Infrastructure
Explained: Wood Is Making A Comeback In Construction
- Wood, popular construction material of the past, had been largely abandoned for brick, steel, and concrete. But it is now making a return.
A wooden building under construction
Wood is one of the oldest construction materials, known for its exceptional properties — strength, low weight, easy machinability, and, most importantly, its renewability and limited carbon footprint.
It was the most popular material until the mid-eighteenth-to-nineteenth century and has been abandoned for brick, steel, and concrete, with the fear of flammability being one of the biggest reasons for its abandonment.
But also, in an industrialised world, large-scale construction projects were centralised and executed with much less skilled labour, which made steel and concrete the more favourable materials compared to wood.
Apart from places in North America and northern Europe, and rural regions where construction is still primitive, wood has maintained its status but is not used a lot around much of the world.
Of course, wood has continued to be a part of interiors, decor, and furniture, but as a construction material, it has seen a re-emergence in the twenty-first century, becoming popular among eccentric architects and developers.
There is already a healthy competition in multi-storied wooden construction, such as to build sky-scrapers in the twentieth century to achieve unprecedented heights. The tallest of complete wooden buildings is Mjøstårnet in Brumunddal, Norway, at 85.4 metres. It surpassed Hoho in Vienna, which stood at 84 metres.
But Tokyo is taking the race to new heights — a 350 metre-tall wooden skyscraper is planned in the centre of Tokyo by the consortium of Nikken Sekkei and Sumitomo Forestry, which are among the biggest Japanese architects and wood processors respectively.
Reinforced cement concrete is among the biggest contributors to carbon emissions — approximately 35 per cent of all carbon emissions come from it. Wooden construction can be a climate-change solution in this backdrop.
While climate-change action is looking at some of the most expensive carbon-capture technologies, inexpensive agroforestry can capture carbon to achieve climate targets. These can be sustainably funded by construction and related wood/pulp industries.
Wood has exceptional physical properties — it is lightweight and has a very high strength-to-weight ratio, seismic resilience, insulation, and a more predictable behaviour compared to concrete and steel.
Most importantly, new technical developments in wood engineering, nano-engineering of wood, and wood adhesives and clamping will change the landscape of wood use in construction.
As an easily machinable material, it can be pre-fabricated at an industrial scale, and being light, it can save transportation costs. Wood-based construction at a similar scale of concrete is 10 times faster to execute, saving both money and time.
Building with wood is already economical, on a par with concrete, but to achieve a competitive edge over alternative construction materials, wooden construction needs scaling, such as with larger projects involving stadiums, larger multi-storied buildings, and housing projects.
Current wooden construction is heavily dependent on a few species of spruce, pine, and fir, supply markets for which are mostly dominated by North America and northern European regions.
These wood types are long, straight, and uniform in composition and have a high strength-to-weight ratio, which makes them suitable for use in constructing tall buildings. There are areas in India suitable for such species, but they are under conservation zones where wood cannot be logged.
India has a small but growing market for wood-based construction, and most of the demand comes from the hospitality sector for cottages and summer houses, and very few residential and commercial buildings, which are often one- or two-storied buildings, not exceeding four floors.
“There is a growing interest for wooden construction in India, but it will materialise only in the long-term since the Indian market is very sensitive when it comes to housing, and shifting from concrete to wood as the main building material will need a lot of convincing and market awareness,” says Darshan Patil, Sales and Marketing Manager, Forestree India Pvt, a Trichy- based firm that specialises in all wood and wood-based products and wooden construction.
“Current consumption of wood, timber, and even pulp-based products are growing rapidly in India, and India is heavily dependent on imports, mainly from African, southeast Asian, and north American countries, with several restrictions on local wood sourcing. The recent ban on imports from Myanmar makes our industries dependent on very few supply links, due to which the scope for liberalising local agroforestry and diversifying agroforestry species to reduce imports and improve India’s green cover is under-realised,” Patil says.
Speaking on localising wood sources, he says, “Most of the Indian timber species are hard wood, which are not very viable for construction as they grow slow and are expensive and un-easy to work with on construction sites, unlike SPF which are soft wood that can be cut into any form and shape effortlessly. Hence, promoting the cultivation of SPF in appropriate geographies with India, aided by suitable agroforestry policies, can make wooden construction more affordable and more appealing."
Patil says the lack of adoption of wood construction is not just limited to market awareness and sensitivity about housing. India has not yet standardised codes and procedures for wood construction, and existing codes and practices are under-developed and haphazardly spread across multiple code books, making it harder to follow.
Indian builders often refer to Chinese building standards.
Speaking from his experience of participating in various wooden house workshops, expos, and conferences, he says, “Canadian wood companies, which are setting foot in India in a large way, are way ahead when it comes to wood construction technologies and wood skills, due to their previous experience at home with wood, and investment in skills and wood research."
Patil says Indian construction faces skilled labour shortage, and when it comes to wooden construction, the skilled labour factor is much more crucial since wood requires more precision-oriented tools and skills, and labour in India is not experienced in handling precision tools. This is another major challenge to scaling wood.
Wood construction industry, for now, is very picky when it comes to wood species. Even for the most viable wood, only 30 to 50 per cent of wood from tree trunks is usable, where ends and slightly bent parts have to be tapered, leading to more than half of the wood being rendered useless.
But new innovations in forestry, wood engineering, clamping technology, and nano-engineering of wood promises to enhance the usability of wood, as they can alter wood growth, influencing wood density and shape, and wood nano structure and behaviour under various conditions of load.
Another promising development is in the genetic modification of several timber and pulp species, which can alter wood composition at a much more fundamental level, enhancing favourable traits in a species.
Several genetically modified species are already awaiting de-regulation to go commercial. Some species like GM Eucalyptus are already de-regulated and produce 30-50 per cent more pulp mass than usual unmodified species. Genetically modified species for timber are also less controversial and easily acceptable to the general public compared to GM food since they are not used for consumption.
GM wood is also important in view of the growing stringent environmentalism against climate change. Several species and forest regions that are integral to today’s timber supply chain are likely to receive protection from logging.
New innovations and genetically modified species should be made immune to such vulnerable supply chains.
Wooden construction is only catching speed now. It is still in the early stages, awaiting some technological advances that can alter the landscape of construction and city skylines in the future.
