Skanska was contracted by municipal housing company Ramunderstaden to construct an Ecolabeled four-story building containing 16 rental apartments in Söderköping. The building is Skanska’s first Ecolabeled residential building. The building, which was constructed under the ModernaHus concept, is highly energy efficient, has a low environmental impact and uses materials that contain as few environmentally harmful substances and substances that are hazardous to health as possible.
ModernaHus focuses on efficient and industrialized construction and offers a shorter project planning and construction period compared with traditional construction projects. Skanska was the first in the Nordic region to receive an Ecolabel license for residential buildings under the ModernaHus concept.
Instead of constructing the building on site, the framework and façade are cast in Skanska’s plant in Strängnäs. Other parts of the building, such as the bathroom, windows, ducts for electric cables and junction boxes for power points and circuit breakers are prefabricated at the plant, all to enhance the efficiency of the construction process. Once the prefabricated parts are completed, they are transported to the site where they are assembled. Traditional foundation work must be performed before the actual module assemble stage. The land conditions in Söderköping were difficult and a 39-meter bore depth, 50 holes and 150 piles were needed to create a very stable foundation.
After the foundation was laid, work on the structure began. The first prefabricated framework parts and façades were delivered to the construction site in August. Once on site the framework parts were assembled, rather like a large Lego set. Assembly of an entire floor could be done as quickly as in two and a half days.
But it is not only the quick assembly process that makes ModernaHus so successful. The heating can be turned on as soon as the roof is in place. The rapid assembly process also means that exposure to damp and moisture is minimal compared with a normal construction process. In Söderköping, the drying process was significantly shortened compared with a traditional construction process and neither construction fans nor current were needed.
The dry phase can start as soon as the roof has been assembled. This phase involves the assembly of interior walls, painting, floor-laying and building the kitchen.
Another advantage of ModernaHus is that the construction site is kept clean and structured. Waste is also markedly reduced and the amount of material that needs to be transported to a landfill is minimal.
With the shorter project and construction time, the property owner can also start generating income more quickly. In addition, ModernaHus’s energy consumption is between 25 and 50-percent lower compared with the levels prescribed by the Swedish National Board of Housing, Building and Planning’s Construction Standards.