The architecture studio White Arkitekter has completed Sara Kulturhus Center, a wooden development with the world’s second tallest wooden tower, which it claims will be carbon dioxide negative during its lifetime.
The project in Skellefteå is built of a combination of cross laminate (CLT) and glued timber (glulam) and includes a theater, gallery, library, museum and a hotel.
The project follows a promise from 2020 by the Swedish architectural studio that every building it designs in 2030 is carbon neutral.
Sara Kulturhus Center was designed to be a landmark in the city, located just south of the Arctic Circle in northern Sweden.
“We designed Sara to become a landmark in Skellefteå, which marks the city’s most central location,” says White Architects partner Robert Schmitz.
“The building is planned to give life to the city center, open on all sides to show both public spaces but also the work behind the scenes,” he told Diéen.
The pulpit building contains Skellefteå Art Gallery, Museum Anna Nordlander, Västerbotten’s regional theater and the city library on its lower levels and is topped by a 20-storey hotel.
With a height of 75 meters, it is the world’s second tallest solid timber building, only 10 meters shorter than the 85 meter high Mjøstårnet building by Voll Arkitekter in Brumunddal, Norway.
“Sara is an open and accessible cultural center that brings together four cultural institutions with a hotel under one roof where they can work together,” says Schmitz.
“The building consists of a series of volumes of varying transparency, which reduces the scale from the existing buildings up to the tall building facing the square.”
The wood used in the building separates twice as much carbon as the incorporated carbon emitted during the building’s construction, the architect claims.
The studio performed a 50-year life cycle analysis that took into account the embodied carbon emitted during the building’s construction and operation, the carbon excreted in the timber and the emissions during the building’s lifetime.
They also took into account the amount of new timber that will be grown during this period to conclude that the building as a whole removes more carbon than it emits.
“Embodied carbon dioxide emissions from materials, transportation and construction as well as carbon dioxide emissions from operating energy for 50 years are less than the carbon dioxide sequestration in wood in the building,” Schmitz explained.
“That’s why we claim the building is carbon-negative.”
White Arkitekter carried out a 50-year life cycle analysis which claims that Sara Kulturhus Center will have a lifespan of at least 100 years.
“In terms of life cycle assessments, new trees must be planted to replace those harvested for the cultural center in order to be counted as carbon dioxide sequestration,” he continued.
“New trees will grow during the life of the building. That is why we refer to the 50-year life in our calculations.”
White Architects chose to design the building’s structure of constructed timber to take advantage of locally grown timber, which was processed at a sawmill about 30 miles from the site.
“We chose to work with a wooden construction to make the building as sustainable as possible, as the forest is an abundant local resource and to build on the local wood knowledge and tradition from centuries-old houses to contemporary constructed timber,” explained White Architects partner Oskar Norelius.
“The structure is exposed to show the construction and shape the interior,” he told Diéen.
While the structure of the tower was entirely made of CLT, the studio combined CLT with glulam pillars and beams to create the large open spaces needed for the cultural buildings on the lower floors. Steel structural elements were also used to create the spans required for the theaters and the large open foyer space.
“The building is designed with material optimization in the center, with the right material in the right place,” says Norelius.
“For the large span of the foyers, we have designed tailor – made trusses where wood is combined with steel. Given the different hybrid systems for tiles, the final construction is almost entirely made of wood.”
A geothermal heat pump and 1,200 square meters of solar panels on the building’s roof will provide the building with most of the power, while the rest will come from renewable sources.
White Architects hopes that the building will show how the carbon dioxide impact of buildings can be reduced or denied.
“Our goal has been to create a building that fully serves its purpose as a living cultural center with minimal impact on the climate,” says Norelius.
“Reaching carbon dioxide negativity means that this is a major step towards a more sustainable construction industry, while building a larger city and exciting spaces for people,” he added.
“The building, as a landmark in the city, it was important to create an exhibition for sustainable construction.”
At a Dezen lecture in Stockholm in 2020, White Architects’ CEO Alexandra Hagen promised that every building that the studio designs after 2030 will be carbon dioxide negative.
“At White Arkitekter, they have promised that by the end of the decade, all our projects will be carbon neutral,” says Hagen.
“Climate change is the most important challenge for the future during this decade,” said Hagen, who is the judge for the 2020 edition of the Disneyen Awards.
“We know that the materials used for products and for buildings are the main cause of carbon dioxide emissions,” she added.
“So we have to use our abilities as designers to transform into a circular economy.”
The photography is by Patrick Degerman, unless otherwise stated.
Client: Skellefteå municipality
Entrepreneur: HENT AS
Architect: White Architects
Civil Engineer: Dipl.-Ing. Florian Kosche, TK Botnia, WSP
M&E Engineer: Incoord
Lighting engineer: White Architects
Sawmill / CLT / GLT: Martinsons Trä AB
Module manufacturing: Derome