We have asked Anssi Lassilla, architect, Director and Founder of OOPEAA - Office for Peripheral Architecture - to give us his insights on one of the most sustainable and widely used materials in architecture: wood and CLT.
Here are his answers!
1) Which are the three most important characteristics that could convince architects to use more wood in their projects?
Its sense of warmth and tactility that creates a cozy and relaxed atmosphere.
Its strong sense of identity and character.
Its natural properties that make it an environmentally friendly material for construction when compared to, for example, steel and concrete:
It stores carbon during its entire lifespan.
The air pockets in its cellular structure provide outstanding thermal insulation, which is important specifically in northernmost countries as it makes it possible to have warm, semi-warm and cold spaces next to each other according to need.
Thanks to its hygroscopic properties, wood provides for good indoor air quality and balanced moisture levels.
It ages well and endures well in the climatic conditions of its local context.
It is recyclable and re-usable.
Thanks to its lightness, it is a good alternative for building additional stories on top of existing buildings as a way of making the urban structure more compact.
2) Is it possible today, in a world so refined and technological, to think of wood as the material of the future?
Wood has a very long tradition as a building material. It has proven to have a lot of potential for variations and adaptability; the techniques of building with wood have evolved and have been fine-tuned to respond to the local context and to the needs of people.
An obvious reason because wood should be the material of the future is the concern with ecological sustainability: compared to other common construction materials, wood releases considerably less CO2 per cubic meter of construction material and it continues to store carbon until the wood decomposes and therefore releasing it back into the atmosphere within the natural cycle. Reducing embodied carbon emissions and embodied energy in buildings will be a key strategy in mitigating the environmental impact of the building industry in the future.
3) Thanks to CLT technology, wood is increasingly spreading in the world also as a structural material, and your KOOTA project is an example of this. What are the actual advantages of CLT?
KOOTA is a new wooden housing block to be built in the West Bank of Porvoo, a small historical city in Finland. It creates a new solution for urban living in a way that is both ecologically and socially sustainable and promotes a sense of community amongst the residents. All buildings have a CLT-based structure of massive wood composed of prefabricated modules and a wooden façade. The foundations and the basement level are of concrete. All piping for water, air and electricity is integrated in the walls between the hallways (which are constructed on site) and the individual apartment units that come as fully prepared modules from the factory. This makes it possible to keep the CLT-modules clean during the construction phase as well as to update, change and repair the system without any need to gain access into the apartments.
4) How, in your opinion, will CLT construction evolve?
Wood easily lends itself to modularity. The modules made of CLT can be taken apart and reassembled again offering the possibility of reuse for a different function or another site. CLT modular solutions provide an excellent basis for building collective housing, are efficient in terms of the construction process, and have great potential for further development and variability in apartment types.
5) Wood, not only as building material but also as an urban landmark, as highlighted in your proposal for Allas Sea Pool. Could you elaborate more on this?
The global concept for the Allas Sea Pool Family created by OOPEAA for the company Nordic Urban brings together the Nordic sensibility for the contemplation on nature, particularly the element of water, with a healthy orientation towards physical activity and an urban inclination towards the social aspects of life. The concept envisages wooden floating platforms to be built on coastal sites where it is not possible to build on land, providing spaces for cultural/sports activities and social gatherings. Wood lends itself well for these floating buildings as it is lightweight, and the CLT elements used for the structure are an ecological choice that allows for flexibility in application as well as for sustainability in the life cycle of the building. Furthermore, the transportation of the modular elements is possible to arrange over waterways. The concept builds on the seamless choreography of movement and transition between the spaces and the vistas around, inserting pathways that connect the different types of spaces.
6) What does “sustainability” mean, exactly, when referring to wood’s entire lifespan?
I believe that sustainability must be approached holistically as a social, cultural, ecological as well as economical phenomenon; the most important goal is to strive towards finding solutions that will provide a good quality of life for the users and that take advantage of the natural qualities of the chosen material. From our earliest projects on, I have been interested in exploring optimal solutions that support both the social and ecological aspects of sustainability while simultaneously being economically efficient in a long-term perspective.
That said, regarding wood’s sustainability throughout its entire lifespan, it is important to pay attention to the practices of responsible forestry and to take care of the continuous regrowth of the forests. Wood is at its most sustainable when it is locally sourced, as it also means shorter transportation distances which, in turn, positively impacts ecological sustainability. It provides work for the local labor force and supports the local economy, which contribute to sustainability from an economical point of view. In addition to the sustainable characteristics mentioned before, wooden building parts can be easily re-purposed, moved to a different location or set up in a different configuration, giving them new life.
7) How are you, at OOPEAA, helping in terms of ways to optimize the use of materials?
In recent years, the interest in finding ways to evaluate the impact of materials and create architectonically and technically sustainable solutions has led to our involvement in research projects with a focus on sustainability. Most recently, we have conducted a research and development project for creating an evaluation tool to assess the impact of the material and structural choices on the ecological sustainability of a building project. We wanted to create a tool that could be used already in the early stages of concept design to which we have given the name JOKOTAI Material Impact Screener. The current version is only the very first iteration phase, where it is possible to analyze the impact of alternative material choices in the case of singular buildings. We decided to focus on the most resource-intensive part of a building’s life cycle: the extraction of raw material and the production of the building materials used. It is our intention to continue to develop the tool further and to extend its analysis to address the full scope of a building’s lifespan. JOKOTAI is intended to provide a compass for direction, not a roadmap with specific instructions.
Anssi Lassilla, architect, Director and Founder of OOPEAA - Office for Peripheral Architecture