Wooden multi-story construction is gaining more and more interest in the world. Dr Silja Siitonen spoke at the 7th China Wooden Construction Conference, organized by the China Wood Construction Alliance in Yingkou, Liao Ning Province. She described the benefits of wood as a renewable raw material; with not only economic and environmental, but also health and social benefits, promoting further the megatrend of wooden multi-story construction increase in Finland and in Europe.
Wooden Multi-story Construction is Growing in Finland
In Finland, regulation on wooden multi-story construction has been relaxed during the past decades. Earlier, fire safety requirements restricted the construction of wooden multi-story buildings. Despite of the new regulation, the number of Wooden Multi-story Construction projects has remained rather small.
The European Bioeconomy Strategy was formulated in 2012, and partly based on that, also Finland designed its own strategy in 2014. The objective of the strategy is to reduce Finland’s carbon footprint and to prevent biodiversity loss. In addition, the Finnish Wood Building Programme is aimed at increasing the use of wood in urban development, public buildings as well as large constructions such as bridges and halls.
One of the key focus areas of the new Government of Finland is the promotion of wooden construction in Finland. Also, cities and municipalities have lately zoned building lots and entire neighbourhoods only for wooden buildings. It is widely recognized that wooden buildings are important carbon sinks.
Social and Health Benefits of Using Wood
Wooden Multi-story Construction is considered as sustainable housing that provides good living for urban residents. Wood is a renewable, ecological building raw material. The architectural image of wood is appealing: The acoustic features of wood are well-known and therefore it is often used in the construction of concert halls and musical instruments. Also the ‘feel’ of wood is warmer and more soothing than the feel of concrete due to low thermal conductivity. The ambience of wooden construction is experienced as very positive. Fatigue is felt less in wooden rooms, and the colour, the natural smell, and light are experienced as cosy, warm and soothing. According to the Wood for Good campaign, workers in offices with wooden interiors have reported increased feelings of innovation, energy and comfort. In health care facilities, the presence of natural materials is associated with faster recovery times, lower pain perception and positive dispositions.
Bare wood is nontoxic, and its smooth surface prevents the build-up of particles which can occur on other surfaces and finishes; therefore wood is hypoallergenic. Pine and spruce – have antibacterial features due to the various resin acids in the heart of the tree. The use of wood has a positive impact on the air quality in buildings due to wood’s ability to absorb and lose humidity. This decreases the need for air conditioning, improves energy efficiency and reduces the exposure to pollutants. People are known to have experienced positive effects on mood and stress-levels in wooden construction – similar to ones walking in the woods.
Wooden Multi-story Construction is Faster
In general, construction time is shorter in wooden construction than in conventional construction from concrete. This results in smaller financial and labour costs, and earlier accumulation of rental income. Prefabrication of elements shortens construction times and minimizes noise and dust detriment at the construction site. It also shifts work from on-site to factories, and improves work efficiency due to standardized work stages and automation, as well as protects the elements from weather during construction.
Wood is lighter than concrete, which creates savings in transportation, fuel costs and the size of cranes required in the construction sites.
Cost of Wooden Multi-story Construction Still a Factor but Going Down
Currently building with wood is slightly more expensive than building with concrete. However, many of the current wooden construction projects are prototypes or flagship projects, where constructors engage in ambitious architectural design and have intentionally chosen expensive solutions and materials. The main cause for the present higher costs is the limited experience of the constructors. Maintenance costs are estimated to be at the same level in wooden and concrete buildings, so there should be no difference in costs to the end user.
Finally, automation will be beneficial in both planning and the actual construction work. Pre-fabrication allows using automated work in factories and diminishes time spent on-site, decreasing labour costs and shortening the time of exposure to weather. New solutions and new concepts are needed to offer additional value to the customer.
The quality of living and the drive to more sustainable and environmentally friendly solutions will drive the construction industry more towards wooden buildings in the future. Everybody and all industries need to work to combat climate change. Wood construction is one part-solution for that!
The sources of this article include the still non-published Master’s theses of our Junior Analysts Katri Konttinen and Viktor Harvio.
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