The time for timber in the built environment is now
The time for timber in the built environment is now
The student-centred biophilic interior of the University of Pretoria's Future Africa campus designed by Earthworld Architects.
With the built environment responsible for about 40% of global energy-related carbon emissions, sustainable forestry and engineered timber have the unique potential to decarbonise the built environment quickly and at scale while supporting urban development, rural economies and innovation.
A report by Arup, Rethinking Timber Buildings: Seven Perspectives on the Use of Timber in Building Design and Construction, said around two billion square metres of new buildings were required globally every year between 2019 and 2025 to keep up with urban development and population growth. The impact of urbanisation has seen businesses and homeowners, architects, engineering professionals and sustainability experts looking for science-based greener solutions. The obvious answer is wood.
“South Africa is ripe for scaling up the use of timber in construction beyond roof trusses. Although there is a long-standing timber frame and log homes building industry, most people perceive wood as rudimentary or weak and reserved for tool sheds, dog kennels and other “cheap” nondurable uses”, comments Roy Southey, executive director of Sawmilling South Africa (SSA).
Southey says there is significant opportunity for innovation, localisation and employment creation for mass timber structures. Constructing homes and buildings with timber is feasible because architects, construction engineers, and manufacturers of wood products employ digital design, building information modelling (BIM), and modern tools to engineer wood into beautiful yet functional and safe structures.
“Using timber in buildings creates an opportunity to reduce the country’s carbon footprint and provide new opportunities for manufacturing, skills development and the unemployed. For threason, promoting timber is part of the Commercial Forestry Industry Masterplan, which outlines plans to encourage sector growth, investment, job creation and competitiveness”, says Southey.
Earthworld Architects made innovative use of plywood and laminated timber in the design of the University of Pretoria's Future Africa campus.
The Sustainability Factor
In South Africa, wood for structural timber comes from years of carefully bred hybrid and cloned seeds and seedlings forming sustainably managed pine and eucalyptus commercial timber plantations. “It is a myth that timber production causes deforestation”, Southey explains.
“Deforestation is the removal of trees or clearing of indigenous forests for commercial development, housing, firewood or agriculture without replanting. Sustainable forestry ensures trees are planted, grown, harvested and replanted according to strict environmental policies, international certification and local legislation”.
According to Forestry South Africa, less than 10% of the country’s total plantation area of 1.2 million hectares is harvested annually. Felled trees are replaced in the same year by saplings, often at a ratio of 2:1. This means there is a constant supply of trees for productive purposes for years to come.
South Africa’s plantations also remove carbon dioxide from our atmosphere during their seven to 20 years rotations. Southey adds, “All timber products – whether a wooden pole, a plank, plywood, engineered board products like MDF and cross-laminated timber (CLT) – keep the carbon locked up”.
The forestry value chain contributes R69 billion annually to the South African economy, with sawmilling supporting approximately 30,000 people in predominantly rural communities.
The Conservation FactorHe CONseRVATION FACTOR
South Africa is not tree-rich, unlike Sweden, Canada, and some other African countries. The country has only half a million hectares of indigenous forests, roughly 0.4% of the total land area.
“If it weren’t for the commercial planting of trees from the early 1900s, the country’s indigenous forests would have been eliminated many years ago for our fuel, furniture and fibre needs”, notes Southey. However, a forestry landscape is far more complex and diverse than rows of planted monoculture trees. Only 70% of forestry-owned land in South Africa is planted to trees, with a significant unplanted proportion reserved for biodiversity conservation, natural corridors, riverine habitats, indigenous flora and wetlands.
The Cost Factor
Sawmilling South Africa (SSA), the South African Wood Preservers Association (SAWPA), the Department of Trade, Industry and Competition (the dtic) and other value-chain partners have hosted a series of webinars on the properties, applications, engineering possibilities and the value of timber in the built environment.
Timber-based buildings can be pre-manufactured at an off-site facility, requiring semi-to unskilled labour to assemble on-site. “From manufacturing to assembly, using timber will benefit foresters, communities and small and medium businesses and the greater supply chain”, says Braam de Villiers, owner of Earthworld Architects.
Timber structures may cost about 10% more to build, but they can be constructed in half the time. A recent master’s study by Fanie van der Westhuyzen at Stellenbosch University compared the cost of developing a multi-storey mass timber building with a reinforced concrete structure in South Africa.
Van der Westhuyzen found that an eight-storey timber building would cost R115.691,000, whereas the reinforced concrete alternative would cost R105.118,000. However, the timber construction would take 21 weeks instead of 42 weeks, with considerable cost savings.
The Lucky Bread coffee shop showcases the versatile planes and curves of timber construction and Earthworld Architects designs.
The Quality Factor
The forestry value chain contributes R69 billion annually to the South African economy, with sawmilling supporting approximately 30,000 people in predominantly rural communities.
A timber-building culture will upskill workers and create new jobs by developing a circular bioeconomy. Modern renovation and timber prefabrication methods require different skill sets and knowledge bases while developing and improving traditional manufacturing processes.
South Africa has top-quality structural pine softwoods and eucalyptus hardwoods. “The country is one of only two countries in the world where the quality of structural timber is assured by compulsory, continuous strength testing at a grading facility”, ” says Prof Brand Wessels from the Department of Forest and Wood Science at Stellenbosch University.
“The South African National Standards (SANS) timber quality standards ensure that our timber structures remain amongst the safest in the world”.
South Africa has top-quality structural pine softwoods and eucalyptus hardwoods. The country is one of only two countries in the world where the quality of structural timber is assured by compulsory, continuous strength testing at a grading facility.
The Biophilic Factor
The term biophilia, stemming from the Greek roots meaning ‘love of life’, was coined in the 1950s by German social psychologist Erich Fromm. It came into use in the 1980s when American biologist Edward Wilson pioneered a new school of thought focused on the need to bring humans back in contact with nature.
Wood and natural materials deliver a degree of well-being, happiness and comfort that other materials can’t match. Biophilic design is a component of many building certification systems, including LEED, WELL, BREEAM and the Living Building Challenge.
A research report by Terrapin Bright Green on *The Economics of Biophilia (2023) found that user health and well-being rarely comprise the conventional cost/value engineering model for building and development projects that emphasise the initial investment cost.
“With the growing interest in and adoption of environmental, social, and governance (ESG) metrics and impact investing (investments with a broader purpose beyond profits alone), investment parameters and value engineering will hopefully soon incorporate post-construction impacts on occupant/user health and well-being, along with other fundamental factors supporting a resilient and healthy society".
The Floating Timber Box home designed by Gauteng-based Earthworld Architects.
The Timber Factor
Sawmilling South Africa (SSA), the South African Wood Preservers Association (SAWPA), the Department of Trade, Industry and Competition (the dtic) and other value-chain partners have hosted a series of webinars on the properties, applications, engineering possibilities and the value of timber in the built environment. Look out for the next Talking Timber online seminar.
