Wood took the stage in November at the 2025 Green Building Council South Africa (GBCSA) in Cape Town, where industry experts addressed delegates in a timber-focused workshop on the theme Timber transformed: Building our future with nature's most sustainable material.

The workshop unpacked timber's potential, from its proven environmental and structural benefits to the practical realities of cost, certification, and design. The speakers used South African case studies to explain how architects and builders can reimagine present and future spaces with timber.

The speakers and their topics were:

• Ferdinand Hassan: Change starts with you: Timber and the carbon challenge
• Braam de Villiers: Navigating the 4th industrial revolution: How the revolution will impact the sustainability of the planet
• Jamie Smily: Design for disassembly: Circular buildings with CLT and Glulam
• Damien Mocke: Raise the roof: Timber floors for green CBD densification
• Carmia Paterson: Mass timber construction in South Africa: Cost and potential use
• Christo van der Hoven: Four years of MTT and thoughts for the future
• Gerard Busse: Understanding timber certification in the South African context: Is my timber genuinely sustainably sourced?
• Siviwe Mbinda: Uplifting communities through timber.

The workshop began with a presentation by Ferdinand Senam Hassan, a PhD Candidate and Assistant Lecturer at the University of Pretoria. He spoke about the timber and carbon challenge, arguing that, with global building sector emissions continuing to rise and progress on reducing operational emissions insufficient, the sector must make tangible efforts to reduce embodied carbon emissions.

Ferdinand emphasised that timber is not a niche alternative, but a critical component in rethinking how the building industry addresses carbon reduction. Timber, in various forms, was presented as a structural lever capable of transforming the industry's ethos.

Digital design

The second presentation was delivered by Braam de Villiers, Director at Earthworld Architects. Braam examined how digitalisation is reshaping the construction industry and what this means for its future.

He noted how tools such as Building Information Modelling (BIM), parametric design, and CNC manufacturing are materially altering design and production workflows. These technologies have moved engineered timber from a craft-oriented material to one capable of industrial precision.

Digital modelling, automated fabrication, and integrated design-to-production pipelines now enable the conceptualising, prototyping, and manufacturing of complex timber structures with a level of accuracy that would have been impossible a decade ago. CNC fabrication reduces tolerances and complexity during manufacturing, enabling assembly by teams with varying skill levels. This shift has consequences beyond efficiency.

Braam emphasised that in the South African context, digital workflows can expand labour participation rather than displace it. Digital timber construction can localise value creation, linking design, fabrication, and assembly in ways that generate employment and skills development, rather than reproducing the job displacement narratives often associated with 4IR.

Circularity with timber

The third presenter, Jamie Smily, Managing Director at XLAM, discussed a recurring theme at the GBCSA Convention - circularity.

Jamie made a strong case that timber, particularly cross-laminated timber (CLT) and glued-laminated timber (glulam), enables the creation of building components that can be removed, reused, and reconfigured with significantly less degradation than conventional materials.

He highlighted emerging case studies where structural timber retains high value even after deconstruction. The underlying argument was that timber enables a shift from "end of life" to "next life", moving the industry closer to circular construction principles.

Green CBD densification

Urban densification may require us to build up rather than out. According to Damien Mocke, Technical Specialist at Smec, this means we need lighter, faster, and cleaner construction systems.

Damien's presentation confronted a central question for Cape Town's future: will the city continue to thicken its skyline with concrete and steel, or adopt lighter, cleaner construction systems capable of supporting real urban sustainability?

He positioned engineered timber not as an aesthetic choice but as a strategic material shift. Mass timber systems, such as CLT, glulam, and hybrid composite panels, offer high structural performance, require a fraction of the energy needed to manufacture steel or concrete, and store carbon rather than emit it.

Damien argued that mass timber delivers three decisive advantages for CBD densification: mass, speed, and value. Timber buildings weigh 50-75% less than their concrete counterparts, making rooftop additions feasible on structures that would otherwise require extensive foundation strengthening.

Off-site prefabrication reduces construction time, noise, labour intensity, and disruption to surrounding businesses. These conditions are critical in dense CBD environments. Faster programmes and reduced substructure work translate to improved project economics and earlier returns.

To demonstrate the potential of these principles, Damien introduced a case study reimagining a 60m ageing building in central Cape Town. The structure is a candidate for timber-led vertical expansion, using parametric modelling to test multiple overbuild scenarios.

The concept proposes self-supporting prefabricated rooms on the building's edges, four additional floors built from composite concrete–timber systems on an extended concrete core, and a striking curved glulam super-truss that anchors a rooftop amenity programme complete with restaurant, bar, and pool.

