What is so special about wood?
Stina Eriksson, an architect at FOJAB, prefers to work with wood. Here she talks about the possibilities of the material and architecture, about climate benefits, new and ancient decay protection techniques and why Germans and Norwegians are better than Swedes at building in wood.
What is so special about wood?
- It has a natural materiality that is easy for us humans to understand. It is alive and beautiful. Wood both absorbs and releases moisture, giving wooden houses a pleasant indoor climate. Solid wood houses also offer wonderful sound environments if you manage to solve the structure-borne noise. Research shows that we feel good about being in a wooden house.
Why don't we build more in wood?
- Until 1994 it was forbidden to build apartment buildings with wooden frames in Sweden, and we are still very much in the old mindset. For many developers, wood construction is unfamiliar territory, especially in Skåne. It requires a different workflow and planning, more logistics that have to work. You have to calculate the construction in a different way and look at the whole picture to make the calculation.
- To create cost-effective wooden buildings of good quality, it is important to work with experienced contractors and designers, and there is a big gap to fill here. Sweden has a large skills gap compared to, for example, Norway, the Baltic States, Austria, Switzerland and Germany, which have been building in wood for a long time. We need more people who know wood and who can share their expertise.
What are the benefits of building in wood?
- In particular, the carbon footprint is lower than for concrete houses. But there are also benefits in terms of faster frame erection, less transportation, simpler foundations and quieter and healthier construction sites. Wood is optimal for building on existing structures, such as adding an extra floor or covering a tramway. There is also no waste in the wood industry - everything is put to use.
What about the disadvantages?
- The challenges are mainly related to fire and acoustics. It is important to involve knowledgeable consultants at an early stage. If you aim to construct a wooden building, you need to design for wood at an early stage in order to get the right governing conditions. It is relatively easy to convert a planned wooden building to concrete, but much more difficult to do the opposite.
- When we look at wood as a facade material, the main considerations are weather resistance, rot protection and maintenance aspects. Moisture is another factor. This is where the aesthetic aspect comes in, where you have to establish early on whether the client is prepared for continuous maintenance through oiling or painting, or whether you should find a product that can age with dignity without significant maintenance.
- There are now many environmentally friendly options for impregnating wood against rot such as heat treatment, treatment with biological fluids from the sugar industry and even pre-pigmentation combined with fire protection. Old traditional techniques are being revived, such as shou sugi ban, also known as yakisugi, where the wood is protected against rot by charring the surface - an ancient Japanese technique that has now become a commercial product.
- There are wood shavings that have been on churches for as long as 600-700 years, so wood as a roofing and façade material should work even today as long as it is treated properly and one is aware of its aesthetic shifts over time.
If we decided to build only in wood in Sweden in the future, would wood be enough?
- It takes just one minute for the Swedish forest to produce the material for an eight-storey wooden house. And for every tree felled, at least two new ones are planted, so both supply and growth are good. In fact, wood production needs to be scaled up in line with the current increase in demand. Waiting times are long today because so much is exported.
- But it is important that we use locally produced wood and that felling is done in a sustainable way. We must protect biodiversity and the forest as a recreational area. Forests are valuable for animals, insects, micro-life, plants and people. It must not just become an industrial resource.
How does wood compare to eco-concrete in terms of climate change?
- A comparison with concrete houses often includes emissions during production and operation, and fails to take into account the energy stored in wood as it grows. So there is a double benefit to building in wood that the concrete industry does not like to talk about when concrete is compared to wood as a material choice. That said, any way forward that reduces carbon dioxide emissions is a good thing!
What trends do you see in the construction of wooden houses?
- A lot is happening and the attention to the Sara Cultural Center in Skellefteå has set Sweden in motion! A lot is about getting the big builders on board. The requirement for climate declarations, environmental certifications and an increased focus on sustainable investments will make it easier to steer towards good climate choices.
- More and more municipalities are also requiring sustainable solutions in land allocations. This may involve scoring developers based on carbon emissions, social sustainability and circular material flows. This paves the way for more reuse, more wood construction and drives innovation and new thinking in sectors and materials that are not currently sustainable.
Does it mean that architecture is changing?
- I hope so! Today, many buildings are quite plain, but I think we will see more ornamentation and carpentry. Wood is an easy material to work with and with robotics and CNC milling there are really no limits to what you can do. The trees are certainly straight, but with glulam and beautiful joining techniques you can create amazing structures and even work with organic shapes.
- But there is still some resistance to wood indoors. In Sweden, there is a style ideal in addition to the practical aspects, which means that architects have to fight hard for clean wooden walls. The modern home should preferably be bright and fresh, and many people find it hard to see past the associations with the 70s ski lodge or sauna when interior wood is mentioned. But perhaps a shift is underway, I sense a change! The best thing is to experience a solid wood house on site - you are surprised by the harmony and the feeling that can be difficult to convince with words.