Consultants: iTre, Høyer Finseth, Rambøll, Vintervoll, K.Lund, Brekke og Strand
Client: Studensamskipnaden I Trondheim (SiT)
Text description provided by the architects. The student towers are a part of a larger masterplan densifying an existing student village in Trondheim, Norway. The project uses the site of a former parking lot to create a new heart for the student village with housing units, kindergarten, grocery store and sports activities. All buildings are planned in cross laminated timber (CLT).
In the original competition proposal the towers were envisioned built with conventional construction methods; a steel and concrete structure with a brick cladding. The latter in order to harmonize with the existing low-rise student housing with redbrick facades. To meet the project's ambitious energy and climate goals the project team researched the possibility of turning the structures into cross-laminated timber constructions (CLT). The towers, with their relatively short spans and Y-shape volumes, were in many ways statically optimal for CLT-construction.
The five towers are 9-storey high buildings with a height of 28-metres. The basement and ground floor levels are made in reinforced concrete cast in-situ. From the first floor to the 9th floor the entire structure consists of prefabricated CLT-elements. Elevator shafts and stairwells are also constructed in CLT. Both inner and outer walls are structural.
The approach to building with CLT was to take advantage of the finished surface of the CLT elements and expose as much as possible of the CLT element system by developing a robust and honest detailing concept. The joints of the structural elements are revealed as part of the aesthetics of the interior.
A full scale fire test was conducted to establish a better information basis for fire sizing, burn rate and sprinkler capacity. Plasterboard, screed and insulation are used in some of the ceilings and walls to obtain structures in accordance to fire and sound regulations. Some of the structural walls, for example the insides of the staircases, are painted with a transparent fire protecting wood stain that enables the exposure of the wooden surface.
Like regular wood structures, CLT wood structures have the characteristics of shrinkage in tangential and radial direction. The façade cladding system of the student towers is designed to give it a telescopic characteristic, which can absorb the shrinkage of the floor elements without creating tensions in the cladding. The façades are clad with Kebony treated pine wood panels, a sustainable softwood product, environmentally processed with a bio-based liquid. The Kebony cladding on the ground floor is treated with a fireprotecting wood stain, whereas the rest of the Kebony façade is left untreated and will weather naturally.
The project is built with passive house energy standards. The use of CLT has reduced the CO2 production in building materials by 57 % in comparison to traditional construction methods. The structures are heated and cooled with geothermal energy.
The project is nominated to the Mies van der Rohe Award 2017.