As Oy Haagan Artturi

Haagan Artturi is an energy-efficient small apartment building in Helsinki’s Haaga district. It is based on a concept developed by Woodberg Oy in 2016 and designed to fit into the often peculiar shapes and sizes of infill construction plots.

Read the article in Finnish here.

The concept finally saw daylight here on Artturi Kanniston tie street, where it was developed further to use volumetric elements. This made construction quick and minimised the disturbance caused by the construction site. Sitting snugly on a piece of land that was carved out of the neighbouring plot, the shapes and proportions of Haagan Artturi and its façades subtly complement the surrounding milieu of gabled stone houses from the 1950s and 1960s. At the same time, the wooden façade stands out from its neighbours. While the choice of material is in line with the building’s solid wood frame, it also pays homage to the historic villas of the Haaga district, including the still-standing Villa Furuhäll, which is perched on a cliff on the other side of Tunnelitie street.

The street-side façade is decorated with regularly spaced window openings. In the courtyard, horizontal ribbons formed by contrasting colours tie the balconies and windows together, highlighting the way the apartments open on views of the surrounding bedrock and its long-standing pine trees. The façade cladding consists of 28 vertical panels punctuated by windowsills of white sheet metal.

Indoors, the wooden surfaces provide a warm, cosy atmosphere. Most of the apartments open in three directions and have large balconies facing the courtyard. Apartment sizes range from two to three bedrooms. The bedrooms are intentionally neutral in size, giving residents the freedom to decide their use and furnishings. The large windows let in plenty of natural light, and all the apartments have luscious views of the park.

Thanks to smart choices made during structural design, the apartments have atypically large amounts of visible wood surfaces on load-bearing structures and partition walls. For example, the cabinet in each apartment’s entryway is built from CLT boards. The façades are painted, and the spaces between the balconies are fire-treated in the same shade. Interior wood surfaces have a wax finish.

Indeed, wood’s role is exceptionally important in Haagan Artturi’s architecture, both indoors and outside.

Technical solutions

The building is built from prefabricated, solid wood volumetric elements. The load-bearing pillars are glulam, and CLT is used in the load-bearing and bracing walls. Structural stiffening is done with the CLT walls of the volumetric elements and with large CLT elements. Partition walls that are not load-bearing are either CLT walls or traditional pole-framed panel walls. As for the horizontal structures, the intermediate floors are made of LVL beams, excluding the CLT slabs of the stairwell. The roof structure is a nail plate lattice built on top of the volumetric elements of the topmost floor. It has factory-made roof trusses and a machine-seamed steel sheet roof. The roof’s thermal insulation is glass wool.

The building is in fire class P2. Thanks to the automatic extinguishing equipment and unusually thick exterior walls, it has been possible to leave plenty of wood visible inside the apartments.

The building uses geothermal heating and falls into energy class A (74 kWhE/m2). To produce the building’s general maintenance electricity, the roof is covered with 10 kWp solar panels. The automated ventilation is apartment-specific, and the apartments have water circulation floor heating. The team optimised the HVAC system’s efficiency and specific fan power and conducted a detailed EED simulation to measure the yield and efficiency of the geothermal heating. This approach ensured that the values used in calculations were realistic.

The construction project

  • Conceptualisation of the building type for infill construction 2016.
  • Development of a reference plan for municipal zoning begins in 2019.
  • Municipal zoning change enters into force on August 18th, 2020.
  • Construction design begins in 2020.
  • Building permit received October 4th, 2022.
  • Construction site established in early November 2022
  • Installation of volumetric elements begins in February 2023.
  • Construction complete in June 2023.


Antti Lehto on arkkitehti ja asuntosuunnittelun apulaisprofessori Aalto-yliopistossa arkkitehtuurin laitoksella sekä INARO:n ja Woodbergin osakas. Aleksi Niemeläinen on arkkitehti ja Futudesign Oy:n sekä Woodbergin osakas. Hanna Mattila ja Emilia Ellilä toimivat INARO:lla projektiarkkitehteinä useissa vaativissa asuntosuunnitteluhankkeissa.

INARO Oy on lukuisissa kilpailuissa palkittu helsinkiläinen arkkitehtitoimisto, jonka nimi on lyhenne sanoista Integrated Architecture Office, viitaten kestävään ympäristöön tähtäävään kokonaisvaltaiseen suunnitteluun.

Futudesign Oy on 2012 perustettu arkkitehtitoimisto, jonka monipuolinen arkkitehdeista, sisustusarkkitehdeista ja muotoilijoista koostuva tiimi on erikoistunut haastavien arkkitehtuurikohteiden korjaus- ja täydennysrakentamiseen sekä korkean profiilin sisustusarkkitehtuuriprojekteihin.


Project in brief

As. Oy Haagan Artturi

  • Location | Helsinki
  • Purpose | Residential building
  • Constructor/Client | Woodberg Oy & Puurakentajat Group Oy
  • Valmistumisvuosi | 2023
  • Floor area | 830 m2
  • Total area | 960 m2
  • Volume | 3 038 m3
  • Architectural Design | INARO Oy
  • Structural design | Sweco Rakennetekniikka Oy
  • Akustiikkasuunnittelu | A-Insinöörit suunnittelu Oy
  • Palotekninen suunnittelu | KK-Palokonsultti Oy
  • LVIA-suunnittelu | Sweco Talotekniikka Oy
  • Electrical design | Jeti-Sähkö Oy
  • Interior design | Futudesign Oy
  • Pääurakoitsija | Puurakentajat Rakennus Oy
  • Photographs | Mika Huisman
  • Text | Antti Lehto, Inaro