If we are going to build, then it has to be done sustainably; there is no alternative. We do not believe contemporary architecture is truly sustainable at present; many modern buildings have been designed to minimise their environmental impact, but, with their complex technologies, they often do not perform as well as their historic counterparts. Low-energy technologies are expensive, complicated and demanding to maintain, and have an unknown lifespan. Designers like gadgets but users find them perplexing, and if they go even slightly wrong their benefit can be entirely lost. Complexity is the enemy of longevity, and so too of sustainability, so simple passive solutions will last the longest and need to be a fundamental ingredient of how we should be designing long-life buildings.
Giving priority to the effects of human behaviour on nature, to conserving natural resources and planning for the long term is as old as civilisation. It only appears to be new because in the twentieth century it seemed as if science and technology had freed us from many of the limitations arising from our natural context. Not much more than a century ago we had no electricity, central heating or air-conditioning, no cars or aeroplanes. Our enthusiasm for the freedom we have been given by the products of industrialisation seems to have blinded us to their long-term effects, leading us to behave as if the resources of raw materials, energy, food and water available to us were limitless. In designing our buildings and settlements now, we need to understand what has gone wrong with our approach over the last hundred years or so, and how to put it right, combining new ideas with the experience of our predecessors.
Perhaps the most significant bad planning habit of the twentieth century was the fashion, made possible by much better transport, for low density planning and segregation of uses, which came as a reaction against the poor living conditions in the nineteenth century industrial towns. The results of this fashion have been devastating: in the new suburbs, people have to use their cars for almost every activity; community life has been undermined; and huge quantities of agricultural land have been wasted. So it is now urgent to reverse the process, returning to the traditions of dense urban settlements that mix uses together. These traditions not only make it possible for people to get from home to work, school, shops, etc. on foot or cycle, but also encourage personal contacts and therefore social cohesion. And because the buildings are planned very compactly, they shelter each other from the wind, and lessen the heat loss resulting from the high surface areas of detached and semi-detached buildings.
Dense, mixed-use settlement:- POUNDBURY PHASE ONE, Duchy of Cornwall.
Masterplan Leon Krier. Coordinating architect: Peterjohn Smyth
Recent buildings often turn out to be surprisingly shortlived, while their older neighbours continue. The reasons are sometimes poor construction, sometimes insufficiently flexible building form, sometimes inadequate floor heights. We must revive the "long life, low energy, loose fit" approach pioneered in the 1970's. Here again we can learn from dense traditional settlements where the buildings were usually robust and unspecific enough to last for very long periods and to be adapted to different uses over their lifetimes.
Another bad habit of the last century was the tendency to design certain types of building, typically offices and shops in deep plan forms, which rely on artificial lighting and ventilation. Clearly, we need to return to designs that limit buildings depths sufficiently to allow natural light and air to penetrate them effectively. Window proportions are particularly critical in this respect. In contrast to the wide, shallow glazing common in modern commercial buildings, the tall, narrow shape of a typical traditional window throws light and air deep into a room while keeping the glazed area and therefore both heat loss and heat gain to a minimum.
We can do much by wearing warmer clothes in winter and using our opening windows, lights, and central heating systems more economically, but airtight buildings with much better thermal insulation are clearly vital. The German 'Passivhaus' system and 'The Prince's Natural House' are useful models in this respect. Another important factor that is often forgotten is the thermal mass of the building fabric which, if sufficient, will even out temperatures between day and night, summer and winter. It is easier to achieve high insulation standards with lightweight construction but if the forecast increase in global temperatures takes place, northern Europe may well acquire a Mediterranean climate in which heavy construction with high thermal mass is essential to achieve reasonably cool summer temperatures.
This is another area in which modern building is often less sustainable than its predecessors. Materials like steel, aluminium, cement and plastic use a great deal of energy in both their manufacture and their transport over long distances from factory to site. Stone, brick, clay tiles, lime and wood in contrast can be produced relatively locally in an energy efficient way. Embodied energy is also saved by using second-hand materials, which often have the bonus of a particularly attractive appearance.
Second hand clay tiles were used to roof our houses in Luccombe which won the national Design in the Countryside Award in 1992.
If the patterns of new settlements and buildings are based on the principles outlined above they will be fundamentally sustainable and as such will provide a suitable context for the provision of energy sources which are either renewable or make no more than modest demands on our scarce resources. The technology involved in many renewable sources is relatively new, so deciding on which to adopt is not usually simple. Probably the main criteria must be effectiveness, payback period and scale. For example, their payback period currently makes solar panels providing water heating more viable than photovoltaic arrays, while large wind turbines out at sea make much more sense than small ones in sheltered urban settings. It is also important to take wider implications into account. The use of biomass systems on a large scale, for instance, may well make unacceptable demands on land, which would otherwise be available for food production, and it may well not be possible to guarantee future supplies. Ground and air source heat pumps, which are extensively used in Sweden, seem one of the best small-scale systems.
Rainwater is usually so plentiful in the UK that its conservation may not seem important, but in reality there are often shortages, and densely populated and drier areas like London and the South-East, need to supplement their supplies from other areas. So we need to conserve it where we can. The commoner systems include rainwater butts for storage of water for gardening purposes, aerated action water-saving taps, low water use white goods and low-capacity dual-flush WCs, which all simply reduce unnecessary waste of water. Methods that are more ambitious are rainwater harvesting and grey water recycling, both of which need extra care if they are to work effectively. The piped drainage systems introduced in the nineteenth century had enormous public health benefits, but the argument for them for the disposal of rainwater (as opposed to foul sewerage) is less obvious; not only can they cause flooding problems, but they also remove water that would normally percolate into the ground so reducing the natural water table and the level of water in underground aquifers. Where possible we should use permeable surfaces and revive the use of pipeless systems such as soakaways and open channels or swales running along streets and lanes to streams or rivers.
A steep, curving street in our scheme for a site in central Tiverton between the Town Hall and the river Exe.
Not only has modern low-density development gobbled up unnecessarily large areas natural landscape, but also modern roads that are designed with only speed, capacity and safety in mind, often ride roughshod over the countryside, completely destroying its shape and character. Good, dense planning retains much more landscape and ecology automatically, but it should also incorporate streets of shapes and gradients, which respect existing landforms. Limiting the land used for buildings is also essential if we are to conserve an adequate proportion of our existing land used for farming and forestry.
In conclusion, we should draw attention to a key aspect of sustainability that is usually forgotten. If what we build is ugly, people are only too anxious for it to be demolished as soon as possible, whereas if it is beautiful they soon grow to love it, and want to preserve it.
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