

There is also the additional benefit of 2%~5% increase in living space, as the wood frame walls can achieve excellent insulation values with a substantially thinner cross-section than other materials. This is a significant cost advantage on the basis of liveable space, which is generally not taken into account in standard cost comparisons.

End-of-life phase

Wood products and elements can be reduced with optimized design and construction, reused and recycled with good maintenance, and recovered as a biomass fuel. Read more about 4R material here.

Cost-competitive world-wide

International comparisons show cost advantages for building with wood over concrete and steel for many types of residential and commercial buildings. These demonstrate the potential for cost savings in China from building with wood, recognizing that modern wood construction in China is new and full economies have yet to be realized.

One study, carried out in South Carolina, USA, showed wood frame houses saving 14 per cent in construction costs compared with identical steel frame houses.

A recent cost study comparing wood and concrete for the construction of a three-storey motel building in the United States demonstrates that using wood can achieve a saving of 7-9 per cent in material costs alone.

Experiences in Europe demonstrate that wood construction can cut costs substantially, depending on design and application. If off-site pre-fabrication is used, construction time can be reduced by as much as two-thirds, compared with other construction types.

Even in areas like Taiwan, where wood frame construction is still relatively new, it has been shown by local design professionals that wood construction can be cost-competitive with concrete buildings. Wood roofs were shown to be less expensive than concrete roofs.

As wood is a better thermal insulator than other structural materials, wood frame buildings reach the high insulation standards increasingly by governments world-wide more easily.

There is also the additional benefit of a two to five per cent increase in living space, as the wood frame walls can achieve excellent insulation values with a substantially thinner cross-section than other materials. This is a significant cost advantage on the basis of liveable space, which is generally not taken into account in standard cost comparisons.

Research in the United Kingdom shows that wood frame construction becomes even more cost-competitive when higher energy-efficiency building envelopes are required.

Cost-competitive in China

Although modern wood construction is new to China, with full cost savings yet to be realized, in-depth research shows that wood frame construction is competitive depending on its application.

For example, a cost comparison study was conducted in China looking at identical building designs constructed with different structural materials. The results showed the construction costs of wood frame houses without living space in the lofts were lower than for concrete or masonry. In particular, materials and cost savings could be made in the foundations. When living spaces were built into the lofts, the cost of wood frame could be higher. But when comparisons are made per square metre of living space, they still work out cheaper to build than comparable concrete houses.

The study also demonstrated that wood roofs can be cost-competitive with concrete roofs, as well as having better thermal, seismic and occupant comfort performance.

Wood construction costs are becoming even more competitive in China

Wood construction costs in China are continuing to decline in comparison with traditional construction. This is as a result of the introduction and revision of building codes and standards, more extensive training for design, construction and maintenance, more building experience, new building methodologies and larger scale construction.

Continuing cooperation between China and Europe and North Ameirica in code development, quality issues, cost-saving building techniques, training and skill development, and research will accelerate improvements in cost performance.

It is important that wood frame buildings are correctly and appropriately designed and constructed to achieve their full efficiency and cost-saving potential. On balance, any meaningful comparison of competitiveness must move beyond costs alone into a broader evaluation of all the major performance attributes, where wood construction outperforms traditional construction in many other respects.

While modern wood construction in China is very recent, there is evidence that the overall cost of wood buildings, when considered over the full life cycle, combined with superior performance relating to energy and the environment, seismic safety, and comfort, will provide better value for the developer and the homeowner in comparison with traditional construction systems.

Cost comparison
Cost comparison between wood
and concrete construction
for three-storey buildings in the USA
Wood frame apartment building, Canada
Wood frame apartment building
Canada
Light-weight wood frame storeys
Light-weight wood frame storeys
can be added to new or existing
multi-storey concrete buildings

 
European Wood (in China)
C412, Beijing Lufthansa Center
50 Liangmaqiao Road, Chaoyang District
Beijing, P.R. China 100125
T +86 10 6462 2066, F +86 10 6462 2067
info@europeanwood.org.cn
Sino-European Wood Center
Room 202, Engineering Department,
Taoliyuan Hou, Xuhui Campus of Jiaotong University,
No.655 Panyu Road, Xu Hui District, Shanghai
Tel/Fax:021-53098550
info@europeanwood.org.cn