FOUNDATION UNDERPINNING AND STRUCTURAL CONSOLIDATION IN HERITAGE RESTORATION

The Restoration of the Casa del Labrador at the Royal Palace of Aranjuez:

Heritage restoration requires multidisciplinary teams and specialized companies with experience in interventions on unique structures. The rehabilitation of the Casa del Labrador is a clear example of a complex and necessary undertaking, addressing structural issues caused by inadequate load transmission to the ground.

The process involved preliminary studies, structural monitoring, and the intervention of specialized technicians, restorers, and master craftsmen in traditional trades. Work included foundation underpinning using micropiles, structural reinforcement and consolidation, protection and restoration of furniture, interior ornamentation, and façades, as well as roofing and installation upgrades. KALAM’s expertise in similar interventions was crucial in ensuring the project’s success, allowing the building’s reopening within the Cultural Landscape of Aranjuez, a UNESCO World Heritage Site.

This entry summarizes the intervention and includes a video prepared at the end of the works detailing the restoration process.

The Casa del Labrador: Historical Significance 

In the late 18th century, King Charles IV commissioned the construction of a palace at the eastern end of the gardens of Aranjuez, influenced by French maisons and Italian casinos. Designed by Juan de Villanueva, the building is located near the Tagus River and is distinguished by its rich interior ornamentation and valuable historic-artistic assets, including silks, mural paintings, furniture, and sculptures.

Addressing Structural Issues Due to Inadequate Foundations

Preliminary Studies, Diagnosis, and Monitoring 

In 2017, the appearance of cracks in façades, floors, and ceilings prompted an initial phase of monitoring and analysis conducted by Patrimonio Nacional, the property owner. Various studies confirmed that the structural issues stemmed from inadequate foundations and the proximity of the water table.

The underpinning carried out in the early 20th century had not reached a sufficiently stable substrate, making a new foundation necessary. As the project design was nearing completion, Storm Filomena exacerbated the monitored cracks, prompting an emergency intervention in March 2021.

Protection, Removal of Furnishings, and Preventive Measures 

Given the complexity of the intervention, all furniture was removed and cataloged, and protective measures were implemented for ornaments, walls, ceilings, and structures to prevent damage and dust accumulation during the underpinning phase. Structural stabilization work included reinforcing painted ceilings and stitching structural cracks using special meshes and lime mortar to ensure stability before foundation work commenced.

Sensors were installed to monitor structural movements and ensure they remained within safety thresholds. Among the preliminary measures, the protection of Mariano Salvador Maella’s fresco painting stood out, involving a metal substructure and flexible protective elements. Additionally, the structural support for the encamonada vault sustaining the painting was reinforced. The original structure consisted of tensioned metal trusses that were not performing adequately, so three laminated timber trusses were installed to eliminate stress before further intervention.

Foundation Underpinning: Micropile Installation and Tie Beams 

The new foundation system consists of two types of micropiles distributed throughout the building’s footprint. A total of 500 micropiles with a diameter of 15 cm were installed to a depth of 15 meters around the perimeter and interior walls. In strategic locations, larger-diameter (30 cm) micropiles were placed at greater depths and inclined to prevent horizontal displacement.

The micropile heads were connected using tie beams and threaded steel dowels, allowing the load transfer from the walls to the foundation. The entire process was monitored in real time to control vibrations and ensure movements remained within established limits.

Structural Reinforcement and Architectural Restoration

Reinforcement of the Floor Structure in the Sala de la Compañía 

To reinforce the floor of the Sala de la Compañía, over 4,000 porcelain pieces from the Royal Factory of Buen Retiro were identified, dismantled, cleaned, and stored. The metal profiles were then cleaned and restored, and a new system of secondary beams, connectors, and a compression layer was installed. After completing the reinforcement, all pieces were repositioned to restore the original flooring.

Roof and Terrace Restoration 

The roof was renovated with slate cladding, incorporating thermal insulation to mitigate the extreme temperature fluctuations affecting the building. Finishing elements and mansards were restored by specialists in zinc and lead. Additionally, 2.5 mm thick lead sheeting was installed on flat terraces, ensuring waterproofing through properly executed joints, channels, and connections.

Façade Restoration and Recovery of Its Original Appearance 

The brick façades exhibited significant deterioration and aesthetic alterations dating back to the mid-20th century. Based on historical research, the decision was made to restore the original 19th-century appearance using a traditional lime render with colors and volumetric elements observed in Fernando Brambilla’s paintings.

Comprehensive Restoration for the Conservation of a Unique Asset

The restoration of the Casa del Labrador has preserved a site of invaluable historical and cultural significance. The complexity of the intervention demanded technical rigor, extensive experience, and meticulous control, given the invasive nature of certain works and potential risks associated with water infiltration and soil displacement.

KALAM’s extensive experience in protected heritage interventions, combined with its multidisciplinary team of technicians, restorers, and traditional craftsmen, was essential to the project’s success. The coordination between the project management, execution teams, and Patrimonio Nacional, as the project promoter, along with KALAM’s specialized intervention team, ensured the building’s preservation, allowing it to remain part of the World Heritage Site for many years to come.