This black prefab house was a project by Lars Frank Nielsen of the Danish Studio Onen. The One+ is finished for a Swedish company Add-A-Room. The house can be used as an addition to the existing house or even a small home for weekend or summer holidays. The house measures only 15 square meters per module and is made of high quality local materials and it is also energy efficient. This small home could provide several basic rooms, which make it ideal for guest room or summer house. The house is usually delivered by the company via truck and it is installed via crane on your site. Each of the modules is sold from $35,000 and you can contact Add-A-Room for more details.