Adapting building construction to the effects of climate change

Climatic agents play a prominent role in the deterioration of building fabric, and a change in climate is expected to have a significant effect on deterioration rate. This paper distinguishes between two types of mechanism leading to building failure. In the first, increases in background deterioration occur at the building material level, due to an increase in severity of the agents involved e.g. material degradation by ultra-violet dosage. In the second, an increase in sudden damage from extreme events affects whole building elements or even whole buildings e.g. roof loss from wind gusting. An increase in background deterioration can be offset by more frequent maintenance and by improvements in materials technology and design. In contrast, an increase in extreme climatic events would cause rapid damage requiring replacement of whole building elements, which is more visible and frequently more costly. Building codes set acceptable standards of tolerance to these background and extreme events and will play their part in ensuring a relaxed assimilation of the change if revised appropriately. The relevant codes and standards are based on long term measured data, such as wind and snow load expectations. They need to become flexible enough to account for changing climate within the lifetime of a building, which may be more than 100 years. The shift towards performance standards that refer to a base set of climatic data has made revision easier, as the base sets can be modified in step with climate change without affecting the parent code. Variables available from climate change modelling, however, are not always suitable for modifying this base climatic data, which may refer to event durations (e.g. rain exposure), frequencies (number of days with frost), ranges (diurnal temperature swing), dosages (lux-hours), combinations (driving rain index) or probabilities (e.g. storm risk). The variables that are required are discussed further in this paper.