RESTORATION AND ANALYSIS OF THE WOODEN CEILING OF ROOM “A” OR “GALARIETTA FATA A MOSAICHO” IN THE NYMPHAEUM OF PALAZZO ARESE BORROMEO, CESANO MADERNO (MB)

Room “A”, also known as the “Galarietta fata a mosaicho”, is one of the most significant spaces within the 17th-century “Appartamento alla Mosaicha”, commonly referred to as the Nymphaeum, in Palazzo Arese Borromeo. Its uniqueness lies in the rich decoration of the floor, walls, and vaults, all adorned with black and white river-pebble mosaics forming geometric and floral motifs.

Recently, the mosaic ceiling of this room showed signs of structural distress, particularly affecting the main wooden beams.

The firm Foppoli Moretta e Associati was therefore commissioned by the Municipality of Cesano Maderno to carry out an in-depth assessment of the wooden structure’s condition, aiming to identify the causes of the ongoing deterioration.

To obtain a highly accurate and reliable graphic base, a laser-scanner survey of the entire room was conducted—both from below (intrados) and above (extrados)—and integrated with a photogrammetric survey.

To enhance the understanding of the structure, a thorough inspection of the timber elements was carried out, focusing on their state of preservation and any structural issues. On the main beams—especially in areas of concern or where direct inspection was not feasible—a detailed instrumental analysis was performed using a specialized penetrometer known as a Resistograph. At each testing point, wood moisture content was also measured.

Additionally, three core samples were taken using a Pressler increment borer, followed by microscopic analysis to identify the wood species used.

The diagnostic campaign represents a fundamental step in assessing the conservation status of the ceiling, with the goal of planning a future structural reinforcement intervention that can both preserve and enhance the material and architectural qualities of this historically and culturally valuable site.