Wood becomes more popular in the construction of apartment buildings – the majority of the environmental impact of buildings is created during use

The construction industry needs to reduce its environmental impact, and public investments in the promotion of wood construction are part of this development. YIT is constantly improving its competence in wood construction. The environmental impact of material selections requires additional investigations, but it is already clear that climate action should also be directed at reducing life cycle emissions.

Wood construction is becoming increasingly popular, and policies concentrating on addressing climate change, both at governmental and municipal levels, are boosting this growth. In September, the Ministry of the Environment released the objective of increasing the market share of wood construction in all new public construction to 31% by 2022 and 45% by 2025. In 2019, the share amounted to 15%.

The decisions are based on the objectives of reducing greenhouse gases: Finland aims to achieve carbon neutrality by 2035 and, potentially, carbon negativity by 2040. This carbon neutrality goal has also been adopted by, for example, the City of Helsinki, which has declared its intent to find all possible solutions for reducing the emissions of buildings and construction.

“The climate objectives cannot be reached unless the construction industry fully commits to climate action,” says YIT’s Head of Sustainability Mia Ranta-aho.

Wood or concrete?

Wood construction is becoming popular as people believe it is one of the most effective means of minimising the emissions caused by buildings. In public discourse, wood and concrete are often pitted against each other, and the carbon storage capacity of wood is a frequently mentioned factor. On the other hand, people have become concerned over whether the increasing use of wood materials will reduce the active carbon sinks of forests.

The differences between the materials have also been studied in recent years. The Re-thinking Urban Housing programme of the City of Helsinki, for example, built two nearly identical residential buildings between 2018 and 2020, one with a concrete frame and the other with a wooden frame. The goal was to compare apartment buildings with a concrete or a wooden frame in both the design and construction stages and during use.

The comparison revealed that the emissions caused exclusively by the construction materials were about 20% lower in the wooden-frame building. However, reviewing the entire service life of the buildings within the scope of 100 years narrowed the gap between the two buildings. In this scenario, the life-cycle emissions of the wooden-frame building amounted to 6% less than those of the concrete-frame building.

“This type of benchmarking is important but needs to be updated as we gain new information on the actual positive and negative climate impact of different materials,” says Director of Environment & Energy Pekka Vuorinen from the Confederation of Finnish Construction Industries RT.

More emphasis on life cycle

What is also noteworthy in the results of the Re-thinking Urban Housing programme is that, in the long-term review, most of the project’s emissions depended on factors other than the choice of frame materials. In-use energy consumption constituted three quarters of all the life-cycle emissions.

The results are in line with the comprehensive calculations prepared for the Low-carbon Construction Industry 2035  roadmap of the Confederation of Finnish Construction Industries RT.

“We prepared the roadmap in cooperation with stakeholders and the Ministry of the Environment as a response to Finland’s carbon neutrality goal. According to the calculations, the in-use energy consumption of buildings makes up 76% of the annual carbon footprint of the entire built-up environment in Finland. Construction materials, such as concrete, steel and wood, constitute half of the remaining quarter of emissions. The share of construction site activities and transportation is slightly smaller. What is important is that all the operators review their emissions and aim to reduce them,” says Vuorinen.

He emphasises that the key decisions concerning the environmental impact of buildings are made in the design and planning stage. It is not always possible to change the decisions made in the design and planning stage during use and, even if it is possible, it may be expensive. Reducing emissions is important, but it must be achieved in a controlled manner without risking the various characteristics of the building’s life-cycle quality.

“The building’s environmental and climate impact must be examined within the scope of its life cycle in the design and planning stage. Improving the technical characteristics of the building may, in some cases, increase the costs and even the emissions created in the construction stage, but the improvements may also significantly reduce the building’s life-cycle energy consumption and environmental impact”, Vuorinen says.

Product development offers support for environmental goals

The life-cycle approach is also highlighted by Juha Kostiainen, Senior Vice President, Sustainable Urban Development at YIT in his blog on the Kivifaktaa website of the Finnish Concrete Industry Association and the Confederation of Finnish Construction Industries RT. 

“Some cities have included the requirement of wood construction in their land allocation terms. It’s a good requirement if the goal is to promote wood construction. If the goal is to promote low emissions, I would advise setting boundary conditions for life-cycle emissions. There are already some decent tools for calculating emissions. If the goal is to promote innovation, it is wiser to specify the goals for the end result instead of dictating the technical solutions,” says Kostiainen.

When hoping to considerably reduce the emissions of construction materials, Kostiainen believes it also requires the development of new solutions. In addition to research institutes, this work is carried out at the development laboratories of wood product and concrete manufacturers.

As an example of the latter, Kostiainen mentions Norway, where operators have been able to produce cement through a bacteria-based process without the environmentally damaging burning of limestone. In Finland, operators have developed geopolymers out of industrial side streams, and some stone-based construction parts reach up to 40% lower emissions in commercial products.

Modules boost the construction of wooden apartment buildings

The trend for the near future is clear: an increasing share of new buildings in Finland will be made of wood. It is important to reduce the emissions of all construction materials through development and better solutions. This is also reflected in the YIT strategy, which includes ambitious goals for reducing emissions.

“We plan to cut the carbon dioxide emissions of our operations and our self-developed projects in half within the next decade. There is no cure-all solution for reaching this goal; it requires, among other things, improving operational efficiency and reducing waste, implementing new circular economy and material solutions and making broader use of renewable energy,” says Mia Ranta-aho.

YIT became a constructor of wooden apartment buildings in early 2020 with the construction of As Oy Tampereen Tohtori in Hervanta, Tampere. For a long time, YIT has used bathroom, slab and wall elements in its production. However, Tohtori is YIT’s first wooden apartment building project built entirely of modules.

“Wood is a heavily discussed topic but, so far, not many operators have built entire wooden apartment buildings. Currently, each new wooden apartment building is a pilot project, which may make the design, planning and construction more expensive than with more familiar materials. The price gap will grow smaller as operators gain experience and establish functional processes,” says Marko Oinas, EVP, Housing Finland and CEE segment at YIT.

The largest assets of wooden module construction include shorter turnaround times. 

“Prefabricated modules may even cut the construction time in half. Other assets of module construction include excellent production conditions and occupational safety. About 80–95% of the building is completed at the factory, with more optimal temperature, humidity, lighting and ergonomic conditions compared to working outdoors on a construction site,” says Oinas.
 

For further information, please contact:
Marko Oinas, Interim Executive Vice President, Housing Finland and CEE segment, YIT Corporation, tel. +358 40 506 7430, marko.oinas@yit.fi 
Johanna Savolainen, Communication Manager, YIT Corporation, tel. +358 44 305 4594, Johanna.savolainen@yit.fi 

YIT is the largest Finnish and a significant North European urban developer and construction company. Our goal is to create more sustainable, functional and attractive cities and living environments. We develop and build apartments, business premises and entire areas. We also specialise in demanding infrastructure construction. We own properties together with our partners, which supports the implementation of our significant development projects. We also provide our customers with services that increase the value of properties. We employ approximately 7,400 professionals in ten countries: Finland, Russia, Sweden, Norway, Estonia, Latvia, Lithuania, the Czech Republic, Slovakia and Poland. Our revenue in 2020 was approximately EUR 3.1 billion. YIT Corporation's share is listed on Nasdaq Helsinki Oy.