UHPC Technology for the Crown of the World’s Tallest Church

Few structures are as renowned worldwide as the Sagrada Família in Barcelona (officially: Basílica i Temple Expiatori de la Sagrada Família). For more than 140 years, this landmark has been regarded as one of the most extraordinary architectural projects in the world. With the completion of the Jesus Christ Tower, the basilica shaped by Antoni Gaudí now reaches a height of 172.5 m (566 ft), making it the tallest church in the world. On June 10, 2026, the tower was officially inaugurated and blessed by Pope Leo XIV—exactly 100 years after the death of Antoni Gaudí, who assumed responsibility for the project in 1883, one year after construction began, and subsequently transformed its design in a fundamental way.

With Dyckerhoff NANODUR® Compound 5941, Dyckerhoff also contributed to this landmark architectural achievement. Used as a binder premix for the Ultra-High Performance Concrete (UHPC) of the crowning cross of the Torre de Jesucrist, the material played a key role in one of the most distinctive elements of the Sagrada Família. The cross, approximately 17 m (56 ft) high and 13.5 m (44 ft) wide, forms the pinnacle of the tower and was completed on February 20, 2026. NANODUR® Compound 5941 was specifically developed for precast applications. In the aggregate mix, crushed stone was replaced with rounded quartz sand to improve workability and achieve an optimized UHPC formulation with a compressive strength of 150–165 N/mm² (approximately 21,800–23,900 psi).

The contract for the construction of the crowning cross was awarded to Josef Gartner GmbH of Gundelfingen, Bavaria. Sudholt-Wasemann GmbH of Herzebrock-Clarholz served as the technical partner for the project. The company was responsible for manufacturing the entire formwork system, installing all ceramic tiles, and producing the UHPC exterior shell of the cross.

The structure consists of a central connection core with four cross arms, each weighing nearly 13 metric tons. The interior is accessible, and the complete structure has a total weight of approximately 110 metric tons. One of the greatest challenges was the extraordinary geometry featuring doubly curved surfaces. To accommodate this design, a highly complex timber formwork system was created using glued laminated timber, multilayer wood panels, and rigid foam boards. Approximately 12,000 handcrafted tiles in eight different shades of white were installed according to a predefined pattern and secured in place before casting. The tiles were manufactured by Ceramica Cumella of Barcelona.

The duplex stainless steel framework, consisting of custom-fabricated components, was produced by Josef Gartner GmbH, a company specializing in façade construction. The inner formwork was made of 12 mm (0.47 in) flexible plywood with 4 mm (0.16 in) architectural concrete panels attached to its surface. Due to the complex geometry, each individual section had to be custom-fitted between the steel members. The inner formwork was attached to the steel frame using wooden clamps, allowing the formwork panels to be screwed into position. At the highest point of each section, an opening with a pipe connection was incorporated for the later placement of a 5 cm (2 in) thick UHPC layer.

The highly precise installation of the doubly curved formwork presented another major challenge. Successful execution required exact alignment of the self-supporting steel structure and final tensioning with tolerances of less than one centimeter. At the same time, a column-free and accessible interior space had to be achieved, placing significant demands on both engineering and structural design. A custom formwork assembly was fabricated for every corner of the cross. After tile placement and installation of the steel structure, the UHPC was cast through the designated pipe openings. This process created the outer UHPC shell of the cross, while the duplex steel structure serves as the load-bearing central core. One notable aspect of the manufacturing process was that the tiles were embedded directly into the UHPC rather than being attached with tile adhesive, as is typically the case. Natural stone from Catalonia was used for the interior cladding of the cross.

Due to restricted accessibility, all concrete placement was carried out manually. Ultra-High Performance Concrete based on NANODUR® Compound 5941 is self-consolidating and therefore ideally suited for complex geometries. The UHPC was placed through the designated pipe openings using buckets. Several times each day, batches of 25 liters (6.6 gallons) were produced on site in a compulsory-action mixer to ensure a constant supply of fresh concrete. Daily production volumes ranged from 250 to 400 liters (66–106 gallons). In total, approximately 20 m³ (26 yd³) of concrete were used for the project.

Once the concrete had cured, the formwork was carefully removed. Special attention was required to prevent damage to the tile surfaces and to allow the rigid foam components to be reused. The tiled surfaces were then cleaned and re-grouted in two layers to achieve a uniform and harmonious appearance.

After fabrication was completed, the individual cross segments were transported from Herzebrock-Clarholz in North Rhine-Westphalia to Barcelona using specially permitted heavy-haul transport. Due to width restrictions on French roadways, modifications to the transport route were necessary. Portions of the journey were therefore routed through Antwerp and then continued by ferry to Spain.

Preassembly on the roof of the basilica in Barcelona was carried out by Josef Gartner GmbH at a height of approximately 54 m (177 ft). The individual components were assembled and subsequently installed at an elevation exceeding 170 m (558 ft).

With the completion of the cross, the Sagrada Família has now reached the final height envisioned by Antoni Gaudí: 172.5 m (566 ft). This height was deliberately chosen so that the structure would not surpass the nearby Montjuïc hill. Gaudí believed that no human-made structure should rise higher than God’s creation. The Nativity Façade and the basilica’s crypt, both designed by Gaudí, have been part of the UNESCO World Heritage Site “Works of Antoni Gaudí” since 2005.

The completion of the cross and the Jesus Christ Tower marks another significant milestone in the history of the Sagrada Família. Full completion of the entire basilica complex is currently scheduled for 2036. Even today, the basilica attracts approximately five million visitors from around the world each year and continues to inspire as a unique combination of architecture, engineering excellence, and craftsmanship.

Photos: Sudholt-Wasemann

For further information, please contact:
Isabel Derstroff
marketing@dyckerhoff.com