Quantification of material stocks in existing buildings using secondary data—A case study for timber in a London Borough

The existing building stock represents a huge accumulation of physical resources: a material ‘reserve’ that could be mined in the future to improve resource efficiency. However, in the absence of systematically collected information about materials deposited in the built environment, the ability to manage and exploit them is limited. An approach to quantification of material stocks based on the use of secondary data from external research bodies, national statistics and a housing stock management database is used to estimate the timber stock in residential buildings constructed in the London Borough of Tower Hamlets before 1992. Results show a total timber accumulation of almost 67,000 tonnes across 68,000 dwellings, with a material intensity for timber between 20−34 kg/m² of building floorspace (6.8–11.2 kg/m³ of gross building volume) for terraced houses and 5.4−11 kg/m² (1.8–3.6 kg/m³) for flats and maisonettes. Generally, there is more timber in floors and roofs, and in older buildings. This method appears to be robust, as it results in comparable timber intensities to those determined using other methods in previous studies. It can be used for other materials and may be useful in other contexts where data is available (i.e., other scales, building types and materials), and capable of contributing to the growing understand of existing buildings as material banks.