Karatzas set the façade consultant firmly inside the project team, alongside the architect, the structural engineer, the main contractor and the client. The core responsibility, as he put it, is to act as a bridge, between the design intent of the architect and the buildability of the façade, and, as in any team, whether in construction or in sport, it only works if the members actually collaborate.

That framing came with a candid aside about geography. Skyline Facades has delivered more than fifty projects and designed over thirty bespoke aluminium systems for clients, the Arches Tower in New York, Beam on Farmer in Arizona, the Icon Tower in Tel Aviv, the Maldron Hotel in Brighton among them, yet almost none of it at home. Karatzas gave two reasons. The practice was founded during the depths of the Greek economic crisis, when construction had all but stopped; and until recently there was simply no real demand for a façade engineer in Greece. That, he said, has begun to change sharply in the last two or three years, buildings are taller, more luxurious and more complicated, and the cost of getting the construction wrong has risen with them.

The argument for bringing the engineer in early, “design assist”, followed from there: the sooner the façade specialist is involved, the more the final result can be optimised rather than corrected. From there the talk turned to its titular subject, architectural glass, light, transparency and the experience of space, and the way the choice of glass drives a building’s energy performance as much as its look.

He anchored the collaboration argument in one project, which the team knew internally as Project Costa: Old Paradise Street in London, a change-of-use scheme that turned a former Costa Coffee processing factory into a modern seven-storey office building, with architecture by FCBStudios, offered as an example of what happens when all the parties pull in the same direction.