In Vienna, around 35,000 buildings, corresponding to around a quarter of the main residential units, were built between 1961 and 1980.
Social housing buildings from this period are an essential backbone of the city’s rental housing stock.
Across Austria, there are around three times as many buildings from this period.
A typical construction element of this type of building are curtain wall façade elements made of exposed aggregate concrete panels or metal sheets.
The ageing buildings are in urgent need of comprehensive thermal refurbishment, which must be efficient, affordable, technically feasible and scalable and, if possible, should be carried out without interfering with the occupied rental units.
This is the only way to achieve a rapid increase in refurbishment rates in the interests of climate protection.

Currently, façade renovations are usually carried out using external thermal insulation composite systems (ETICS) with EPS insulation.
The existing façade elements made of exposed aggregate concrete or sheet metal are dismantled and disposed of together with the windows, which leads to environmental pollution through transportation and landfill as well as the loss of resources of these valuable building materials that are suitable for further use.

The exploratory project “Favorite Facade ReUse” aims to develop an innovative, technological solution for the refurbishment and thermal upgrading of curtain facades that allows the continued use of existing facade elements and at the same time uses the facade construction in a new way for heating, greening and possibly as a design surface.
Refurbishment is carried out from the outside, residents are actively involved.

Five partner organizations will contribute their interdisciplinary expertise to the exploratory study, including the architects Jutta Wörtl Gössler (project management) and Uli Machold, TU Vienna / Institute for Materials Technology, IBO Institute for Building Biology and Ecology and the innovation laboratory RENOWAVE.AT.
For the subsequent demonstration of the exploratory results, the non-profit property developer GESIBA was won as a project partner, which has over 40 identical properties of this type with more than 5,000 residential units and will renovate one of these properties as a demonstration case using the newly developed façade renovation strategy on the basis of the exploratory results.

Building on the knowledge gained from individual reference projects, Favorite Facade ReUse has set itself the goal of developing an integrated overall concept for facade refurbishment for the first time.
In an innovative refurbishment strategy, individual measures are combined and optimized (reuse of façade elements, sustainable insulation, integrated surface heating, upgrading of windows and greening measures) are analysed and simulated in order to achieve a high climate protection effect through the best possible resource savings and energy-efficient refurbishment.
Compared to conventional façade renovations, CO2 savings in the order of 40% are expected.

In view of the large number of residential buildings of this type, there is great potential for climate protection.
The cooperation with GESIBA and an intensive transfer of knowledge will support rapid replication.
Re-using the original façade elements will preserve the authenticity of the existing buildings, value the craftsmanship of the façade design and increase the attractiveness of the renovated existing buildings and districts as living spaces in the climate-neutral city of the future.