A century after Gaudí’s death, contemporary architects and engineers are using cutting-edge technology to complete what he started, extending the spirit of experimentation that defined his work—by Ruth Lang
The path to completion for one of the world’s most ambitious architectural projects has not been an easy one. When visionary Catalan architect Antoni Gaudí took over Barcelona’s Sagrada Família in 1883 following his predecessor’s resignation, he undertook a wholesale redesign of the basilica. Gaudí always knew the project would outlast him—a stance he reiterated with the acknowledgement that “my client is not in a hurry”. Yet in the 43 years he worked on it before his death, he completed only around 20 per cent of the overall building.
The team who took over initially relied on the detailed plans Gaudí had completed for the remainder of the scheme, yet these were lost to a fire in the basilica’s workshop in July 1936, started by members of the Iberian Anarchist Federation (FAI) who equated the Catholic Church with the Nationalists during the Spanish Civil War. The subsequent realisation has thus always been a combination of careful detective work, calculation and experimentation. Based on the models, drawings, photographs and notes salvaged from the fire, teams of architects, contractors and engineers spent the following decades working to execute the designs in accordance with Gaudí’s original intent. The construction’s height rivals Montjuïc, the hill overlooking Barcelona. But it was deliberately conceived to be one metre shorter, as Gaudí believed human creations should not surpass those of God. This meant it became the world’s tallest church on 30 October 2025. As the project moves towards a significant construction milestone in 2026, the ongoing challenge lies in faithfully interpreting Gaudí’s vision while completing one of the most complex architectural undertakings in history.
Professor Mark Burry AO, the founding director of Swinburne University’s Smart Cities Research Institute, has been instrumental in this mission since his initial visit to the basilica in 1977, where by chance he met two of Gaudí’s collaborators. As Burry recalls, he came with two questions: “Where was the authority to complete the building coming from when so little of the building had actually been completed? And how, precisely, were instructions given to the master masons charged with actually building so complex a construction?”
All answers lay in untangling the secrets Gaudí had set out decades before. This act of translation is not merely filling in the gaps left in the wake of the destruction of his plans but a creative act in its
own right, which has demanded huge innovations in human, digital and material expertise.
From the 1980s onwards, Burry oversaw researchers and engineers leading this detective work. The challenge is more than merely replicating Gaudí’s characteristic ‘edible architecture’ (his organic, almost melting forms that seem shaped by natural forces rather than human geometry) as the work demands deference to the structural ingenuity of his designs.
The design was born from a strict geometry—akin to the mathematical principles that drive the growth of leaves, snowflakes and other natural forms—which underpins the overall architecture
for the basilica. Burry’s team undertook a comprehensive digital transcription of the surviving fragments of the scale models previously created, employing mathematical analysis and structural prototyping to better understand how this could be translated into full-scale construction details through reverse engineering.
In a 2023 ABC News profile on the completion of La Sagrada Família, British-Australian consulting engineer Professor Tristram Carfrae explained that “every surface of the church is what we call technically a ruled surface, it’s a hyperboloid, a hyperbolic paraboloid, a cylinder, a spiral, all of which can be made out of straight lines”. In other words, even the most complex curves in the structure can be built from straight beams or panels.
Burry compares the process of identifying and documenting these geometric forms to cartography rather than architecture, mapping and extrapolating the geometries to understand how the design comes together.
The team moved from analogue tools to computerised software in the 1990s. But only with the advent of parametric design tools
commonly used in aeronautical engineering could they work fast enough to meet completion deadlines. Such digital innovation enabled the team to model Gaudí’s intricate geometry, but translating this into buildable reality remained a challenge, as the scheme exceeded the limits of traditional construction.
Purists may find the use of contemporary materials and technologies in the completion of the structure to be a compromise, when in fact this continues a lineage of technical innovation Gaudí embraced in the earlier phases.
Under his instruction, the pinnacles of the bell towers were constructed in the relatively new material of reinforced concrete. The team is comfortable extending that logic: 3D printing is used to prototype design strategies, while computerised numerical control (CNC) has accelerated construction tenfold compared with traditional methods. The same technology has enabled them to remove excess materials from the panels, reducing weight without compromising strength—an approach that led naturally to the lightweight fibre-composite units used in constructing the Evangelist towers in 2023.
Rather than using the labour-intensive masonry methods which characterised the lower sections of the basilica, taking up much space on site and demanding skills now dying out in the construction sector, current phases employ robots within fabrication processes that take place remotely, while post tensioned stone panels are brought to site and assembled like Lego blocks. To withstand earthquakes, conventional construction would require a steel or reinforced concrete structure clad with stone, but the chosen approach halves the weight while achieving the same seismic resilience, enabling the original foundations and crypt to be retained where larger footings would have obliterated them.
True to form, having solved the structural challenge, even this part of the construction has not been a smooth process. The supply of sandstone that marked the initial works from nearby Montjuïc was found to be increasingly fragile, and the quarry was forced to close in the 1970s. Thus, reclamation strategies to locate and salvage similar materials from buildings facing demolition were initiated while a search for a stone of comparable quality, colour and structural capacity was underway. As a result, the stone from which Barcelona’s icon is currently being constructed comes from Brinscall Quarry in Lancashire in the UK.
The more technically progressive aspects are complemented by a team of craftspeople who still employ historical methods for hand-finishing and hand-splitting the face of the stone, lending it a human touch which demands a re-translation of the digital back to the analogue. Alongside them, artisans create the stained glass windows and figurative sculptural details decorating the church, as part of a program which will be ongoing for decades to come.
In the centenary year of Gaudí’s death—and with the basilica’s Tower of Jesus Christ, completed in February 2026, now crowning the Barcelona skyline—the project has clearly demanded innovation from the outset. But it has also required a much more humane practice of listening to craftspeople, understanding natural geometries, and learning from a century-old model hand-built with wire and plaster of Paris. Without these traditional and technically advanced aspects working in tandem, bringing Gaudí’s vision to life would never have been possible.