Life-cycle-cost optimised wooden multi-storey apartment building

The aim of this project was to develop a concept of a wooden multi-storey apartment building which is competitive with equivalent buildings made of other materials. The point of view has been that of the house owner, the investor. He is interested not only in the investment costs but also in the operating costs as well as in the resale price of the building. In this research, the life span of the building is limited to 50 years. The wooden multi-storey apartment building has to be not only competitive to build but especially clearly cheaper to operate. The Finnish statistics show that about 2/3 of the operating costs come from energy, management, water and annual repairs. The major components, about 3/4 of the annual repairs are exterior surfaces, mechanical systems and interior surfaces and structures. Thus, the research has concentrated on developing and analyse long-lasting wooden facades and life-cycle cost optimised envelope structures. Simplifying and decreasing the number of various components has proved in other industries to be an effective way of decreasing the investment and operating costs, and this is true also in the construction industry. And last but not least, the overall quality of the wooden multi-storey apartment building should transmit a positive image to the owner and the tenants of a better product than that of the competitors. The results of this research work show that the main properties of a life-cycle-cost optimised wooden multi-storey apartment building are as follows: • The investment costs of a wooden multi-storey low-energy apartment building are some 4 % higher than those of the present building practise. Due to lower energy costs, the payback time of extra investment costs is only 15 years when calculated using present energy prices • The "high performance" facade is more profitable than a "normal" one. There are various alternatives for "high performance" facades. The main factor for the durability of the wooden facade is "wood-paint-structure-environmentmanufacture". When all these factors are optimised, a long lifetime can be achieved