A new roof covering for the Sala Carpanini of the Palazzo Civico in Turin

The old covering of the Sala Carpanini of the Palazzo Civico in Turin, an iron-glass structure from the early 1900s, has been replaced with a new one constructed with the EKU 50 GLASS system for mullion and transom curtain walls.

The roof covering of the Sala Carpanini of the Turin Civic Palace is an iron-glass structure from the early 1900s, typical of many public buildings in various cities. “There are many examples of this in Turin, Milan, Florence and Rome,” explains engineer Marco Tobaldini.

“Large buildings in the historic centres often had internal courtyards that were often covered by steel and glass roofing, becoming the headquarters of post offices, banks, etc. This area, this sala in Turin, has been dedicated to a politician and deputy mayor of the city”.

The main skylight has a size of circa 10×18 metres with other small skylights along the perimeter, the total glassed area being about 200 square metres. This skylight is formed by a reticular-beam structure covered by wired glass. “The constructive solutions adopted are typical of the early twentieth century” continues engineer Tobaldini.

“Wired glass was the safety glass of that time, in the glass paste a metal net was inserted which prevented the glass, if it broke, because of a hailstorm for example, not to slip off the supports and not to fall”.

Before the intervention

How was the intervention carried out?

First of all, all the necessary static and seismic testing of the existing structure was made to identify any critical elements. The structure was quite well constructed for loads such as wind, snow, etc., however there was a problem with the undersizing of the purlins.

The purlins are the secondary structures that support the glass, and they had to be replaced. They were made of 45x80mm “C” iron bars, which were replaced with heavier HEA 100 beams able to exploit the greater bearing capacity of the new aluminium frame that holds the glass. There was no need to do any work on the main structures.

Inside the trusses, a square-grid, glass curtain ceiling was mounted, a ceiling similar to those used in contemporary architecture. Being made of opaque glass it prevented the view of the metal structures above, but allowed the passage of light. This ceiling was easily disassembled and reinstalled at the end of the intervention.

EKU 50 GLASS system for the new roof covering

For the new roof covering, the EKU 50 GLASS facade and transom system was used, a system designed by the Profilati Group to simplify the creation of the various types of facades as much as possible, also thanks to a series of dedicated accessories. Not only vertical facades, therefore, but also inclined facades, domes, pyramids, tunnels and polygonal constructions, structures that are always characterized by luminosity, elegance and minimal visual profiles.

Given that the shape of the structure was not a perfect rectangle, there were difficulties in squaring during installation. “The rectangle was a little oblique, there was an out-of-square of about 30 cm” emphasizes Carlo Marangione, owner of Blindoor Costruzioni.

As can be seen from the photo n.8, the uprights and crosspieces of the rear triangle of the structure do not coincide with those of the longer side. “To find the exact geometry of the glass panels, we had to make wooden templates, on the basis of which we installed the aluminium profiles” continues Carlo Marangione.

“In my opinion, if everything had been done only theoretically on the computer, we would have risked wasting material, so we relied on our practical work experience. Of course we agreed the intervention together with engineer Tobaldini, who was very pleased with the final result.”

The new roof covering is constructed in modern safety glass, HST treated laminated glass, heat-soaked, which substantially reduces the risk of breakage.

Project summary