Anna-Mari Simunaniemi interviewed Markku Karjalainen, Professor of Construction Engineering at the University of Tampere, on topics related to wood construction. Karjalainen believes that the new Building Act, which will come into force next year, alone will increase the use of wood. Among other things, the law obliges developers to take environmental considerations into account as early as the building permit stage.
According to Professor Markku Karjalainen, Finland has the second largest number of apartment buildings in Western Europe. Of the approximately 3,2 million dwellings, 47% are in apartment buildings and about three quarters of new production is still in apartment buildings. Karjalainen points out that building materials have different properties and are better suited to different structures and construction solutions. It is therefore wrong to set materials in competition with each other. For the last 60 years, apartment blocks have been designed and built in concrete. Concrete has a market share of around 98%, so wood is unlikely to take over from concrete for a long time to come.
The environmental emissions of concrete are mainly due to the burning of limestone used in its manufacture. The emissions from this account for about 7% of global greenhouse gas emissions, which is the same as the emissions from aviation. However, Karjalainen gives a pass to the concrete industry, which is constantly developing more environmentally friendly ways of producing concrete. For example, limestone is being burned using renewable energy sources instead of oil and coal, and efforts are being made to develop more environmentally friendly binders.
Karjalainen would like to keep environmental factors and the carbon footprint of buildings at the center of the debate on building materials, as the new Building Act also obliges us to take this into account. He explains the environmental aspects of wood in concrete terms: when a cubic meter of wood grows in a forest, it absorbs a ton of carbon dioxide and releases 700 kilograms of oxygen. In this way, wood acts as a carbon sink, and when used for long-term, sustainable materials, it acts as a carbon store. This is why Karjalainen recommends that wood should be used primarily for long-term purposes, such as as a building material.
Professor Karjalainen gives figures: the amount of wood needed for a summer cottage, or a detached house is around thirty cubic meters. The Finnish forests grow that much in two and a half seconds. The amount of wood needed for a thirty-apartment CLT apartment building with a solid wood frame grows in about one and a half minutes. Finland's forests grow enough per day to cover the annual production of apartment buildings in Finland. This means that construction does not lead to excessive deforestation.
According to Karjalainen, it would make the most sense from an environmental point of view to use locally produced timber as building material. In addition, wood as a building material is important from the point of view of regional security of supply and preparedness, as it is available in almost every region, even in a possible time of crisis.
One of the problems with wood use in Finland, Karjalainen points out, is that people in Finland do not know how to process wood. Better processing could even reduce felling volumes. At present, three quarters of the sawn timber produced in Finland is exported abroad for further processing, which means that its added value is also lost abroad. People often talk about the value of the product and the fact that labor is cheaper in many other countries. Karjalainen does not dispute that labor is cheaper elsewhere. At the same time, he points out that competitiveness consists of much more than the price of a product. Competitive advantages can be the degree of domesticity, ecology, environmental friendliness and localism. Money is important, but there are also other values.
Karjalainen recalls that the promotion of wood construction has been in government programmers since the Lipponen government and is still mentioned in some way. But it is not enough to talk the talk, we need action. Karjalainen says that there has been a lot of discussion about whether wood construction can be encouraged or even forced, for example through zoning. His opinion is that it is possible from an economic and environmental point of view. He argues that municipalities have a multipolar role in zoning, which means that they can determine building materials, including frame structures. However, not all municipalities are willing or able to exercise this right. According to Karjalainen, it may also be because the issue is not seen as important.
According to Karjalainen, almost 99% of summer cottages in Finland are made of wood and around 88% of new detached houses are built with wooden frames. Karjalainen sees the greatest potential for growth in wood construction in apartment blocks, public buildings and halls, where the amount of wood construction could be increased considerably. However, this will also require better wood construction skills on the part of designers.
In timber construction, especially in high-rise timber construction and public spaces and hotels, for example, wood as a building material places certain demands on fire safety. According to Karjalainen, this is not an obstacle to using wood as the main building material. Even buildings of more than eight stores can be constructed using wood, as long as attention is paid to functional fire design. Karjalainen makes a special point that the building material should be considered at the design stage.
Listen to the interview in MY Studio podcast in Finnish here. The podcast was produced by the University of Oulu Kerttu Saalasti Institute's NOHEVA - Low Carbon Crisis Preparedness built on Wood Construction and Tourism.
Author: Laura Veikkola, M.Ed., Project Researcher, micro-entrepreneurship research group MicroENTRE, University of Oulu Kerttu Saalasti Institute
Photo: Ulla Lehtinen
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