The proposal also includes a new timber-and-glass façade and planted balcony zones to reinforce the building's biophilic character. While detailed fire, acoustic, heritage, and structural assessments remain part of the feasibility process, the presentation emphasised that technical pathways already exist, backed by global precedents and ongoing local research.

Cost of mass timber construction

One of the aims of the timber workshop at the GBCSA was to directly confront misperceptions of timber, and Carmia Paterson's presentation tackled a critical issue: cost.

Carmia, a quantity surveyor and master's student, distilled three key findings from her research. First, for low-rise buildings, mass timber is already cost-competitive with conventional materials in South Africa, and in some cases, can deliver significant savings. The market data presented in the session showed little price difference between timber and traditional construction for comparable building types, countering the perception that timber incurs a cost premium.

Second, a persistent gap remains between industry perceptions and actual cost performance.

Many practitioners believe mass timber to be cheaper, faster to build, and inherently more sustainable. At the same time, they continue to cite maintenance requirements, limited technical skills, and uncertainty around scalability as barriers to adoption. These perceptions remain largely untested in the South African context, highlighting the need for more transparent cost information.

Finally, cost benchmarks for medium- and high-rise mass timber buildings remain underdeveloped, and systematic life-cycle cost comparisons with concrete and steel are still limited. Carmia said the structural timber industry must address these gaps if it wants to move beyond isolated projects and achieve broader market uptake.

Four years of MTT

Four years since its founding, Mass Timber Technologies (MTT), a producer of CLT and glulam, has continued to grow from strength to strength, with projects in South Africa and internationally that demonstrate the possibilities of timber construction.

Christo van der Hoven, Technical Director at MTT, said more needs to be done to ensure timber construction becomes mainstream. A central structural challenge facing the South African construction industry is the timing of design decision-making.

Using the McLeamy curve as a reference point, Christo argued that timber construction cannot reach its full potential if design development continues to follow conventional, late-stage workflows inherited from steel and concrete practice. The McLeamy curve illustrates that the ability to influence project outcomes—cost, performance, constructability—is highest in the early stages. In contrast, the cost of design changes increases sharply later in the process.

Mass timber, with its dependence on precise digital modelling, factory fabrication, and coordinated tolerances, amplifies this dynamic. If critical decisions on geometry, engineering strategies, and connection systems are deferred until late in the project, the material's advantages are diminished or lost altogether.

More design effort must shift to the front end of projects. Early integration of architects, engineers, fabricators, and contractors is not ancillary but fundamental to realising the efficiencies that digital timber systems offer. Without this shift, mass timber risks being constrained by workflows that were never designed to support it.

Project certification

Gerard Busse, Market Development Manager for the Forest Stewardship Council (FSC), addressed a practical but often poorly understood area of the timber value chain: how sustainability claims are verified.

Gerard outlined the core principles behind FSC certification and explained how practitioners can interpret and navigate the process. He emphasised that certification is not merely a label but a chain-of-custody system that requires every stage—from forest management through processing to final delivery—to meet defined environmental and social standards.

A significant portion of the session was dedicated to "project certification," a mechanism that allows construction projects to demonstrate that a defined portion of the timber they use is sourced from responsibly managed forests.

For designers and contractors working on buildings with mixed material supply chains, project certification offers a more flexible route to verifiable sustainability claims without requiring every supplier to hold full FSC certification.

Gerard also provided examples of FSC-certified timber being used across Africa, illustrating that certified supply chains are not limited to isolated pockets or premium markets.

These examples served to counter the assumption that certified timber is inaccessible or impractical in the South African context. Instead, certification is becoming an increasingly relevant tool for ensuring credibility in sustainability reporting, particularly as embodied carbon and responsible sourcing gain prominence in the construction sector.

Timber and communities

The final session brought the social dimension into focus. Siviwe Mbinda, Director at iThuba Innovation Hub in Langa, Cape Town, provided a powerful reminder of timber's potential to uplift communities.

He confronted an uncomfortable but necessary starting point: in many low-income South African communities, timber is not associated with innovation, architecture, or sustainability. It is associated with firewood, temporary shelters, and structural vulnerability.

This historical relationship shapes how communities view timber's legitimacy as a building material. Recent collaborative projects, however, are beginning to shift this perception.

Siviwe said external partners have introduced design and fabrication support that enables residents to build durable, well-designed timber structures, far removed from the improvised forms typically associated with informal settlements. The process delivers new building methods while allowing local residents to reinterpret what timber can be used for.

As community members gain confidence in designing and assembling higher-quality structures, they are actively transferring this knowledge to neighbouring areas, creating a diffusion effect that extends beyond the initial project sites.