Ageing is defined by physicists as entropy. The second law of thermodynamics, in simple terms, dictates that all things move from order to lesser order. This is moving from low entropy to high entropy. In principle, without any external influence, any system, material or physical relationship will break down and, if given long enough, will revert back to the atomic building blocks that created it in the early days of the universe. On an astrophysics level, there is considerable debate as to how far this process could go and the potential effect on the universe as we know it. That is many billions of years into the future, a long way removed from the practical considerations of life as we know it. However, what we experience and attempt to control is governed by this principle. On a more mundane level, the pursuit of whole life values and processes has to

accept that entropy, like other fundamental laws of physics, cannot be stopped. Instead, we need to work with it to ensure the principles and procedures we put in place are harmonious with natural laws. This will result in a more efficient and satisfactory outcome in all respects. This is a long way from considerations of whole life value, but it is important to

understand that we are attempting to control and, in some cases, arrest the effects of this principle. We cannot arrest entropy any more than we can stop time. It is always best to start with the basics. With that understanding, we can then

derive means to predict, and perhaps control, the change in any system. The manner in which entropy changes gives rise to the concept of the ‘arrow of time’: a clear indication that time is a universal effect and has a similar effect on all things as far as we currently understand it (although there is still a long way to go in our comprehension of these fundamental issues). Practical construction, use and maintenance processes are forced to accept that very

little can be done to arrest the underlying ageing process. This overriding principle means that, when considering carbon, we are always going to be faced with materials breaking down, and with complex molecular bonds separating and reforming with simpler ones, affecting many materials used across the built environment. This is seen in the ageing process – the breakdown of components, the fading of paints, the discoloration of plastics, etc. The carbon problem emphasises the need for us to understand these processes clearly.

The central question concerning ageing is our ability to predict these processes and to make due allowance for them.