The construction industry is experiencing winds of change – winds of climate change. As bitingly cold winter temperatures are replaced by mild and humid weather, construction sites must learn to adapt to new conditions.
Overcast summers, rainy autumns, and mild and humid winters. That does not sound like typical Finnish weather – yet. But due to climate change, we must also get used to this kind of weather.
New weather conditions pose challenges for construction. We are already in a situation where, instead of dry and freezing winters, construction takes place in weather conditions that are more humid than what we are used to.
How can we build successfully in the midst of climate change? Do Finns already know how to build in a way that takes into account the challenges brought by climate change?
Juha Vinha, a professor of building physics at the Tampere University of Technology, says that even though research has been conducted on the effects of climate change on construction, it takes a long time for the information to reach construction sites.
The construction industry has been discussing how to take into account the current level of humidity stress for decades, but things have been put into practice at a rather slow rate. Vinha believes that the way the increase in humidity stress is discussed will remain unchanged.
“Currently, much attention is paid to energy efficiency, even though moisture-safe construction would be a much more important topic from the perspective of climate change and construction. Now, as we are seeing an increase in humid weather, it would be a good time for the whole construction industry to start discussing humidity-related problems,” says Vinha.
Waterproofing ever more important
According to Vinha, several climate change-related factors will pose challenges to construction in the future. Increasing rainfall will increase the humidity stress affecting structures, and increasingly overcast weather means that structures will take a longer time to dry completely. Warmer temperatures in the autumn and winter will, on the other hand, increase mould growth.
In addition, temperatures fluctuating close to 0°C cause the water to come down as either snow or rain, causing it to pile up on any parts that project from the building. This causes the snow and its potential freezing to be more likely to form pools of water from which moisture can absorb into the structure.
Waterproofing, a fundamental of construction, will become extremely important in the future.
“We must protect both the structures and the construction materials. Insulation materials must be carefully covered, and if they do end up getting wet, they must be replaced with new ones. This must be done.”
Structures must also be protected correctly. Insulated plasterboard, the structural type currently widely in use, causes a situation where thermal insulation materials and mineral wools placed outside the load-bearing frame are often exposed to moisture for a long time. The structure is made particularly challenging by the fact that rainwater can find its way behind the plaster through various cracks, and once it does, it will take a long time for it to dry. According to Vinha, a structure like this will become ever more susceptible to water damage in the future.
“A thin layer of plaster instead of proper cladding is a risky solution in this changing climate. Problems caused by humidity have already been detected in these kinds of structures, particularly in buildings close to the sea.”
In the future, wood construction will also face growing risks. The increase in the risk of water damage in wood construction is caused by increased thermal insulation, which cools down the external parts of the structure. Therefore, sufficiently warm and dry conditions must be ensured for load-bearing wooden structures, which are easily damaged.
Vinha calls for an especially careful approach in wood construction.
“In the future, wooden frame structures, for example, should use wind barriers offering thermal insulation in the outer walls and underlayment offering thermal insulation on top of the roof truss. This method is already used in Southern Sweden, where the current climate is similar to what we will face in the future. Overall, wood construction requires changes to the structures used, as well as a careful approach and knowledge of the effects of climate change.”
Customer, remember your responsibility
Who is responsible if the construction site falls behind schedule due to not having made the right kind of preparations?
According to Vinha, the customer should assume responsibility for the project. Those starting a construction project should specify the quality requirements and criteria for the implementation of the project.
If the customer is unsure what kind of criteria they should select, Vinha recommends using the Kuivaketju10 procedure, which helps set the right kind of criteria.
Climate change will force us to make changes to the construction methods that we have grown used to. Vinha’s tips for making preparations are simple: we must improve moisture management during the construction process, and structures must be made more resistant to moisture.
“And when the building is completed, you must take care of it and maintain it. That is the only way the building will withstand the changing climatic conditions of the future.”