Sustainable timber and engineered wood have the unrivalled potential to decarbonise the built environment quickly and at scale, while supporting urban development, rural economies and innovation.
The built environment is responsible for approximately 40% of global energy-related carbon emissions[i] and these are coming from two main sources: operational emissions from energy consumed for heating, cooling and power, and embodied emissions associated with the extraction, processing and manufacture of building materials[ii].
Increasingly, sustainability experts, architects and engineering professionals are looking to wood to provide a green bullet. “South Africa is ripe for scaling up the use of timber in construction,” says Roy Southey, executive director of Sawmilling South Africa
“Mass timber building is becoming more feasible through modern tools and digital design to transform an age-old material into modern functional structures.”
It also provides opportunities for manufacturing, skills development and employment, which is why the promotion of timber is part of the Commercial Forestry Masterplan, which outlines plans to encourage sector growth, invest in job creation, and competitiveness.
The green factor
There is a strong climate case for wood. Trees are known to be one of the solutions for mitigating climate change. It’s no different for commercial forestry, which achieves this in two ways: by growing trees, which absorb carbon dioxide, and by harvesting trees for their wood at the right time, with carbon being stored in harvested wood products.
Southey explains that in South Africa, wood for structural timber comes from sustainably cultivated pine or eucalyptus plantations.
Harvested trees are replaced by saplings, often at a ratio of 2:1, which take up more carbon dioxide than their older counterparts, perpetuating carbon sequestration, while carbon stored in wood products – whether a timber pole, a plank, plywood or cross-laminated timber – is locked up in those products.
The cost factor
Timber structures may cost about 10% more to build than brick and mortar, but they can be constructed in half the time because they can be pre-manufactured off-site.
A recent master’s study by Fanie van der Westhuyzen from the University of Stellenbosch – A development cost comparison between a multi-storey mass timber and reinforced concrete building in South Africa – showed that an eight-storey timber building would cost R115 691 000 as opposed to the reinforced concrete alternative at R105 118 000. But the timber construction would take 21 weeks as opposed to 42.
Versatile and lightweight, wood is ideal for modular volumetric prefabrication of low-income housing as well as larger homes and multi-storey buildings.
The local factor
South Africa has top quality structural wood. South Africa is one of two countries in the world where the quality of structural timber is assured by compulsory, continuous strength testing at the grading facility.
“The introduction of a new South African National Standards (SANS) timber quality standard will ensure that our timber structures remain amongst the safest in the world,” says Prof Brand Wessels from the Department of Forest and Wood Science at Stellenbosch University.
The happy factor
‘Biophilia’ asserts that as humans we inherently seek connections with nature. Weaving wood into design is believed to improve wellbeing, job satisfaction and productivity[iii], aspects that other materials can’t match.
All factors considered, wood brings something special but it can have a greater purpose – to reduce carbon emissions and provide us with durable built environments.
[i] Global Alliance for Buildings and Construction. 2020, Global Status Report For Buildings And Construction, 4.
[ii] Time for Timber, Wood Manifesto, 2021.