facade4zero - Entwicklung ressourcenschonender Fassaden unter dem Gesichtspunkt der Nachhaltigkeit als Alternative zu WDVS

The aim of the facade research project facade4zero is to develop a fourth-generation facade. Man-made structural envelopes have passed through three major stages of development in the past: 01. The main purpose of the first structures was protection from the weather. 02. The next stage began with conscious design of the envelope that took visual aspects into account. 03. Due to the energy crisis in the 1970s, the third step was towards reducing heating energy by means of thermal insulation. 04. Triggered by the climate change debate, the construction industry has for some time been exploring the topic of sustainable building. This ushers in the next, and thus the fourth stage of development: the aim of the facade research project facade4zero is to develop a sustainable, efficient successor for the currently predominant exterior insulation finishing systems. As one of the market leaders in exterior insulation finishing systems (EIFS), STO is thus the ideal partner for developing and introducing such a facade system on the market. The name of the project is the fourth-generation facade, Facade Four Point Zero. The 4.0 included in the title is thus to be seen as the first version of the next generation of facades. facade4zero combines design qualities such as appropriate surfaces (textures) and a high level of variability with the simplicity of EIFS in terms of installation, adding the characteristics of sustainability which will become increasingly important in the future. The aim is to achieve the following product properties: - an alternative to conventional EIFS - sustainability and positive assessment of the entire life-cycle (including profitable separation, disposal and recycling) - reduction of costs thanks to simple and fewer installation steps - positive recycling behaviour of building components at the end of the period of use (recovery of resources) Development ideas approaches to development: - total energy balance and holistic consideration (recycling life-cycle) - anchoring to wall elements installation with thermal separation (no thermal bridges) - coating with transparent foils (in combination with photovoltaic systems) - addition of StoVerotec rear-ventilated facade systems - economy: cost/benefit in competition Both Sto and the Institute for Architectural Technology are aware of the necessity that the consequences in terms of design take priority in developing a new system. The aim of the facade4zero research project is to lay the foundations for a fourth-generation facade system with the potential for general use, that permits a maximum range of applications in architectural design thanks to its structural make-up. A crucial factor for the subsequent commercial success of this system, alongside freedom of design and ease of planning, is cost efficiency in production, maintenance and disposal of the complex facade. Also highly relevant are factors such as the total energy balance of the system, simplicity of installation and maintenance, and longevity. The main objective of developing the new facade system is therefore to ensure full recycling capability of the building materials without any additional costs or increased maintenance. What is the state of the art? The challenge to be solved in this project of creating a sustainable facade system consists in the complexity of the subject. Several reasons are listed below in view of the complexity of the current success of exterior insulation finishing systems: EIFS can be used in new buildings and when thermally refurbishing old buildings. Production of EIFS is inexpensive and its components are easy for tradesmen to install. As a popular, established system, it is recommended by tradesmen, which serves to multiply its success. The limitations in terms of design are few, and hardly anything needs to be considered when planning in this system. However, users are hardly aware of the drawbacks either. The project is divided into three phases: 01. Research and analysis and development of the system 02. Review of the system, construction of prototypes 03. Approval for certification The first phase consisted of extensive research and analysis with regard to the requirements to be met by a facade system so as to review the formulated objectives on this basis and to be able to develop the facade system in keeping with the demands of the target market. Research includes a survey of products and visiting the STO production and research sites, and practical application of EIFS in Stühlingen. A specially developed survey formulated potential questions and problematic aspects concerning applied facade systems and questions regarding wishes to be met by exterior insulation finishing systems (EIFS). This questionnaire was sent to architectural firms in the German-speaking countries. The result of the study is that EIFS are preferred for reasons of costs, but that there are disadvantages with the less expensive systems in terms of sustainability, longevity, and renewable raw materials. The result of the analysis is the realisation that system longevity and maintenance requirements still have potential for development. Also, there is considerable work still to be done on accessibility and creation of data with regard to the production energy and total energy balance of building materials. In assessing primary energy and greenhouse potential, there are still no standardised, comparable building material energy benchmark units. Comparability of building products is long overdue, but is also a complicated procedure. The online database of building products, the DGNB Navigator (Deutsche Gesellschaft für nachhaltiges Bauen e. V.) is scheduled to go online in June 2011. Based on the catalogue of criteria of its certification system, the DGNB offers architects and planners relevant information on technical properties and ecological, economic and health-related aspects of building materials. For example, the DGNB system displays a clear classification of building products with regard to pollutants and hazardous materials. In addition, it provides life-cycle costs of building products as well as detailed life-cycle assessment data, e.g. from environmental product declarations (EPD). We are at the moment planning and reviewing our facade system with regard to these benchmarks. The current legal development concerning future amendments to the energy saving directive in Austria and Germany has so far yet to address the topic of sustainability as, according to current information, it still only considers energy consumption during the period of use. In view of public perception (cf. discussion on climate change), the results and publications of government-affiliated research agencies (e.g. IBO in Austria), the possibilities of calculation offered by modern CAD software during the planning stage (e.g. Autodesk Ecotect), and the criteria for building certification (e.g. the German quality mark Nachhaltiges Bauen from the DGNB), the use of a fourth-generation facade becomes a competitive advantage if, like EIFS, the new system has positive properties at many levels. first step was an analysis and brainstorming intended to draw up a large pool of ideas (with more than thirty potential ideas) with initial ideas for systems. At regular project meetings (milestones) the various results of research are presented, assessed, evaluated and reviewed. Feasibility and target market requirements are major factors with regard to further development. The second phase involved developing the concept for the facade system. Elaborating the concept also requires calculational proofs regarding structural properties and properties relating to building physics. Prototypes are then built on the basis of the theoretical development. Prototype production took place with companies in Stuttgart and at the Graz University of Technology. The production methods are laser sintering methods and LOM (Laminated Object Modelling), which are tested in laboratories and assessed with regard to structural engineering, weathering and suitability for installation. The third phase involves approval for certification of the system.