You can see at first glance that building with  system uses less concrete than conventional construction: The prefabricated concrete elements are much more delicate compared to conventional solid construction - with identical functionality. But we wanted to find out more.

The framework conditions

The differences to the conventional building principle lie primarily in the shell construction. External walls, internal walls, intermediate ceilings, roof, foundations, supports (internal and external), floor slab, stairs and staircase were therefore analysed. The concrete and reinforcement quantities of the ‘Cube’ were determined from the planning documents. The values for the production steps of the exterior wall elements and ribbed ceilings in the factory, including electrical and thermal energy consumption and waste from production (sewage sludge and concrete), are taken from our environmental management system.

The question

Which construction principle has the better CO₂ balance - in terms of production, dismantling and recycling potential? And: How much CO₂ does GOLDBECK save in the construction of an average office building compared to a conventional construction method? 

The task

A project already realised by GOLDBECK is examined in detail and our construction method is compared with the conventional construction method. The focus is on the building materials used for the shell construction. Raw material extraction, supply transport to the production plant, production, waste treatment and disposal as well as the reuse, recovery and recycling potential are analysed. In order to ensure an independent and unbiased view, we had the comparative building planned by an external engineering firm - using conventional construction methods. The respective carbon footprint was then calculated using GaBi and Legep - the standard software programmes for such tasks. To be on the safe side, we then had the results of the test checked again by independent experts. 

Our test object

The ‘Cube’ in Engen on Lake Constance. It is an office building that we built for our client Sachs Engineering near the A81 motorway.The key data: six storeys, 3,800 square metres, inside a mix of office workstations, conference and social rooms, plus a bistro and a hall area on the ground floor.The building bears its English name - ‘cube’ in German - because of its uniform edge lengths and symmetrical cubature.A typical GOLDBECK office building. We give our planning documents to the experts and start the comparison.

The result

The differences are significant. Thanks to the GOLDBECK construction system, the project saved a total of over 135 tonnes of CO₂ - the equivalent of more than one million kilometres driven by car and over 22 percent less than conventional construction methods.That's a saving of around 36 kilograms of CO₂ per square metre.If, in addition to production, dismantling and recycling potential are also taken into account, the GOLDBECK construction method even saves more than 25 per cent of the climate-damaging gas thanks to the building materials used.Over the entire period, this results in a saving of 41.5 kilograms of CO₂ per square metre compared to conventional construction methods.

What are the reasons?

Prefabricated system elements are significantly slimmer compared to in-situ concrete, as concrete of higher strength classes can be used and the system construction method leads to long-term optimisation: Only what is structurally necessary is constructed. We also use cement in which the energy-intensive cement clinker is partially replaced by energy-saving aggregates. Whenever it makes sense for technical production reasons, we use so-called CEM II with a 20 to 25 per cent lower proportion of cement clinker, thus avoiding emissions. What's more, the steel we use consists largely of secondary steel and therefore emits less CO₂  than primary steel.