Two respected architectural firms joined forces, expanding their expertise and starting fresh with a new name.
The story of Davidsson Tarkela Siren Architects Ltd began in June 2025, when two long-established companies, Davidsson Tarkela Architects and Siren Architects, merged. The new office was concisely named DT+S. The oldest architectural office in Finland is transferring its more than 100 years of experience to the next generation, with architect Niklas Mahlberg continuing as Managing Director of the new merged office. The founders of Davidsson Tarkela Architects, Aki Davidsson and Jaana Tarkela, will continue as lead architects and senior advisors in DT+S projects. Jukka Siren, who has led Siren Architects for over 40 years, will become an senior advisor.
Significant portfolio of expertise
The integration enables DT+S to offer its clients versatile solutions for various sectors of architectural design and to respond even better to the demanding challenges of the building industry. The office has long and extensive experience in the design of demanding and culturally and historically significant renovation projects and new construction projects. Both firms have received numerous architectural awards for their designs.
“Today, architectural firms are expected to provide new and different design-related services, which we are now better able to meet thanks to the integration. As our services expand, we still want DT+S to remain a pure architecture firm,” says Jukka Siren, highlighting the new opportunities that the merger brings.
Impressive references
DT+S’s list of references includes many well-known projects in Finland and abroad, such as the Clarion Hotel Helsinki, the Graniittitalo and Ympyrätalo buildings, and the K4 block of the Torikortteli district containing the Helsinki City Museum, as well as the renovation of sites such as the Finnish National Theater, Lahti City Hall, the Kuopio Museum, and the long-distance transport terminals at the Kamppi Helsinki shopping centre. The office’s long list of references also includes the Parliament House designed by J.S. Sirén, the Linz Concert Hall, and the Baghdad Conference Palace in Iraq.
In addition to renovation projects, the design of new buildings is also an important part of DT+S’s business. The office’s projects include fire and rescue stations, educational institutions, nursing homes, sports and leisure buildings, hotels and congress centres, and offices. The latest design projects in Finland include the renovation and expansion of the Tapiola swimming hall, the Elmo and Nokia swimming halls, the renovation of the Kela headquarters, the Kontula rescue station, and the Nuijala carbon-neutral thermal power plant.
Timeless architecture and continuous development
DT+S will continue to focus on solution-oriented and customer-centric approaches.
“Expertise and customer relationships are at the heart of our operations. Our extensive knowledge is linked to people, memories, and inherited expertise. Experience develops a way of thinking that strengthens our ability to operate in an ever-changing society and operating environment. You have to understand the past and the present in order to develop the future,” says Aki Davidsson.
“Every project is new. Architectural solutions are created from individual projects. We do not replicate architecture or functional solutions. Our working method respects the project, and our goal is to give the project an individual form. For us, open-mindedness and researching the right things are important. Architecture has deep roots, which is why it must be able to last over time,” continues Jaana Tarkela.
“The integration process continues from here: next summer, we will move into the same premises, which will combine the best aspects of both offices – the people, expertise, and culture. Creating a new architectural office is a unique and demanding project, combining the creation of new perspectives and the ability to develop,” says Niklas Mahlberg.
DT+S in brief
Davidsson Tarkela Siren Architects (DT+S) specializes in demanding renovation and new construction
projects. The company employs approximately 30 architecture professionals in Helsinki. The company is
part of the Solwers Group.
dtsa.fi
@dts.architects
