Jack Wooler spoke to Antti Nousjoki of ALA architects about how Finland’s biggest library combines an inviting ‘bridge’ structure with shifting timber and glass facades
The new Oodi Library in Helsinki is a modern take on the building typology, offering residents and visitors a host of publicly accessible functions over its three floors. Named after the Finnish word for ‘ode,’ the 17,250 m2 building includes amenities such as a restaurant and cinema on its ground floor, 3D printing machines and games rooms on its second, and a traditional library reading space on its third, nicknamed ‘book heaven’ by the team behind the project. The building was in part commissioned to celebrate the centenary of Finnish independence in 2017. While the main structure was built in time for the celebrations, this completion target was deemed too optimistic, and the library was instead fully opened a year later on 5 December 2018, a day before the country’s 101st birthday. Now open to the public, the building displays a fluid geometry of curved, shifting lines. The design of the €98m project features an innovative steel bridge which houses its second floor, holds the third floor up, and allows the ground floor to be column-free. The library is owned, developed and operated by the city of Helsinki, and is part of the city’s almost 40-strong network of library facilities. Not intended to be the administrative core or focused on the traditional storage of books – with the city’s collection already existing in other buildings and available through online booking – the vision was to create a publicly open and contemporary centrepiece for the area, concentrating more on the amenities offered. To fulfil this vision, ALA Architects were hired through a rigorous 548-entrant open design competition, which was anonymous up until the end of the project’s second phase. The architect’s design now having been realised, the building responds to local calls for a new public space, providing visitors, residents and commuters alike a place to meet and relax.
One remaining site
The site that was chosen is in the centre of Helsinki, just across the road from the stone-clad columns of The Parliament House, and surrounded by multiple large scale cultural attractions such as the Helsinki Music Centre and the Museum of Contemporary Art. Sitting in the most densely urbanised area of the city, the library is surrounded by office space to the north, the main railway and metro stations to the south, the city park to the east, and urban areas to the west, including the aforementioned cultural and political buildings. Formerly a rail depot, the transport functions on the site were moved further away from the centre, and it was left as empty brownfield land. Inaccessible and undeveloped, according to the project architects it was the last site left available in the ‘heart’ of downtown Helsinki. The area around the site is fairly densely planned, and mostly comprises 6-8 storey office and commercial developments, which residents have reportedly begun to tire of. “Being the final block of the masterplan for the area, there was public pressure to not turn this into another headquarters, but instead to create a public space for the citizens,” says Antti Nousjoki, principal at ALA. “Alongside this new public building, a large square was planned facing the Houses of Parliament, creating a centre for public and civic institutions, so this was the final piece of that puzzle.”
A fluid exterior
When facing the library’s large glass entrance, timber cladding appears to grow out of the ground from either side of the glazing, stretching over the second floor and above visitors’ heads to a cantilevered balcony. Above this warping timber-clad wall sits the porous box of the third floor. Antti explores why this fluid shape was chosen: “We had to follow the existing masterplan, which dictated how the volume sits in relation to the other buildings in the area. We tried to leave the geometry of the surrounding cityscape somewhat behind us, however.” He continues: “What we needed to do then was to break out of that box as much as we legally could, so the building twists out of the given box shape and cantilevers out of the given footprint, without touching the ground outside the masterplan limit.” Taking a step back from this glazed entranceway and out from underneath the shade of the balcony, visitors can take a look at the whole building from its western side. From this angle, each of the library’s three levels are visually defined thanks to the varying material palette – the open glass elements of the bottom floor, the timber-clad middle floor, and the expansive glazing of the rectilinear box on the third floor, the proportions of all of which shift with the building’s flowing shape. The middle volume was one of the more complex elements, not just because of the significant process of getting the fire and weatherproofing of the light finished birch wood cladding approved, but also due to the interesting structural properties of the steel framing underneath. Antti explains: “The second floor acts as a kind of double arched bridge, with the third floor built up on top of this. Because of this, the ground floor has very little vertical structure, and is column free, both inside and out.” Looking above the bridge and the glazed structure atop it, the roof is supported by steel columns and beams, and within the beams are timber infill elements. Utilising steel across the roof, the accumulation of its intended patina is already visible, the ‘wear and tear’ upon which “makes it look even more beautiful,” says the architect.
