Verksbyen will become home for 5000 people within the next 10 years. It aims to be Norway’s most innovative housing project. In the long-term, the developer, Arca Nova Bolig, has ambitious plans to change the housing market much in the same way as Tesla has changed the car industry. It is a bold claim, but it strongly believes in growing demand for sustainable building, which is the backbone of the Arca Nova’s Future Living concept.
CEO of Arca Nova Bolig (part of the Arca Nova Group), Ruben D. Hansen, said: “We have managed to reduce CO2 emissions in a variety of ways. The houses are built with timber elements according to the Passive House standard. Electricity is produced with solar energy and heating with solar thermal energy. Smart house technology with voice control adds an extra touch to all of this. As a result, the inhabitants will not only live sustainably but enjoy reduced living costs too.
Fast, light and green construction
Metsä Wood has worked in close partnership with Arca Nova Bolig to assist with its technical solution for the wooden apartment buildings. The cooperation has been vital to the success in creating a new design system for the Norwegian housing market.
Using prefabricated elements has proved to be an extremely quick and efficient way to build for contractor Arca Nova Entreprenør. The buildings are rising at the pace of one floor a week, which has allowed the company to complete an entire building in just five weeks.
The first of the five multi-storey buildings have already been completed, with the remaining scheduled for completion by the end of 2020.
It is easy to understand why Arca Nova Bolig and Metsä Wood make such great partners. Hansen highlights the lightness and load-bearing capacity of the Kerto LVL products. Building with sustainably-sourced wood is also an environmentally-friendly and sustainable way to build now and in the future.
“Constructing with prefabricated elements using Kerto LVL products enables us to reduce both building time and CO2 emissions quite substantially compared to the traditional way of building with steel and concrete. Also, the dimensional accuracy of Kerto LVL is a benefit, as the materials do not shrink during construction,” says Hansen.
The wall elements for the first building were produced by Punkaharjun Puutaito in Finland, and the floor elements have been produced by a Finnish company, VVR Wood. For the next buildings, Arca Nova Entreprenør will carry out part of the element production at its own factory in Estonia.
Load-bearing structure
The roof and floor structures in the project are based on the Kerto-Ripa system – an enhanced design system for roof and floor elements, developed by Metsä Wood. Based on Kerto LVL S-beam and Kerto LVL Q-panel load-bearing components and structural gluing, it enables the elements very long spans, up to 20m, making it possible for structural designers to remove columns and increase design flexibility.
Kerto-Ripa-designed elements can be of both open and closed structure and insulated to match every unique buildings’ exact requirements.
In the first three floors of the Verksbyen project, the load-bearing structure consists of wall elements, which are made with 67mm-thick Kerto LVL Q-panels. In addition, Kerto LVL S-beams have been glued and screwed on the outside of the elements to stiffen and stabilise the construction. The S-beams are also used for installing an insulation layer. In the two top floors, there is a traditional timber frame construction reinforced with CLT plates to take up the loads.
“We have a stiff, yet elegant and slim structure, which transfers the heavy wind, snow and seismic loads to the foundation made of concrete,” said Hansen.
The intermediate floor consists of elements, which form a stiff plate to transfer the loads to the end walls and the walls in between the apartments. Each element consists of Kerto LVL Q-panels on the top and Kerto LVL S-beams as ribs and bottom flange. The unique structure allows floors of up to 9m in open span.
Strong connections
Various steel plates and parts, bolts, screws and glued-in rods are used together with the floor and wall elements to create a stiff, stable and massive construction.
The wall elements of these multi-storey buildings are connected with bolts to steel plates on the bottom, and the beams are assembled in between the elements with strong steel angles. The frame is connected to the floor elements with adjacent steel parts and massive bolts.
Highly fire-resistant materials
The multi-storey apartment buildings are built according to strict fire safety regulations, with a modern sprinkler system installed.
The exterior walls are constructed as R90 walls, and the intermediate floor elements are constructed as REI60 floors. Part of the fire concept is the massive use of Kerto LVL, which provides 60 minutes of fire resistance, which is combined with gypsum boards to provide fire protection layer in the floors.
Long-term cooperation
Arca Nova was keen to develop its own construction concept to build tall timber apartment buildings and was impressed with Metsä Wood’s Kerto-Ripa design system.
“They have supported our learning with their help and knowledge. It was great to visit Metsä Wood’s mill and see showcase buildings in Finland. Our cooperation has been vital for our success to create a new design system for the Norwegian housing market,” concludes Hansen.
