The Elements of Sustainable Design and Construction; Cindy Harris of the Design Commission for Wales Says the Early Stages of Development Are Vital for Low Carbon Buildings
Byline: Cindy Harris
Design and construction are essential parts of the same exercise - to create a building or streetscape or townscape. While different professions each have their own part to play, the best projects result from both partners working together from an early stage.
This is especially true when it comes to sustainable construction - measures which are necessary to ensure energy efficient, low carbon buildings need to be taken at the earliest possible stage of the design process for maximum impact and practical cost effectiveness.
Aspects of construction and 'buildability' will also affect the design development and the particular materials and technologies specified.
These early decisions will drive key aspects of the project and maximise the best sustainable solutions.
More than half the UK's carbon emissions are generated by the construction and servicing of buildings, so the energy performance of new and existing buildings is crucial to meeting our national commitments and international obligations.
Energy efficient homes offer greater levels of comfort for the occupier and will be cheaper to run and maintain. The social importance of reducing fuel poverty, together with the need to protect the security of fuel supply in the future and to limit the impact of climate change, all combine to deliver a powerful argument in favour of reducing energy use in buildings.
This in turn has a direct effect on bringing down carbon emissions.
At the level of the individual building, the designer, contractor and specialist consultants all need to join forces along with the client to deliver low carbon buildings.
All new housing in Wales now has to achieve Level 3 of the Code for Sustainable Homes as a minimum, together with a 31% reduction in CO[sup.2] levels compared with 2006. The means of achieving this should be set out in the Design and Access Statements accompanying new planning applications.
Used properly they are a powerful tool and should not be reduced to a tick box exercise. Designers and developers should observe the energy hierarchy, whereby the easiest and most cost-effective carbon savings are made first, usually built into the fabric of the building.
These measures are often very simple and cost little to achieve if considered early. They include high levels of insulation to stop heat escaping in the winter and to keep buildings cool in the summer. Equally important is the elimination of uncontrolled draughts, together with controlled ventilation directed when and where it is needed.
The orientation of the building on the site, and the size and location of windows and other glazed areas should be arranged to take full advantage of day light and of the sun's energy - which is both free and renewable.
A passive solar approach to building design uses solar energy to pre-heat the building elements and incoming air, as well as introducing high levels of daylight into the building and reducing use of electric lights.
Once these basic steps have been incorporated, consideration can be given to appropriate renewable technologies which work well at the level of a single building, such as solar water heating, which should meet at least 50% of domestic hot water demand over the course of a year.
The choice of building materials also has a significant environmental impact. Ideally we should be choosing renewable materials that are sustainably produced and locally sourced, with minimal processing and transportation.
Low embodied energy materials are preferred - this refers to the energy consumed (and CO[sup.2] emitted) during the production process and throughout the building's life.
Increasingly we are seeing the use of ultralow-impact building materials, such as timber poles, straw bales, unfired clay bricks, hemp and lime, to construct mainstream, modern, comfortable and energy-efficient houses that have a low embodied energy. …