As social and economic developments take place in ever-shorter cycles of change, buildings should also be adaptable to change and not be geared solely to planned use.
Buildings can be used and valued for hundreds of years. The load-bearing components in particular influence the durability and reusability of buildings.
The cost of constructing or refurbishing buildings is the smaller part of the lifetime expenditure compared to operating costs. Therefore, the life cycle cost principle is an essential part of sustainable construction. In addition, space efficiency and adaptability are important aspects of an economic assessment.
Economically optimised planning is based on a fixed period of time as a reference. This means that costs incurred during the use of buildings - for example for heating, cleaning or the renewal of floor coverings - can be estimated and compared with the construction costs. For the Assessment System for Sustainable Building (BNB) of the Federal Ministry of Building, a period of observation of 50 years was defined, as most buildings are used for more than 30 years. This is an appropriate parameter for estimating the costs of long-term building operation and corresponds to an annual renewal rate of the building stock of 2%.
Planning based on life cycle costs, flexibility and adaptability must focus on the following points in particular:
- Development of a ground plan and building structures that offer the best possible functionality for the construction task. Implementation of building qualities that are optimal in terms of functionality for health, comfort and working efficiency of the users.
- Building design from a cost point of view using optimisations to keep risks and operating costs low throughout the life cycle.
- Minimisation of energy demand and energy costs - also taking into account costs for maintenance and renewal of technical systems
- Use of building materials and components that are durable, easy to maintain and clean
- Measures to reduce the demand for drinking water
- Flexibility / divisibility into different usage units, consideration of axis grids, use of lightweight partition walls, etc.
- High space efficiency