Principal Issues to Consider in Sustainable Construction
Consider the Location and Siting
Can the building be orientated to make the most of heat gain in winter, yet be well shaded in summer? Will it be well placed to make use of renewable energy? Is it in a location that gives access by public transport, cycling, walking? Is it in an area that is likely to be at greater risk of flooding with global warming?
Adaptation to Climate Change
The forecasts of global warming show that there is likely to be a greater incidence of storms and therefore an increased likelihood of flooding events. Locating outside of possible flood plains is only an option for some businesses and others may need to adopt more local methods to prevent inundation. In addition, in higher risk areas, there are construction methods that allow the swifter recovery of the building, such as the appropriate use of materials and moving electricity supply and other essential services away from lower levels. At the other extreme, higher peak summer temperatures are anticipated. Construction techniques such as the use of “brise-soleils” to shade windows can reduce heat gain, while the effective use of landscaping to provide some shelter to buildings and green open space to act as a heat sink can help to minimise the over-heating impact.
Use of Sustainable and Recycled Materials
A wide variety of products are available now that either make use of recycled materials or come from sustainable sources. Timber should be sourced from sustainable supplies and there are a number of registration schemes that guarantee such products. Peat-free compost for landscaping will protect the dwindling areas of ecologically rich peat bogland. Materials for insulation can include recycled paper, while hemp-based building blocks can provide a thermally efficient wall.
Environmental Protection and Enhancement
The impact that a new building has on its immediate environment will be a matter that will be considered by the local district or borough council when dealing with a planning application. Sensitive design and location can often avoid or reduce damage to the environment, for instance in terms of the impact on bio-diversity or on light pollution. Furthermore a carefully designed project could actually mitigate any damage or even enhance the bio-diversity on the site. There are opportunities to make use of effective management of any open spaces, landscaped areas, run-off ponds or green roofs on the site to achieve these objectives.
Energy Efficiency of the Building
At the very minimum, the insulation qualities of the building will need to meet the Building Regulation standards. But careful consideration of the nature and design of the building in the first instance can make a radical difference to its likely energy consumption. For instance a building that needs to be cooled by air conditioning will generally have a much higher energy consumption, and therefore running costs, than one that does not. New techniques of construction that make use of the mass of the building for cooling as an alternative to air conditioning are now being more widely used. New materials can also provide greater energy efficiency, for instance hemp blocks for walls, sedum or grass roofs and higher standard glazing options. Examples of all of these approaches can increasingly be seen around Suffolk.
More Efficient Energy Sources
There are a wide variety of opportunities to use renewable energy sources in new buildings. Solar panels can provide hot water and photovoltaic cells will generate electricity. In the right locations, wind turbines can also contribute to the electricity needs of the business, and ground or air source heat pumps will provide economic heating facilities. Boilers using non-renewable fuels such as oil and gas can be replaced by bio-mass boilers and there is a particular trend in Suffolk for using wood fuel in the form of pellets or chips sourced from local woodlands. Even if renewable sources are not suitable for particular locations, more efficient use can be made of traditional energy sources through means such as combined heat and power (CHP) or local wire systems for distributed energy generation. These different options for the use of energy will need to be influenced by the location, size and characteristics of buildings and the way in which they are likely to be used. Specialist advice will be required for individual circumstances.
Considerable opportunities exist to recycle the waste produced on a day-to-day basis in building. However, space is needed to allow this to take place. Appropriate storage is needed within and outside the building to allow waste to be sorted into different streams. This should be provided for in the design of new buildings.
Suffolk lies in one of the driest parts of the UK and increased population and water use per capita is already placing pressure on our water supplies. Furthermore hotter, drier summers that appear likely to be a consequence of global warming, will place an even greater strain on these resources. One solution is to pump water from other wetter parts of Britain, but this causes local environmental damage, adds to the costs that will be passed on to the consumer, and will increase energy use in pumping the large volumes of water across considerable distances. Another alternative of desalination plants around our coast is likely to be even more costly in energy terms. Therefore the more efficient use of water in new buildings can reduce costs and benefit the environment. Ways in which this might be achieved are through fittings which minimise the use of water in, for instance, washing facilities and toilets. “Grey water” systems and rain-water harvesting can provide water for uses such as flushing toilets. By the nature of a lot of the options available, they are far easier to install during the construction of a building than in the retro-fitting them to an existing building. A further issue to consider is what happens to the run-off from the building and its surrounding site, including the access roads and car parks. The installation of “sustainable urban drainage systems” (SUDS) can reduce the likelihood of local flooding and assist in the re-charge of the water table from which much of our supply is drawn.
In a construction project, unless the site is on a greenfield, there are often materials in existing buildings that can be re-used as hard core or fill in new buildings. In addition across the UK, some 13 million tonnes of products are delivered to sites every year and not used. Overall, construction accounts for one third of the nation’s waste material. Better practice in re-using materials and in managing site waste can reduce build costs by 3% on average.