The building now known as Lethes Theatre, located in Faro, Algarve, originally began as a Jesuit college in the 17th century.  The main body of the theater, the former church where the stalls and stage are located, features a barrel vault made of lime-mortared ceramic brick masonry. 

Intervention goal

The rehabilitation work was prompted by the discovery of significant structural damage to the vault above the stage area, which had subsided by 90% of its structural thickness and exhibited large open cracks.

Steps and techniques used

Given this situation, as a preventive measure, the vault was shored up, the theater was closed, and a diagnostic process was initiated alongside the design of a structural rehabilitation project. 

In the vault area above the stage, the reinforcement consisted of an exposed metal structure to provide horizontal bracing for the longitudinal supporting walls, effectively halting the deformation process of the vault. 

Support for the deformed vault was provided by suspension. This involved the use of tie rods connected at the bottom to a grid of thin steel plates, and at the top to six metal beams installed on the terrace. 

In addition to the structural reinforcement and consolidation, the theater was modernized. A new, more versatile stage was installed, along with a new automated fly system. Electrical systems were updated, and fire safety and accessibility conditions were improved with the addition of new emergency exits. 

Results

Given the building’s significant historical and cultural value, the intervention respected the fundamental principle of reversibility, with minimal intrusions made by the rehabilitation works.