Few infrastructure sectors demand the same level of reliability and long-term performance as water infrastructure. Reservoirs, for example, are expected to operate safely and effectively for decades. Therefore, new construction technologies are subjected to rigorous evaluation before they are widely adopted. As a result, even innovations offering clear technical and economic advantages can take 10 to 15 years to achieve mainstream acceptance.
Precast construction addresses many of the sector’s longstanding challenges by moving much of the construction process from site to a controlled factory environment. This significantly accelerates construction, improves quality and enhances programme certainty. It also strengthens health and safety by reducing work at height, minimising high-risk on-site operations and creating a more controlled construction process. Notably, these safety advantages are the primary reason many European and North American clients specify precast construction for their South African projects, where meeting stringent corporate health and safety standards is a fundamental project requirement.
Beyond its safety benefits, factory-controlled manufacturing improves quality control, reduces material wastage, enhances resource efficiency and shortens construction programmes. The resulting lower environmental footprint and improved lifecycle performance align closely with the growing emphasis South African municipalities are placing on sustainable, resilient infrastructure. This reflects broader policy objectives contained in the National Development Plan 2030, the National Water and Sanitation Master Plan and National Treasury’s Infrastructure Asset Management Delivery Framework. All of these promote infrastructure that delivers greater resource efficiency, improved lifecycle performance and enhanced long-term value for public investment.
Corestruc has successfully challenged conventional mindsets by demonstrating that precast post-tensioned concrete reservoirs are far more than an alternative construction method.
“They are a fully engineered, turnkey solution that has been validated through rigorous design, comprehensive testing and proven in-service performance,” says Willie de Jager, Managing Director of Corestruc. ‘By combining factory-controlled precast manufacturing with precision post-tensioning techniques, we have developed a reservoir system that delivers exceptional structural integrity, watertightness, construction certainty and long-term durability.”
These engineering advantages enable municipalities to deliver critical water infrastructure more quickly and predictably, reduce lifecycle maintenance requirements, minimise service interruptions and maximise long-term returns on infrastructure investment.
Accelerating water infrastructure at scale
Having already contributed approximately 600 ML of water storage capacity across South Africa through the delivery of precast post-tensioned reservoirs and precast roof structures for conventional reservoirs, Corestruc has established itself as the country’s leading specialist in precast concrete water infrastructure. The majority of this installed capacity comprises the company’s post-tensioned reservoir systems, reflecting the growing acceptance of this construction methodology.
“Our expanding project portfolio demonstrates that the system is not only technically proven but also capable of accelerating the delivery of critical water infrastructure at scale,” says De Jager. Certainly, a full order book and continued business expansion underscore growing market confidence as municipalities, water authorities and private sector clients increasingly recognise the value of faster, safer and more sustainable reservoir construction.
Specified during design engineering
When Corestruc first introduced its precast post-tensioned reservoir system, it was often engaged to recover projects where construction had fallen behind schedule or encountered significant delivery challenges. The system restored programme certainty while maintaining the required structural performance and watertightness. As confidence in the solution has grown and its performance has been demonstrated across an expanding portfolio of successful installations, its role has evolved considerably. Today, the technology is increasingly being specified from the outset by major municipalities. The City of Ekurhuleni, for example, has already completed seven precast post-tensioned reservoirs using the system, while the City of Tshwane has also adopted the technology for new reservoir construction. “This marks a clear shift from project recovery to proactive adoption, reflecting growing confidence in the system’s ability to deliver high-quality water infrastructure safely, efficiently and within programme in metropolitans,” De Jager says.
Engineering confidence through innovation
Although the construction industry has embraced innovation in many areas, the adoption of new materials and construction methods remains relatively slow. Research shows that global construction productivity improved by just 10% between 2000 and 2022, compared with 50% for the overall economy and 90% for manufacturing. The same research concludes that construction continues to lag other sectors in adopting new materials and methods, with material innovation progressing considerably more slowly than digital technologies.
As a family-owned business, Corestruc can pursue innovation with a long-term perspective. Close alignment between ownership and management enables faster decision-making, strategic consistency and sustained investment in technologies that may take years to achieve widespread industry acceptance.
“Larger companies often need to balance innovation with more complex governance and investment processes,” states De Jager. “We’ve been able to respond quickly to industry challenges, refine our technology through continuous improvement and remain focused on delivering practical engineering solutions that create lasting value for clients.”