Thanks to the envelope’s large areas of transparency, the interiors allow a significant amount of daylight. On the entranceway, this is mitigated somewhat by shading from the large balcony canopy. The building’s copious glazing is formed of multiple large insulated panels of differing sizes, with the often harsh Finnish climate necessitating high U-values. The lateral wind loads and parts of the horizontal wind loads are taken by these glass columns, and were part of the fulfilment to the building’s intended 150 year lifespan. The building has been engineered to endure the maximum potential number of snowstorms likely during that period, with the weather expected to get more extreme each year. “The glass wall detailing is “quite interesting,” explains the architect, “because the walls are not of equal height – it is out of proportion a little bit, something you might see in typhoon zones,” which in part explains why the panels needed to be shaped around a shifting geometry. As the building is airtight, there was no need for point fixing of these glass panels. Instead the fixing has been integrated in the flooring’s detail, and glued in. In order to restrain the high level of solar gain on the top floor, the architects used software to generate a gradient pattern from totally transparent to an almost solid colour at different points across the facade, which was then printed onto the glass panels. “That print has a big effect on how white the building is from the outside – not black like typical glass buildings,” says Nousjoki. He adds: “Because of this light control, the curtains are rarely used.” Above the third floor, the surrounding daylighting is also complemented bycircular skylights which ‘puncture’ through the roofs at carefully chosen intervals. Unlike on the other two floors, here the building’s timber volume incorporates a small band of gaps between the cladding, providing more restricted daylight to the second floor.
On the street level, the ground floor has been designed as an extension of the nearby open space, with the intention of it becoming an integral part of the city’s public sphere. As there is a lot of visual as well as audible noise around this area, the more group-oriented functions are located on this floor, including the restaurant, along with an acoustically insulated space for the National Audiovisual Institute’s cinema. Both of these can be seen from the street level exterior. Heading inside from the main entrance, visitors first encounter the checkout and returns functions, with a restaurant and the main staircase to their left, and to the right an information desk to guide them around the three levels. Next to the information desk are the escalators and drop-in computers, and there are also lifts on both sides of the ground floor. On this floor, the interior palette is based on whites, greys and black, and the ceiling is a continued part of the building’s timber bridge arched over it, and as such is clad in finished spruce. Going up what the architect describes as a “dramatic double staircase, almost like a drill bit going through the solid middle floor,” visitors are led to the middle layer, a more closed, modular volume of individual rooms and specific functions that require certain conditions such as acoustic isolation, or in the case of the urban workshop spaces provided, specific air control and ventilation systems. “Such functions of a contemporary public library don’t do well in open spaces, and are not that comfortable in a changing daylight condition,” says Antti. “As such, the middle floor is a collection of the programme that would have been compromised on the other levels.” These functions include reservable group rooms, recording studios, games rooms, 3D printers, learning spaces and workstations, all intended to provide valuable but free amenities to the public. With this closed volume necessitating daylighting be kept to a minimum, LEDs have instead been used to offer controlled lighting, as the ever-changing sunlight can be troublesome when working with screens, and some working environments require differing levels of light that cannot be guaranteed from daylighting alone. Finally, back to the spiral staircase and up to the top floor – which like the first is more open – is where ‘book heaven’ is found, delivering a more traditional library function. While it is connected visually to the city centre through the extensive glazing, the glass simultaneously separates the floor from the noise of street level thanks to its high insulation performance. Here are the usual racks of books, along with an event space and ‘story room.’ Surrounding this area is the continued theme of timber, covering all the flooring, including embedded and raised sections, as well as trilateral panels connecting them wherever timber stairs are not, creating a shifting space that mimics the building’s exterior. Using the same spruce material as on the floor below was not suitable here however, because it’s a relatively soft wood. Instead, the architects specified an imported oak to offer durability against the effects of numerous daily visitors. The ceiling here helps to aid the expansive glazing surrounding it to emphasise the sense of bringing the outdoors in, with a fluid curvature that ebbs and flows as the roof does. Antti provides further detail: “There’s constantly a slight mood change of going from a taller to a lower space. The acoustics imperceptibly change every metre because of this movement, and visually you can’t see the whole ceiling anywhere from within the floor, so as your vantage point shifts the geometry of the ceiling changes when new curves are exposed.”
Challenges & reactions
Overall, the reception has reportedly been “overwhelmingly positive,” with the building reaching the 1 million visitormark in just over three months – particularly impressive in a city of around 600,000 people. Antti reflects on some of the key challenges that led to this success: “For us, the most challenging part was to win the competition, especially the second phase. Otherwise, the wood cladding of the twisting cantilevered west facade was probably the main challenge, production-wise. “Our office has good experience of taking a 3D model and turning it into production drawings however, and so we were able to produce the final documents that went directly into the CNC machines, straight from our office into the logger.” He muses further on architects’ changing role: “There has been a lot of talk in our industry about how architects have become distanced from the construction process, but I would strongly argue against that. At least from our office’s point of view, it’s an almost historical level of involvement when you consider that we designed the building and its shape, and were then able to turn that shape into a set of production data that went directly into the milling machines.” Though the project was stuck slightly behind schedule, making the last six months of work “pretty frantic,” the building had to be, and was, completed and opened during the centenary year, which Antti in part dedicates to this level of involvement. He concluded: “That was both fun and exciting, and also made me proud of our young data team, who are really displaying how architects can be more involved in the contemporary world of digitalised construction.”