Estimating the material stock in wooden residential houses in Finland

The aims of this study were to quantify the amount of wood in residential houses in Finland in 2017 that could be available for cascading, and to characterize the age distribution and gross floor area of the houses in the stock. Through a bottom-up material stock analysis, the mass of wood and the gross floor area of buildings in each building type and construction period were estimated. The study found that 10 million tons of wood are contained in the structures of residential houses built before 1969, equivalent to around 59% of the stock. Since much of this stock is nearing end of life, this material should soon become available for cascading so providing a significant potential resource. It was also found that, overall, the structural parts of residential houses embody 17.5 million tons of wood, of which around 9 million tons is, theoretically, reusable and recyclable. However, for effective reuse and recycling, further analysis of the quality, type and future availability of recovered wood is required. The current results could be used for material stock and flow analyses to help planning for the use of recovered wood. Further research is needed to fill in gaps in the time-series of the number and gross floor area of buildings constructed and their average gross floor area. Moreover, a material intensity analysis of Finnish buildings is needed to better quantify the wood used.