Although the company has grown significantly, it has deliberately retained the values and culture of a family business. Its flat organisational structure encourages accountability, collaboration and ownership at every level, empowering employees to contribute ideas, solve problems and maintain the high standards of quality and service on which the company has built its reputation.
“Our success stems from this agile philosophy,” De Jager says. “Every design is subjected to rigorous verification. Furthermore, we always return to first principles, using hand calculations to validate the outputs generated by advanced structural analysis software.”
He adds that all designs undergo comprehensive internal engineering reviews, while first-of-their-kind systems are independently reviewed by external specialists to provide an additional level of technical assurance.
This commitment extends well beyond design. Corestruc delivers a fully integrated turnkey solution, taking responsibility for every stage of the project – from design, manufacture and transport through to construction, commissioning, and the provision of appropriate guarantees and professional indemnity cover.
The company also invests significant engineering expertise, time and capital in demonstrating the technical viability of its solutions before project award through detailed engineering proposals, design calculations and constructability assessments. While this represents a substantial upfront investment, it establishes confidence and builds lasting client relationships. As he notes, few companies are willing to make this level of investment when introducing an alternative construction system to the market.
“We apply the same engineering standards to ourselves that we expect from our clients,” says De Jager. “We believe every construction challenge has a solution, but we also recognise that precast concrete is not always the answer. Our objective is not to promote a particular construction method, but to deliver the solution that offers the best long-term technical, operational and economic outcome for each project.”
Putting performance to the test
In 2019, Corestruc constructed its first two precast post-tensioned concrete reservoirs: the inaugural installation at KwaMhlanga, followed by a second reservoir at Bundu for the Thembisile Hani Local Municipality.
Securing these projects required more than an innovative concept. The confidence of the client and professional team was earned through Corestruc’s engineering discipline, its commitment to fully validating every aspect of the design and construction methodology, and its proven track record in delivering complex precast concrete structures. Together, these factors provided the assurance needed to pioneer a new approach to reservoir construction.
“We were fortunate that Ceenex and the Thembisile Hani Local Municipality gave us the opportunity to demonstrate the technology,” recalls De Jager. “While our engineering design was based on rigorous analysis, there is no substitute for proving a new system under real operating conditions.”
Both reservoirs successfully demonstrated the structural integrity, watertightness and constructability of the system while providing valuable practical insights that enabled the construction methodology to be further refined. Early observations, including minor efflorescence associated with the timing of the post-tensioning process, informed improvements to construction sequencing and post-tensioning procedures. Just as importantly, measured structural behaviour closely matched predicted design performance, providing further validation of the engineering methodology.
These lessons were immediately applied to the Bundu reservoir. Through refined construction sequencing and greater overlap between floor, wall and roof activities, Corestruc and the main contractor, Mbako Projects & Trading, significantly accelerated project delivery without compromising quality. The close collaboration between the project teams demonstrated not only the speed at which the precast post-tensioned system could be constructed, but also the value of meticulous planning, coordination and disciplined execution. “This collaborative approach has since been carried forward to subsequent projects, enabling further refinement of the construction methodology and consistently delivering efficient, high-quality outcomes,” he says.
The success of these pioneering installations laid the foundation for broader industry acceptance of the technology. This was particularly significant given that the Bundu reservoir formed part of the largest infrastructure project ever undertaken by the municipality, where long-term performance and durability were critical requirements. The completed reservoir was subsequently recognised in the Department of Water and Sanitation’s Blue Drop assessment, providing independent acknowledgement of the quality and performance of the infrastructure.
“The lessons learned from these early projects have since been incorporated into Corestruc’s standard design and construction practices, resulting in a mature, proven system,” he says.
Proven results. Continuous improvement.
Compared with conventional construction methods, the Corestruc system consistently delivers construction time savings of more than 50%. This efficiency has been demonstrated repeatedly on site, enabling the company to expand its market share while delivering measurable value through faster project delivery, reduced site costs and greater programme certainty. The strength of this approach is reflected in a robust order book and a growing portfolio of projects that consistently demonstrate superior cost-effectiveness.
Seven years after its first installation, the system has evolved from an innovative concept into a mature, field-proven construction solution. Every project provides opportunities to refine the design, optimise construction methodologies and improve efficiency. Continuous engineering improvement remains central to Corestruc’s philosophy because the company believes reservoir construction can always be safer, faster and more economical.
“The cheapest solution at tender stage isn’t always the most economical solution over the life of the asset,” says De Jager. “Our job is to help them make infrastructure decisions that will still stand up twenty or thirty years from now.”
