Foto: Wohnzimmer- Haus Zeggele

Architecturally Diverse, Energetic Renewal

Post War Modernist Buildings Under Monument Protection. A Comparative Analysis of Energy Efficient Renewal
Case study: Open Air School Franklinstrasse, Wien 21

Content Description




The main purpose of research was to develop a renewal/preservation proposal which combines landmark preservation principles with enhancement of energy efficiency and energy performance in Modernist buildings. An alternative preservation method was designed as a unique solution for the particular case study. The methodical approach of the alternative practice can however be seen as an exemplary solution for restoration of similar buildings of the same era.

Our idea was simple: when authentic building parts (i.e. thin steel frames and glazing) and the style of the early sixties modernism are to be preserved and a reasonable energy standard for the building as the whole is to be achieved, other building parts have to be outfitted with enhanced energy standard in order to compensate. We named this method of renovation "Architecturally Diverse, Energetic Renewal". In the course of our research we compared the "ADE - Renewal" method to the "classical" method of energetic renovation. The comparative analysis contains energy data, cost of construction and energy expenses of both methods.

Chronological procedure:

  1. Assessment of present condition of the school building "Sonderschule Floridsdorf" (School for pupils with special needs)
  2. Research and analysis of building typology
  3. Research and comparable study of similar, already renovated buildings
  4. First proposal for the alternative method, definition of building modules und parts.
  5. Definition of preservation measures for each of the building parts
  6. Preliminary catalogue of restoration measures as "Architecturally diverse, energetic Renewal" (ADE-Renewal)
  7. Assessment of energy efficiency for "classical" renewal and ADE-renewal. Comparison between the two models
  8. Adjustment of measures in the ADE-renewal concept according to energy analysis
  9. Cost estimation for both restoration methods
  10. Documentation of present condition, already carried out restoration measures and proposed measures according to ADE-renewal.
  11. Development of an assessment method for preservation method evaluation

Methodical inventory of all building parts is essential. Especially the parts that are crucial for the architectonic building conception have to be well documented, both in their present state and according to original design or originally intended state. The measures for essential parts of the building were chosen very carefully, for every historically relevant part an own restoration plan was developed. Which parts and elements should be preserved, which parts are to be renewed or reconstructed? What kind of material and which forms can be used? Which energy value should certain parts achieve in relation to their purpose and their location? These questions were guidelines for treating the relevant building elements.


Assessment of energy efficiency

  • Comparison of "classic " method of energy renewal to ADE renewal:

    Due to the measures of the "ADE-renewal" method as compared to "classic " renewal we were able to enhance the energy efficiency of every building module. For the entire building (ADE renewal) in accordance to gross square area the value of 41 kWh/m²was calculated. This means a reduction of 48 % in comparison to "classic" renewal method. The study proves that restoration proposals with measures which obey the principles of landmark preservation, enhancement of energy efficiency is possible as well, with good overall results.

  • Findings according to cost assessment

    Austrian norm Ö Norm B 1801 was the basis for cost estimation. The result of comparison of building costs for both methods was the realisation (that somehow confirmed the expectations) that the ADE renewal plan is more costly than the "classic" way. The difference, however, turns out to be moderate. ADE renewal plan is 25 % more expensive than the "classic" one. In our opinion this outcome is a good result.

  • Method of assessment for renovation conceptions

    The following criteria were used for assessment of both methods (The importance of each criterion is expressed in percentage points):

    1. Preservation of original elements/materials: 10 %
    2. Preservation and/or reconstruction of original architectonic conception 15 %
    3. Cost factor 50 %
    4. Energy efficiency / enhancement 15 %
    5. Usage of ecologically sensible materials 05 %
    6. Restoration of original colour scheme 05 %

Renewal conceptions that combine several aspects of restoration achieve good scoring in the proposed assessment. The method of assessment is to be used as a guiding scheme for simultaneous application of different motives in one proposal.


Developing sensible restoration proposals for Modern Movement and postwar modernist landmark buildings and carrying them out is a new terrain on which further research und development are necessary. Methodical approach and an attitude of improvisation and innovation are vital when dealing with this kind of buildings.

Both landmark preservation measures as well as the enhancement of energy efficiency can be combined successfully in one renewal proposal.

The outcome of our research is summarized in one such proposal, which unites several different measures of renewal. The "ADE" renewal proposal proves the following: combining several aspects and motives such as preservation and reconstruction of original concept and authentic elements / materials and at the same time achieving good energy standard is possible. This alternative renewal proposal is only moderately more expensive than the "classic" way of renovation.

Future oriented restoration proposals should take into consideration and combine several aspects of renovation and improvement, i.e. preservation and when necessary reconstruction of architectonic conception, the enhancement of energy efficiency and lowering energy consumption costs, overall investment costs, application of sustainable technologies, usage of ecologically sensible building material, etc. Due to committed planning it is possible to unite several restoration priorities in one proposal and thus prevent technocratic solutions and one sidedness.

Project Partners

Project manager:

Arbeitsgemeinschaft Dipl.-Ing. Gerhild Stosch and Arch. Dipl.-Ing. Maja Lorbek


Dipl.-Ing. Gerhild Stosch,
Diehlgasse 50/28
A 1050 Wien
Tel./Fax: +43 1 548 17 47

Arch. Dipl.-Ing. Maja Lorbek
Schottenfeldgasse 72/2/6
A 1070 Wien
Tel./Fax: +43 1 526 38 41

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