The silhouette of Barcelona cannot be understood without the cranes and geometric shapes that, inch by inch, are raising Antoni Gaudí’s most famous temple. The city’s air, always laden with that mixture of saltpeter and asphalt, is now witnessing how the basilica is gradually revealing some of its best-kept secrets—those architectural details that are not visible at first glance but which underpin the modernist architect’s grand vision.
Behind the majesty of the Tower of Jesus—which the Sagrada Família ’s architectural team plans to complete before the end of 2025—lies a surprising technical innovation. Project leaders have revealed that the various components making up the temple’s six central towers have been joined using a version of the well-known Loctite adhesive, designed exclusively for this project. The unveiling of this method coincides with a double anniversary: the centennial of Antoni Gaudí’s death and the 150th anniversary of Henkel, the German multinational that manufactures the product.
24 metric tons of structural joints
The use of this adhesive is no minor detail in the temple’s design. In total, 24 metric tons of this product have been used to bond the stone and steel of the 826 prefabricated panels that form the six central towers, among which the Tower of Jesus—blessed by Pope Leo XIV—stands out.
According to the temple’s architects, this system has enabled spectacular progress on the project, increasing the speed of construction tenfold and resulting in an estimated savings of 40 years of labor. The main advantage of this component is its extremely high strength, as it fuses both materials into a single block and guarantees exceptional durability that, according to experts, does not degrade over time.
Liquid precision and 30 kilos per panel
The adhesive specifically developed for the monument is Loctite EA 9497, and nearly 30 kilograms of the product have been required for each of the basilica’s structural panels.
The application process requires millimeter-level precision. The adhesive is initially injected in liquid form to ensure it fully conforms to the textures of the surfaces and fills any cavities, guaranteeing perfect contact between the parts. Once in place, the pieces undergo a 24-hour period under strictly controlled thermal conditions. After this process, the adhesive becomes completely inert, transforming the assembly into a modular monolithic structure capable of withstanding the passage of centuries.
