A century is just a mere moment for a valuable building in the heart of a city. That is why the new and highly modern office building located at Kasarmikatu 21 in Helsinki, Finland, is designed to withstand time.

Kasarmikatu 21 is a high-quality natural stone building inside and out.

Exceptional endeavour

It is not often a completely new building is built in the city centre of a metropolis, and this is also true for the Finnish capital, Helsinki. Sometimes decades go by without any new constructions. This is about to change with the unique project of raising a new office building on the north end of the Kasarmitori square, just a block away from the Esplanadi park in the centre of the city.

Kasarmitori square is surrounded by historically valuable buildings. Placing a modernly equipped edifice, which is serving today’s work environment and business needs, as a natural extension to that architectural cavalcade requires precision of both the design as well as the execution of the project.

While the new building was to meet the needs of its time, it was still important that it would fit into the surroundings. To complement the older stone buildings in the neighbourhood, a light-toned durable sandstone with a matte finish that would hold its dignified look for centuries was chosen for the facade.

Carefully selected materials

Kasarmikatu 21 is a high-quality natural stone building inside and out. When moving indoors, the light sandstone is accompanied by the stately and well-aging oak.

The stone material of the floors in the lobbies and other public areas is highly durable and creates a unified, elegant appearance throughout the building. A large atrium in the centre of the structure distributes natural light year round.

All construction and interior materials are hand-picked amongst the most prized and reliable tried-and-tested options available. While still less used in Finland, sandstone is a popular material in European high-quality construction and it blends beautifully with the grand glass surfaces of the facade.


Varying spaces

The spacious structure of the building enables that which often cannot be achieved in an office space located in the city centre: even a larger organisation is able to share a floor and work together in one unified space.

A boundless area encouraging to meet with others is easily modified into a space that ensures privacy and concentration. The modern, varying spaces have been designed to retain a stable and stylish layout regardless of how and for what the space is being utilised, without any technical constructions apparent to the users.

Sarlotta Narjus , the architect at SARC Architects in charge of the usability of the new office building knows that a space must adapt to its users. A space built in accordance with this principle is both flexible and practical.

Sustainable construction

The building at Kasarmikatu 21 takes its environment into account not only aesthetically but also in the choice of materials and the way it is constructed, and it applies directly for the highest, platinum-level LEED certificate (Leadership in Energy and Environmental Design).

As more and more people take a bike to work, the new building features a spacious bicycle garage with convenient locker room facilities.

From the start, the complex construction project has been met with the respect and concentration it requires. Both Antti-Matti Siikala , the architect-in-charge, as well as the developers knew early on that simply placing a white cube at the edge of Kasarmitori square would not cut it. From the resulting novel design process, still honouring traditions, arises an architecturally interesting, modern and sustainable building in natural stone, which respects its environment and the needs of its users.

More information on the LEED environmental certification from the Green Building Council Finland website.



There is more to this office building on Kasarmitori Square in downtown Helsinki than bricks and mortar.

Further details of the project



Kasarmitori Square has served as a versatile venue over the last century, accommodating everything from military parades to dance events for young people in the 1960s and 70s.

See the full history



The modern building has a unique location; it´s a very rare occasion to be able to build a new construction into Helsinki CBD.

Check out the architecture



The Kasarmikatu 21 development is a joint undertaking of the venture capital and real estate investment specialists Ahlström Capital, HGR Property Partners and YIT.

Some facts about the developer