NCC developed the former KY Building in the Kamppi area of Helsinki into an office building with modern spaces. The carbon footprint of the current property called Kulma21 was calculated based on realised data and compared to that of a similar new building which could have been constructed in the same site. As a result, some interesting data were acquired as to whether or not the existing building was worth demolishing or renovating.
The extensive renovation project of Kulma21 was subjected to carbon footprinting based on completed works of which the result was compared to the construction of a new office building that would likewise fulfil regulations and have similar exterior architecture and scope to those of the renovated building. The calculation was made also considering the impact of demolition works which would have been necessary to clear the site from under a new building.
The result of the calculations confirmed that the short-term emissions (1 – 5 years) from the renovated Kulma21 building accounted for approximately 40% of those which would have been caused by a new building. At a 50 years’ period of review of the life-cycle emissions, the cumulative carbon footprint of Kulma21 is 15% less than that which would have been caused by a new building. The emission impacts of the actual renovation are approximately 44% lower than those caused by the construction of a new building.
It is worth noticing that the carbon footprint calculated for a building’s full life cycle depends largely on the production phase emissions (year 0) and energy efficiency, of which the impact decreases with years of operation. The demolition of an existing building increases the reference carbon footprint of a new building project in the beginning of its life cycle.
– The carbon footprint of a new building cannot be compensated even at a 50 years’ period of review, even if the new building consumed less energy than the renovated one. This fact bears relevance when we ponder over the optimal solution for existing properties situated in an already built environment, such as the central business district. In addition, Kulma21 is a great example of how a ran-down building with a high vacancy rate can be turned into a marketable property. The use of a building can often be brought into conformity with current demands which is true even for properties that are considered problematic. However, this will require multifaceted competence and a more flexible town-planning approach which we, hopefully, will be able to achieve at least in Helsinki in the future, says Head of Renovations Jarkko Heinonen from NCC.