The Helsinki telephone company HPY began its operations in rented premises in 1882, but within a few years, its telephone exchange was running short on space. Lars Sonck, one of the foremost names in natural stone architecture, was tasked with the design of the new office building. The stone palace on Korkeavuorenkatu is representative of granite buildings in the National Romantic style, which reached the peak of its popularity around the turn of the 20th century.
The telephone company had only recently moved to rented premises in the Grönqvist building on Pohjois-Esplanadi when it was deemed immediately necessary to acquire more room and to purchase a building for the company, as by 1901 it already had 4,200 customers and its current premises could not hope to cater to more than 5,500 subscribers.
The company's board of directors purchased a plot on Korkeavuorenkatu, demolishing an older property before constructing the new office building. Architect Lars Sonck was invited to design the head offices, equipment rooms and housing units. As there was no frame of reference for the building in Finland, he was tasked with familiarising himself with the structures, interiors and equipment of continental telephone exchanges.
Sonck began the project in 1901, at the same time as Tampere Cathedral, considered by many to be his most important work, was under construction. Despite his busy schedule, Sonck was able to simultaneously submit a proposal to the National Museum's design contest and draw Sibelius's home Ainola on the shores of lake Tuusula. He was also working on designs for the Eira hospital, among other projects. The buildings he designed varied in their functions, but their architectural solutions were similar.
As planning premises suitable for technical equipment was a novel concept, the arrangement of the facilities had to be altered several times during the design process. The telephone company's board of directors approved the final plans in early 1904. The prestigious building was completed three years later.
Granite and soapstone
The walls of the National Romantic stone palace are built of brick, and their exterior covered with carefully selected, cut granite stones of many different shades, as well as smoothed soapstone of a light colour. The large stones are attached to the load-bearing brick wall with cross-stones, mortar and metal supports.
The noteworthy features of the building include its magnificent staircase and the facade's granite coating of stones of various colours. The main entrance is framed by a triangle reminiscent of Sonck's design for Tampere Cathedral.
An ornamental ribbon across the bay window of the tower acts as a reminder of the building's original purpose. The central exchange was located in the attic, just below the steep roof. Other floors housed offices and employees' apartments.
As the amount of households with telephones increased rapidly, Sonck designed an extension to the building in 1912. The windows of the stone palace's facade were expanded in 1914 and 1929, again with Lars Sonck as the architect. The iron bars in front of the basement windows are also from his pen.
Originally of red brick, the roof of the building was replaced with copper in 1960. The change was designed by architect Kurt Simberg.
Renovation stone by stone
The exterior and interior of the stone palace were renovated and converted into modern office facilities in 2012. The building’s facade and part of the interior, including the magnificent staircase, are listed. Consequently, the renovation project was carried out in close co-operation with Helsinki City Museum.
Time had taken its toll on the hundred-year-old facade, which was sorely in need of renovation. The building's tower, in particular, had been at the mercy of the elements. The lower part of the building has been better preserved, since the protruding roof covers the facade.
Care was taken during the renovation to preserve as many of the old details as possible, while ensuring the property's functionality as a modern office space.
In the case of the tower's facade, each stone was removed by hand and individually numbered. The work has been enormous in scope, as the largest rocks can weigh hundreds of kilogrammes. New structures for drainage and ventilation were installed in the exterior wall. After this, the stones were placed back in their numbered order.
On the lower floors of the building, the facade stones could be left in place, and the seams between them replastered.
Interior renovations, including those of the murals, were carried out by conservators from the City Museum. The building's interior was otherwise still in good condition, having previously been renovated in 2006. That time, the property was fitted with modern building service systems.
- Address: Korkeavuorenkatu 35
- Year of construction: 1907
- Architect: Lars Sonck
- Style: Art Nouveau stone palace
- City block: Sampi