(THIS ARTICLE IS MACHINE TRANSLATED by Google from Norwegian)
With the author Daniel Larsen
The field of architecture is faced with a historic problem: How can we design new buildings when we know that the construction industry has become one of the biggest contributors to greenhouse gas emissions? Due to high emissions in the production phase, each "sustainable" new building brings us further and further away from the politically adopted climate targets.
With today's technology for the extraction, processing and transport of building materials, conservation of existing building stock is the most effective measure the construction industry can introduce to reduce its own CO2- emissions. It requires that we have to look carefully and with new glasses at the architecture that ends up under the radar of current conservation practices. This article is a summary of a master's thesis at the School of Architecture and Design in Oslo, where we have investigated the conservation potential of Oslo's non-protected buildings through three different levels of scale – from Oslo via the Bryn neighborhood to a concrete building that is planned to be demolished.
Green list
The problem is eventually known, but deserves a brief summary. The construction industry is responsible for 16 percent of Norwegian greenhouse gas emissions.[1] 70 per cent of these are indirect emissions linked to the production of new buildings, although the supply of new buildings is only 1–2 per cent per year.[2] What is presented in many contexts as sustainable architecture often involves demolishing existing buildings and replacing them with new, high-tech and well-insulated constructions, which will have a low net energy consumption in operation, even if this increases emissions in the short and medium term.[3] Sustainability is no longer sustainable. Every year we demolish 22 buildings in Norway, that is approximately 000 every day.[4]
Buildings that have such good and flexible structures that it would not be prudent to demolish them.
That conservation is an effective climate measure is being articulated by more and more people in the industry. In Oslo, it has been proposed from several quarters to draw up a "green list", as a supplement to the city antiquarian's yellow list of buildings worthy of conservation. This proposal was mentioned, among other things, in the consultation draft for Oslo's cultural environment report 2021–2031.[5] The listing is usually intended as a selective selection of buildings that have such good and flexible structures that it would not be justifiable to demolish them. A problem with this approach may be that it will make it even easier to conclude on demolition if a building is neither included on the yellow nor the green list. If building protection as an environmental measure is really to succeed, it must apply to a large majority, not a limited selection, of existing buildings. In our task, we therefore considered all the buildings that are not protected, i.e. the entire shadow side of the city antiquarian's yellow list.
We mapped this building stock, which makes up 89 percent of the addresses in Oslo, to shed light on the amount of bound energy the buildings possess. The term "bound energy" has been used to describe the amount of non-renewable energy used in the extraction of raw materials, processing, transport to the construction site and construction. Each unlisted address in building
In our mapping, the cadastre has been given a value in kg CO2-
equivalents, which represent expected emissions if the building were to be constructed today with conventional building materials. The map is available on the website www.gronnliste.no. In total, it shows that 13 million tonnes of CO2 is tied up in Oslo's non-protected buildings. That to-
corresponds to the total emissions from Norwegian oil and gas production over the course of one year.
A counter proposal to the ongoing plans for Bryn
Figures from the building register also show that office buildings from 1950–80 in particular are susceptible to demolition. We have therefore chosen to analyze the reuse potential of this building category at neighborhood and building level. Our starting point is the Bryn area, which has been designated as a public transport hub, where 32 existing buildings stand and tremble in anticipation of an urban development that aims for higher land utilization.
The plans for "Nye Bryn", located by the Alnaelva in the east of Oslo, mean that most of the existing buildings will be demolished and replaced with approximately 70 m2 homes and 240 m2 office. To investigate the reuse potential of the existing 150 m2 we have drawn up and analyzed 9 selected buildings that represent the range of building types and construction dates. A common understanding is that physical restrictions prevent the reuse of non-protected buildings. New and stricter regulations are expected to make existing plans, ceiling heights, escape routes and isolation
properties insufficient. We have made a precise drawing of the example buildings in order to find out what these problems may consist of in measurable and comparable sizes.
Based on archival material and our own drawings, we have looked at aspects such as building structure, remaining bearing capacity, the possibility of cutting holes in decks, plan depth, ceiling height as well as the design of rooms, vertical shafts and communication routes. The analyzes show common problems such as a lack of universal design, a poor connection between outside and inside at ground level, and deep plans. Typical qualities that point in the direction of re-use are general and oversized building structures, free plans and facades supported by concrete columns, and many possibilities for fitting in new, vertical communication routes and shafts. Stairs, lifts and escape routes are dimensioned above today's requirements, and so are the ceiling heights if suspended ceilings are removed. Many of the buildings in the category that are often demolished are characterized by similar construction principles, technical details and materials, which can therefore make it possible to work systematically with transformation and building conservation.
Based on the analysis of the existing building stock, we have drawn a schematic counter-proposal to the ongoing plans for Bryn. Primarily through various forms of additions and additions to the existing building mass, we have been able to accommodate 310 m2, which is only 50 m2 less than the current plans. Although the area of the proposal and the counter-proposal are of comparable size, the building protection means a reduction in greenhouse gas emissions of over 55 per cent. The social composition is also affected by the fact that several of today's players in light manufacturing, offices, industry and warehouses are not pushed out of the neighbourhood.
Pragmatic protection
With the project, we have tried to question whether there is a need for an extended range of criteria for valuing buildings. The way antiquarian building conservation has been practiced in Oslo has been called narrative conservation.[6] Instead of the conservation criteria emphasizing urban structure or building types, the purpose has been to care for and retell stories. Although this is no longer a precise description of the city antiquarian's work, building conservation is still concerned with preserving the representative. When excluding approx. 10 buildings in Oslo are implicated at the same time that the remaining 000 per cent have a lower value and can be replaced by new buildings. This logic can be continued through the creation of a selective green list.
A pragmatic protection subject to all built buildings will shift the burden of proof from the city antiquary, who today must argue for the conservation value of their selected building objects, to farm owners, who must be able to prove that the demolition of existing buildings is the right decision also from a climate perspective. This can be done, for example, by requiring a climate statement documenting the environmental impact of demolition, or that the construction is not able to be continued. When conservation becomes the starting point, the protection discussion related to each individual project will be able to become more interesting at the same time and give greater scope for the urban antiquary's professional assessments, and for the architect, who can design additions, additions and changes in dialogue with the existing building.
Our study of the reuse potential of non-protected buildings shows that the building stock is adaptable, and that reuse does not have to come at the expense of architectural quality. In addition to the fact that conservation is the most effective climate measure the construction industry can implement.
[1] Asplan Viak (2019). The construction sector's greenhouse gas emissions. An overview of greenhouse gas emissions that can be attributed to the building, construction and property sector (BAE) in Norway. Report.
https://www.bnl.no/siteassets/dokumenter/rapporter/klimautslipp_bae_2019.pdf
[2] Green Building Alliance (2021). Climate cure for buildings and property. https://byggalliansen.no/kunnskapssenter/publikasjoner/infopakkeklimakjempen/
[3] Fufa, SM, Flyen, C. & Venås, C. (2020). Green is not just a colour: sustainable buildings already exist. SINTEF academic publishing house. sintef.brage.unit.no/sintef-xmlui/bitstream/handle/11250/2719890/SFagprosent2b68.pdf?sequence=2&isAllowed=y
[4] Statistics Norway (2021, 31 March). Waste from construction activity. https://www.ssb.no/avfbygganl
[5] Oslo municipality (2021). Cultural environment report 2021-2031. [Draft hearing.]
https://byantikvaren.files.wordpress.com/2021/05/horingsutkast-kulturmiljomelding-2021-2031-1.pdf-1.
[6] Ellefsen, KO (2008). Narrative protection. Architecture N, 152-59.
