The Martta café

In May 2023, the Marttakahvila café in Joensuu relocated across the market square to the side opposite its previous location, which presented a convenient opportunity to upgrade the café to a more modern look.

Lue artikkeli suomeksi täältä.

The Marttakahvio now lies on a line formed by the town hall and the art museum and is easily accessible from several directions. Its two building masses are connected to each other by a covered area for enjoying coffee and meeting up with friends.

Both buildings are constructed from CLT elements. The roof shape is a so-called slanted gable roof where opposite corners are at the same height. The same design language continues in the pergola canopy. Glulam serves as the load-bearing material for both the roof and canopies, and a clear plexiglass covering protects the canopy from the weather.

As the buildings are designed for summer use only, there is no heating or ventilation equipment, but the location on the market allows for a connection to municipal utilities.

The Martha Association chose wood as the building material because of its environmental friendliness across its lifecycle. Other sustainable choices in line with the association’s general environmental policies include the charred exterior cladding that is made from recycled boards.

Technical solutions

The load-bearing structure is a CLT frame used for the outer walls, partition walls, and intermediate floor. The pergola/terrace has a glulam pillar-beam structure, while a lattice structure is used for the roof.

The fire class is P3, which allows the use of wooden surfaces as visual elements without fire protection. Two sides of each building have a visible CLT façade, whereas the other two sides are clad with charred recycled wood.

The entire structure follows the “Design for deconstruction” (DfD) principle, which considers the eventual reuse of building parts and the building itself at the end of the building’s lifecycle. This option for reuse placed its own demands on the technical solutions. Once assembled, the building masses needed to be transported as volumetric elements to the market square – and back again at the end of the rental period. This also meant that the pergola/terrace roof structure would need to be installed and eventually dismantled.

The construction project

Planning began in August 2022, and the building permit was granted in January 2023.

Two educational institutions collaborated on the actual construction of Marttakahvio. Building construction students from the Riveria Vocational School assembled the CLT elements and the actual buildings in Kontiolahti in February 2023, and logistics students moved the buildings in April to the Joensuu market where the installation work continued. Building technology students from the same school did the HVAC work.

Students from the Karelia University of Applied Sciences were in charge of the remaining project management together with the construction project’s other stakeholders. Three civil engineering students (Nina Hiltunen, Kirill Pippola, and Juho Alder) handled the procurement planning, procurement, site planning, scheduling, and safety plans as part of their bachelor’s thesis, under the guidance of Karelia UAS construction engineering teachers Annikki Tanskanen and Timo Pakarinen.

A project on such prime real-estate was particularly intriguing for the students. They seldom have such an incredible opportunity to gain work experience while also writing theses and passing skill evaluations for their studies. The project’s high visibility and expanded opportunities inspired students to put their best foot forward. CLT construction was a novelty for everyone involved, and all parties were eager to gain hands-on experience with this type of prefabricated element. The construction site’s central location at the Joensuu market brought its own challenges as the work could of course not jeopardise the operation and safety of the market.

As a customer, Pohjois-Karjalan Marttapalvelut Oy wanted to encourage local multidisciplinary cooperation between educational institutions and companies. The goal of the construction project was to provide students from both educational institutions with a unique opportunity to learn the ins and outs of a multi-party construction project in such a challenging environment. From the perspective of the educational institutions, the project was a huge success: this type of project work is the best possible learning environment and provides students with valuable lessons in collaborating with other parties on a construction project.

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