Mar 23 2009
The detached wooden houses so typical of Scandinavian countries are an attractive complement to their surroundings and - what’s more - are also made using a natural product - wood. However, in the depths of winter, a lack of heat insulation can make getting close to nature a lot less enjoyable and send heating costs soaring.
Now, in Norway, new energy conservation legislation has been introduced which calls for a substantial reduction in energy consumption. A particular challenge with wooden dwellings is that heat can escape rapidly through the chinks between the timbers. MjøsCon AS - a subsidiary of Mjøsplast AS based in Moelv, Norway - has been working in cooperation with Bayer MaterialScience’s Nordic BaySystems polyurethane systems house in Otterup, Denmark, to develop an intelligent solution for the year-round usage of wooden houses. This is based on polyurethane rigid foam, which has the highest insulating capacity of any material on the market. If conventional insulating materials were used, walls would have to be made much thicker, and windows smaller, in order to achieve the same level of heat insulation. The adverse effects of this would be reduced living space and less natural light.
With the MjøsCon system, two wooden beams - one with a cross-section of 98 by 47 mm, the other 40 by 47 mm - are placed in a mold and the space between them is filled with a liquid polyurethane system consisting of Desmodur® 44 V 20 L and Baydur® C-77-B-60/W. The mold is then sealed and the composite material is cured at a temperature of around 45 ºC. The polyurethane system adheres extremely well to the wood substrate, thereby ensuring that the composite is also mechanically stable. The finished wood/polyurethane beam can be removed from the mold after only a short time. With the addition of the 60-mm-thick layer of polyurethane rigid foam, the composite timber now measures 198 by 47 millimeters. This technology helps to significantly improve heat insulation. Most importantly, thermal bridges between the interior space and the exterior are prevented. The inventors have applied for patents for the product and production process. The Norwegian Industrial Property Office has given a written reply that the invention will be patented. So far, the solution has been used to insulate a detached house in Trondheim and work on another building at Høvik, Oslo is soon to be completed.
MjøsCon recently won the prestigious DnB Norway Innovation Award in the New Creativity category for the development. The award panel said the development demonstrated outstanding expertise and had the potential to set new standards in the construction industry.