Ermittlung der Bauwerkskosten mit Standardraumstrukturen im Wohnungsbau in frühen Phasen der Immobilienentwicklung

摘要

The economic success of a real estate project needs to be assessed at an early stage of the development process.The decision to realise a project is based on uncertainties such as the planned project costs, the expected rental income and the type and degree of utilsation to which it will be used. A real estate object comprising a building structure and a site (property) is unique at the highest level. The building can, however, be composed/concatenated from non-unique components and rooms assigned to/specified for different types of use. The size and equipment of these components and rooms are known from completed projects, as they have already been planned and built numerous times. This information is used to determine building costs by defining standard room structures on the basis of room functionalities containing information down to item level, which is normally only available from the execution planning.This is a theoretically and practically sound model whose cause-effect relationships have been derived quantitatively and confirmatorily.The input variables are to be specified by the developer according to the functional operation. Composing the entire building from standard rooms leads to a detailed building target content at item level including item-related quantities. As a result, the model provides all building cost broken down according cost groups and service areas. Future investment costs are also determined by linking the respective items to the lifetimes of the associated components. This allows the developer to optimize the entire building beyond the production costs on the basis of life cycle cost. The following article is intended to provide a summary overview of this methodology and its applications in recent years.