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Refurbishing a house like this is a dream come true, enthuses architect Stefan Gysel as we walk up the spiral staircase. Gysel is part of the long-established Bernese studio community Werkgruppe agw, a cooperative association of building professionals. His enthusiasm for the residential and commercial building at Spitalackerstrasse 60 in Bern is easy to follow: The filigree stone steps are impressive and the murals that adorn the way up are decorative. The zenithal light falls atmospherically from far above through the stairwell and down into the entrance hall. Climbing the stairs is like walking through a piece of urban and architectural history. Gysel knows the building like the back of his hand. Over the planning and construction period of the past few months, he has gotten to know it inside out, he says. He understood how it had been designed and constructed. He soon knew where the only possible location for a lift would be. But he also suspected that the installation would not be easy.

The scent of the Belle Époque
The corner building at Spitalackerstrasse 60 was built in 1906 by architect and master builder Antonio Perello. He also designed the five adjoining buildings to the west - a stately row of buildings in exposed brick and sandstone. These houses - like the entire Breitenrain/Spitalacker district - were built around the turn of the century, when Bern's election as the federal capital, the construction of the railroad and industrialization led to rapid population growth. The construction of the Kornhausbrücke bridge in 1898 was the starting signal for the development of the northern quarters, which until then had been separated from the old town by the deep incision of the Aare. Antonio Perello's corner house is a typical example of the ambitiously designed buildings of this boom period. The prestigious location on the corner of Spitalackerstrasse and Moserstrasse led to a special feature: a suspended, tower-shaped bay window with verandas adorns the diagonally cut corner façade. Richly decorated, cast-iron railings and supports exude the sophisticated scent of the Belle Époque.

No wonder, then, that the heritage conservation department was heavily involved in the conversion and renovation of the building from the very beginning. For decades, nothing had been touched, but nothing had been invested either, and the building was in serious need of renovation. Today, it is hard to imagine what it used to look like, says Stefan Gysel. The preservation authorities had a great interest in the renovation - and in ensuring that the building would be used carefully and respectfully in the future. After all, the easiest way to protect a building is to use it, according to the wisdom of conservationists. If a building stands empty, damage and decay can progress alarmingly quickly. Future-oriented maintenance therefore means not just preserving a protected building, but refreshing and upgrading it. The building should meet the diverse requirements and demands of the present day and be equipped for the future.

In an upscale residential building in a popular inner-city district, accessibility should be as barrier-free as possible. When - as at Spitalackerstrasse 60 - floor heights of more than three meters, a steep staircase and the client's desire for apartments for families with baby carriages or for older people are added to this, the installation of a lift is more than obvious. With minimal intervention, it is possible to almost completely preserve the historic building fabric and at the same time make it fit for a further cycle of use. The renovation on Spitalackerstrasse shows how the integration of a tailor-made lift system can ensure the preservation and continued use of the existing building fabric.

No zero-eight-fifteen lift
What Stefan Gysel had in mind was also the only solution in the eyes of the heritage conservation authorities: a small lift could be installed between the stairwell and the bathroom - where a reduit with hot water boiler was once installed - to provide direct access to all apartments. "I made a rough sketch and saw that this solution would work well with the existing apartment layouts. And it also makes sense for the store on the first floor and access to the basement," says Gysel. However, space was extremely tight, the historic building elements were sensitive and the existing structure was fraught with many unknowns. The architect suspected that it would not work with a zero-eight-fifteen elevator from a zero-eight-fifteen company. Specialists with a sense for individual, perhaps even unconventional solutions were needed. Specialists who shared Gysel's passion for the house and his commitment to respectful and careful renovation. He found them very close by, at the Bern-based lift manufacturer Emch.

Problems and solutions
The location of the lift was convincing in terms of organization and preservation, but it did pose a noise protection problem: the rear wall of the planned lift shaft was also the fire protection wall to the neighbouring building. Vibrations and structure-borne noise could not be ruled out with a conventional system. An initial solution envisaged two additional concrete walls, which would be decoupled in front of the fire protection wall and to which the elevator would be attached. This proposal raised various questions: How do you pour concrete walls into a narrow shaft that extends over several floors? Wouldn't the anchoring of the concrete walls also lead to structure-borne noise? And are two additional walls even possible if space is already tight? The optimal solution, it had to be admitted, had not yet been found.

After some deliberation, Emch had the brilliant idea: a steel frame as a self-supporting lift shaft, made up of 6 x 6 centimeter narrow tubes. A principle that is often used in glass lifts: there, too, the elevator usually hangs behind the glass shell on a steel frame. On Spitalackerstrasse, the steel scaffolding would be self-supporting in a shaft made of partially historic walls. Emch also found a convincing alternative for the anchoring and its sound transmission risk: instead of driving anchors into the fire protection wall, they worked with spacers: small threaded rods with plastic buffers that were clamped between the steel scaffolding and the shaft wall, thus stabilizing the elevator shaft.

The proposal not only solved the noise problem, but also saved valuable centimetres thanks to the slim design. Virtually invisible, hidden in the historic structure, the lift nevertheless has a wheelchair-accessible door width of 80 centimetres and an internal area of 1 by 1.15 meters. The practical implementation was a challenge, says Stefan Gysel. The house is old, the walls are of varying thickness and never completely straight. The architect and the Emch employees asked themselves: Would it work? Will the wall be far enough back or will there be a bottleneck? At the very beginning of the construction work, sounding holes were therefore cut into the ceilings through all floors. Only when the plumb bob could be lowered from the very top down to the basement did we know for sure: yes, it will work. Now the large holes for the elevator shaft could be cut. The thickest walls at the bottom determine the size of the shaft, while the clamped spacers at the top fill the air space.

Both sides share the same expertise
Working with the specialists from Emch is like working with highly specialized craftsmen or designers, says Gysel. They think and plan together, discuss, benefit from each other's expertise and find tailor-made solutions. He could go on and on: about the lift pit, which is actually too low, but which is now controlled by a protective room monitoring system. Or about the Hourdis ceilings, which had to be cut off for the lift shaft holes and which now rest on a newly built angle. All of this is technically feasible, but it takes a committed and competent partner like Emch to develop and implement such solutions. A partner who doesn't just sell a product, but designs a component. If I need more documentation, I can always get in touch, says Stefan Gysel as he leaves. He is well equipped with plans. "Such a beautiful house, I almost couldn't stop drawing!"