Energy-saving housing estate

As owner with a facade thermal insulation and supplementary measures to meet the prescribed requirements and to benefit from them at the same time.

Sustainable city development

All in all, the energy and aesthetic upgrading of the Ossendorf housing estate based on an ecological concept of measures is an effective contribution to the sustainable development of the city district. "What previously gave the impression of a suburban ghetto is now becoming the new centre of Ossendorf," explains Günter Ott (board member of investor), not without pride. "The colour concept, completely redesigned outdoor facilities as well as paths and squares give the estate a whole new look and ensure that residents feel at home here. If they can save money on the bottom line, that's all the better." In fact, the residents of the Ossendorf housing estate are not the only ones to benefit from the upgrading of their residential environment. Two years ago, the monthly costs for hot water and heating were still around three Euros per square meter. "Today, the charges are only 0.21 Euro. That is a reduction of more than 90 per cent," explains Günter Ott. "So, the rent increase maximum of two Euros per square meter is more than offset by the reduction of energy costs."

Comprehensive state funding

The energy-saving housing estate in Cologne-Ossendorf is a worthwhile investment not only because of the durability of the ETICS, the enormous energy savings and the noticeable increase of property value. In addition, the investor GAG Immobilien AG was also able to take advantage of the extensive subsidies of the federal and state governments. The state of North Rhine-Westphalia (NRW) alone supported the project with 300,000 Euros as part of the 50 solar-energy housing estates within NRW programme. In addition, there were low-interest loans and a repayment subsidy from the CO2 building renovation programme of the German Federal Promotional Bank (Kreditanstalt für Wiederaufbau = Reconstruction Loan Corporation) as well as various subsidies for alternative energy sources.

High-quality facade design

A mineral fine-grained render is particularly durable and consists of purely natural raw materials. It is therefore particularly suitable for an ecological renovation project, like the Ossendorf energy-saving housing estate. Scratch render surfaces are hydrophilic, i.e. they absorb rain or dew water and quickly release it again. In this way, they offer lasting protection against algae and fungi, which makes the use of environmentally harmful preventive or cleaning measures unnecessary and ensures long-term value preservation. In addition, the rather sober and functional 1960s buildings of the Ossendorf housing estate also experience a considerable visual upgrade thanks to this type of surfaces. The originally grey facades now shine in modern and friendly shades of red and yellow. The lively surface texture characteristic of scratch render further emphasizes this appearance.

Ecological insulation

For the facade insulation, the external thermal insulation composite system weber.therm A 100 consisting of mineral wool lamella boards and mineral top coat renders was used. The 14-centimetre thick insulation layer by itself reduces the energy consumption of the Ossendorf housing estate by around 40 percent. In addition to the excellent insulating properties, the system features are a high permeability to the diffusion of water vapour as well as maximal fire protection (reaction to fire A 1: non-combustible). In order to fully exploit all these advantages, all the individual components specified by the manufacturer of building materials Saint-Gobain Weber were exclusively used within the whole system build-up. A thick-layer mineral scratch top coat render was used for the surface design.

Exemplary project

"Nothing is as convincing as the built example. GAG's renovation project in Cologne is exemplary," was the comment of the Minister for Economics Christa Thoben on the sidelines of the inauguration ceremony. In fact, the completed apartment blocks are absolutely trend-setting in terms of heat supply and thermal insulation and also meet all the requirements of an all-round ecological construction method. For example, the electricity supply and water heating are largely covered by solar thermal and photovoltaic systems. However, such a climate-neutral heating concept only makes sense in combination with high-performance, eco-friendly thermal insulation.

Save money with climate protection

On 1 October 2009, the new version of the Energy Saving Ordinance comes into force. "In this context, the housing industry in particular will be held to an even greater obligation than before," explains Christian Poprawa, marketing manager of the manufacturer of building materials Saint-Gobain Weber. "For example, it is planned to increase the requirements for saving energy in new buildings and modernizations by 30 per cent. A further tightening of the same scale is to take place in 2012." The fact that such requirements can easily be met is demonstrated by the largest energy-saving housing estate in North Rhine-Westphalia. In the Cologne district of Ossendorf, the investor GAG Immobilien AG has modernized a residential estate built in 1963 with the help of high-quality thermal insulation and a central wood pellet system, and will thus save up to 90 percent of heating costs in the future.

Building site:
Energy-saving estate

Project type:
Residential flats