Lm135,000 restoration job on Senglea's main gate

Senglea's main gate, one of Cottonera's historic monuments, has been restored to its original splendour in a Lm135,000 project entrusted to the restoration unit of the Works Division.

The work involved the thorough restoration of the fortifications which, like other parts of the Cottonera bastions, suffered extensive damage through weathering and years of neglect.

"The globigerina limestone paving of the platform terrace was extensively damaged and missing in some areas. This allowed rain water to seep into the structure, causing irreversible damage," restorers Stephen Spiteri and Paul Saliba from the Works Division said.

"The primary concern was to ensure a minimum loss of the original fabric. Where the stone was extensively deteriorated, stone blocks were replaced," they said.

In places where the stone was less damaged, the restorers used a system known as "poulticing" to reduce the salts present in the wall. Salts in stone, in fact, absorbed water from moist air on humid days and this sped up the weathering process.

"The remedy involved treating the surfaces with various applications of clay and paper pulp and de-ionised water." The function of the poultice was to draw salts out of the walls to reduce the concentration.

The restorers said friable stonework was consolidated without blocking the pores in the stone during the process. "Detached layers were then injected with a lime-based mortar manufactured specifically for such use. The stonework was cleaned from harmful substances using low pressure micro blasting and cycles of poulticing with a weak solution of ammonium bicarbonate. Yet, the patina acquired by stone was carefully retained," they said.

They said plants growing in stone crevices had caused deterioration. "The roots and stems moved the stones and allowed rain water to penetrate the structure and this created more damage to the rampart," they explained.

Architect Hermann Bonnici supervised the work.

Resources and Infrastructure Minister Ninu Zammit said when contacted that courses to train Works Division employees in "general restoration" and in the restoration of baroque architecture were being organised by the ministry, in collaboration with the Building Industry Consultative Council and the Department of Baroque Studies at the University of Malta.

He said the Works Division was restoring a number of buildings including mediaeval chapels, baroque portals and palaces and it was vital for restorers to be "knowledgeable and specialised".

"Restorers must know which methods had been used in buildings of different eras for instance," the minister said.

Mr Zammit said workers second-hand the latest restoration methods, following methods used abroad to treat stone in the best possible manner.