Representing the living standards of the 1950s, the Serpentine House (Finnish: Käärmetalo) is one of the best-known residential developments in post-war Helsinki – among other merits, it has been listed by DOCOMOMO as a significant example of modern architecture in Finland. The building complex is currently undergoing major renovations, and the first phase was finished this spring. We asked architect Mona Schalin to shed light on the challenges encountered during the project and the planning issues relating particularly to renovating and restoring representatives of modern architecture.

the renovation and conservation of modern architecture.

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Architect Yrjö Lindegren designed the Serpentine House complex on Mäkelänkatu as a rental block for the City of Helsinki. The free-form chain of buildings winding through a sloping park-like plot forms an impressive overall composition, including two four-storey residential buildings completed in 1951, as well as a service building with a daycare centre and swimming pool finished in 1952.

 

The latest improvements to the Serpentine House's apartments, basement facilities and technical building services had been made in the 1980s. Preparations for the thorough renovation had been in the works long before the project was finally launched in November 2016. Heka-Kansanasunnot Oy, the company in charge of managing and maintaining the City of Helsinki rental properties in the area, had surveyed the condition of the buildings at the turn of the decade, concluding that the plinth, exterior plastering, balconies, roof structures and windows, for example, were in need of major repairs.

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Technology and aesthetics

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The state of the buildings was even worse than expected, which was revealed during the project planning, along with some structural surprises. Based on additional investigations and condition inspections, there was talk of introducing mechanical ventilation and adding insulating plaster to the weak exterior wall with a Betocel lightweight concrete block structure; the authorities, on the other hand, mandated that the architectural values and preservation level were to be respected.

The City Planning Department commissioned a thorough building history survey, and a local detailed plan amendment concerning the block was instituted. The exceptionally detailed protection regulations applied not only to the area of the plot and the buildings, but also to construction elements, the interiors and the fixtures and fittings in the apartments. According to the new detailed plan’s regulations, previously demolished or altered elements of the buildings had to be restored to adhere to the original execution of the design.

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As the implementation planning began, a method of renovation that respects the architectural characteristics of the building complex clearly emerged as an objective shared by the client, the authorities and the planning team. Interpreting the protection regulations was a topic of several discussions and negotiations with the building control and city planning authorities as well as the City Museum.

 

The renovation was a vast project. The technical building services were refurbished, and roof slab and wall structures, for instance, had to be rebuilt. The exterior plastering, eaves and all balconies were redone. Reparable windows and balcony doors were improved in terms of their thermal engineering, and any details that were in poor condition were replaced with corresponding new ones.

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All interior surfaces in the apartments were refinished, but special attention was given to the bathrooms, fixtures and fittings, and the kitchen cabinets. The idea of adding mechanical ventilation had already been abandoned at this point, and the natural ventilation was improved by installing replacement air vents in the apartments. As regards the common spaces, the staircases were painted and the laundry rooms and saunas renovated. The Building Control Department and City Museum monitored the fulfilment of the protection objectives at the job site by conducting sample inspections. There have been few cases in which the cooperation has run as smoothly as it did in this project with the project management, the general contractor and the skilled and ambitious site team.

 

Managing the details

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From the point of view of architectural planning, preparing the contract documents in the required detail is a challenge in a project like the Serpentine House, as all the construction elements that are to be replaced and repaired have to be listed and documented. Due to the exceptional geometry of the building complex, the balconies and eaves flashings, for example, had far more details and individual joint solutions than modern renovation projects usually do.

Installing updated building engineering into small 1950s apartments without resorting to copious chasings in the thin dividing walls required close collaboration within the project team. The electrical engineer worked with us to design a new, opening skirting board specifically for the Serpentine House to be used in parallel with the preserved original skirting. 

 

The phase of the renovation that was completed this spring, comprising 45 apartments, has served as a test lab of sorts before the overhaul of the next building of 144 units. The practices tried and adopted during the first phase include the completion of sample jobs in various areas of the site at an early enough stage to have time to alter the plans, if necessary. This has also enabled us to estimate the costs more accurately. ark

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Mona Schalin