Report: Learn from the best experiences of using wood in construction
In a major report, BUILD at Aalborg University has examined the climate footprint of 45 visionary wooden buildings, measured across the entire life cycle of the buildings. Construction engineering experiences from 35 projects are also featured in the inspirational directory, which has been created for others looking to use wood in construction.
How can wood help reduce the carbon footprint of a structure, while also contributing to healthy, aesthetically pleasing and durable buildings? The new report from BUILD (Department of Civil Engineering) at Aalborg University sheds new light on this issue.
In the report, researchers from BUILD have collected data and experiences from 41 wooden buildings in Denmark and four in Norway. The purpose is twofold: documenting the carbon footprint of the buildings and communicating experiences from wood construction projects.
The report calculates and presents the climate impact from all of the buildings and also offers an inspiring collection of cases highlighting 35 of the projects. The purpose of the collection is to provide references for others who might be planning to use wood in construction projects.
Seven priority areas
The case collection includes several types of buildings, ranging from residential homes and offices to institutions, schools and cultural sites. These have been categorised based on whether the wooden buildings are box modules, flat-pack elements (including cross-laminated timber - CLT), a light-weight wood structure, glulam structure or a hybrid between several of the four.
The BUILD researchers collected construction engineering experiences from each project through interviews with architects, engineers and builders. These focused in particular on the seven points that are especially important for wooden buildings:
The report also notes that wood should only be used if it adds value to a structure and that the industry must consider the possibilities for reusing wooden products rather than burning them when the products reach the end of their service life. It is also important to select wood from forestry that takes into account both biodiversity and the ongoing ageing of the wood.
Finally, the report notes that the structure's sustainability is not just about wood - flexible buildings and a focus on users, for example, are also important.
From large wooden structures to ready-made modules
Troldtekt acoustic solutions are also part of the design of several of the projects in the case collection.
At 6,500 square metres, Erlev School near Haderslev is one of the largest wooden structures in Denmark in recent times. Emphasis has been placed on individual learning, with flexible learning environments configured using architectural clusters. Troldtekt ceilings solve an acoustic challenge while serving as an air inlet point for fresh air from the concealed ventilation system. Arkitema designed the project, with the engineering firm SlothMøller acting as an indoor climate consultant.
The residential project Lisbjerg Bakke'sthree and four-storey buildings were erected as a construction system made from solid wood and untreated wooden facades. Troldtekt acoustic ceilings have been installed in the communal spaces in the project. Lisbjerg Bakke has won several Danish and international awards – including 'Building of the Year 2018'. Vandkunsten Architects designed the project.
The student halls of residence Studio[Home] are located in Lundtofte near Copenhagen. Vandkunsten Architects also designed this project and each apartment was constructed using wooden room modules. The project was the first construction project in Denmark to achieve sustainability certification under both the Nordic Swan Ecolabel and DGNB Gold standard schemes. Troldtekt acoustic ceilings have been installed in the communal spaces, where many students spend time throughout the day.
Feldballe Independent School
Feldballe Independent School on Djursland has been given an extension that was constructed using local and bio-based materials. The structure is breathable despite the excellent insulating properties and causes no degassing. In addition to great acoustics, the Troldtekt acoustic panels used on the ceiling also create a calm atmosphere in the room. Henning Larsen Architects designed the project.
Vandkunsten designed the 33 homes in Ry, which all consist of different types of semi-detached homes. The retirement housing community also includes a communal building for which Troldtekt products were used in the design.
Carbon footprint over the entire life cycle of the buildings
The report from BUILD shows that 41 of the 45 wooden buildings have a carbon footprint that falls below the limit for newbuilds set out in the Danish Building Regulations (BR18). The limit has been set at 12 kilos of CO2 per square metre per year (kg CO2 eq./sqm/year).
The calculation of the CO2 footprint includes phases from the entire life cycle of the buildings (LCA). This relates specifically to the following phases in an environmental product declaration (EPD):
- Product phase (A1-A3)
- Construction phase (A4-A5)
- Replacement of materials (B4)
- Energy consumption (B6)
- Waste management at the end of service life (C3)
- Disposal at the end of service life (C4)
The actual wood used in the construction materials is carbon-neutral in the calculations. The explanation for this is that wood absorbs CO2 during growth and releases the same amount of CO2 at the end of its life. However, there may be emissions linked to e.g. the production and transport of wood products, but the report shows that the wood-based products used in virtually all of the 45 projects account for a very limited proportion of the total climate impact from materials.