Life-cycle optimised housing

Performance approach aims at management of a product's life cycle properties, and benefit for the users. In eco-efficient construction, performance is an output value achieved with certain input by environmental impacts and life cycle costs. Market driven life-cycle optimised construction has to fulfil three major requirements. A performance that fulfils the user requirements for extended periods should be the output from the design and construction process. Low environmental pressure and low life cycle costs are the input needed to fulfil the requirements. As decision-making is often based on first costs, the building's technical solutions need to be cost-effective. Based on performance requirements set for indoor climate, comfort and adaptability to user's varying needs on one hand and requirements on first costs, life cycle costs and environmental impacts on the other, a model house introducing a new wooden structural system was designed. The architectural challenge of the model house comes from the high adaptability of interior and exterior spaces including a possibility to expand the house according to future needs. The analysis of the model house shows 60% reduction of heating energy consumption and 30% reduction of life cycle costs compared to a typical house. According to call for tenders, the investment costs are on the level of a typical house. The building introduces a new open wood-framed building system Nordic Platform allowing for shorter delivery cycle than with typical site-construction. The system aims at site-construction from pre-fabricated products for building envelope. The open construction system with published structural details is free to be copied by other network actors. As the basic principle of the construction process is to utilise local enterprise networks, resources and labour, education for both producers of building products and site-workers is needed. Special features of the system are 250 mm single-frame wooden structure with integrated thermal break for exterior walls and trussed construction for internal floors. The house has a mechanical ventilation system with heat recovery. Two heating systems are introduced: floor heating and ventilation heating system. The house is also designed for regional construction and distributed energy supply. Trussed floors include a possibility for easy and flexible installation and maintenance of building services systems.