Today´s roofing of dwelling houses is a very time consuming procedure, which includes a lot of different steps on the construction site. Not only does it cost a lot of money, but often do problems with rot and mold occur in the attics of houses today. The use of prefabricated modules has seen a great breakthrough in the field of construction of dwelling houses; at least when it comes to foundations and walls, where this type of approach makes the construction process way more efficient. What no one previous has succeeded to develop is a corresponding system for roofs that meets the demands of a dwelling house. Accordingly the goal of Plustak has been to come up with a proper module system for roofing of dwelling houses, where the roofing is completed to meet the demands of the Scandinavian market. During the project a lot of effort has been put into customer contacts and the usability of the product, as well in the manufacturing process as on the construction site. This development has gone hand in hand with several practical tests and tryouts.