Hållbar ombyqqnad

In sustainable construction, it is easy to become interested in all the exciting new build schemes. They look good, they test innovation and they are good publicity. But the biggest environmental, social and economic impacts of the built environment act through the existing stock.

The paragraphs below give a United Kingdom perspective on sustainable refurbishment.

Of the stock that will exist in 2030, 2/3 is already in existence: new build only adds 1-2% to the built stock each year. The rest is likely to have been refurbished - possibly several times - and the nature of these refurbishments is vital for the health and productivity of people who live and work in these buildings, as well as for reducing our environmental impacts.

The challenge for refurbishing and upgrading existing stock is immense - refurbishment projects obviously need to upgrade the structure, the fabric and the buildings services whilst complying with new standards and legislation, but they should also:

Address the potential effects of climate change
Have minimal environmental impact
Conserve our heritage buildings
Provide more safe and secure internal environments
Produce spaces that are adaptable for change of use
Demonstrate best value though procurement and partnering
Contribute to regenerating local communities

Some buildings are cherished, while others are seen as liabilities that are poorly managed until demolition is the only option. This is partly a social and cultural construct. However, in environmental terms, many older buildings (particularly 18th and 19th century buildings) have key characteristics which make them more adaptive and resilient: modest plan depths, high thermal mass, high ceilings and narrow windows. There are lessons to be learnt from the built heritage that has survived thus far. Heritage features are valued by occupiers, but have to be part of a functional whole.

'The dilemma of whether to refurbish or rebuild new is never an easy one, from a sustainability view-point. But generally speaking there will only be a case for partial or complete deconstruction and rebuilding, if the new facility will achieve truly leading-edge performance (i.e. zero carbon like BedZed). Otherwise, and this is currently the more likely scenario, retaining and enhancing existing structures is likely to be preferable, especially when they have innate quality of design or construction. (This is of course a bold oversimplification!)' Dave Hampton, Chairman, CIC Sustainable Development Committee.

Examples:

The National Trust
The National Trust - a UK charity that protects historic buildings - is a well-known example of a property owner that has sought to reduce the environmental impact of its buildings:

The Trust tries to ensure that all materials used in building projects are from as benign a source as possible. The building department holds stocks of reclaimed materials for reuse.
Efficient appliances, energy monitoring and stewardship projects can reduce consumption. For example, approximately 13,000 low energy light bulbs have been installed at Trust properties as an energy saving measure.
National Trust members challenged the Trust at the 1995 AGM to reduce car borne visits from a level of 90% to 60% by 2020. In order to achieve this, the Trust is working on a number of initiatives: better access by public transport; improved facilities for cyclists; and a review of car park provision.
Reducing water consumption and protecting supplies, for example by using spray & auto off taps, waterless urinals, dry compost toilets, cistern and flow restrictors (for staff and visitor facilities).

Sainsbury's
Sainsbury's, a UK supermarket chain, annual energy costs are £50M per year. They aim to reduce carbon dioxide emissions by 10% from 97-98 baseline by 2005. Reducing costs is a driver, as well as anticipating legislation, improving corporate responsibility, and improving comfort. A wide-ranging refit programme involves stepping down voltage supply (reducing energy use by 3%), modifying lighting and control (a reduction of 5%), and recommissioning, optimising and monitoring refrigeration units (a reduction of 10%).

Gårdstensbostäder
In the housing area of Gårdsten, the public housing company Gårdstensbostäder has renovated four residential buildings with a focus on energy efficiency, the integration of renewable energy, sustainable design and improved quality of life. The renovation was planned and performed in close co-operation with the tenants.

Prefabricated roof modules of flat plate solar collectors have been installed on the south-facing part of the new roofs of the seven-storey blocks. The modules function structurally as both solar collector and roof.
Existing flat roofs on the three-storey blocks were rebuilt as mono-pitched north-facing structures, allowing the fixing of wall-mounted prefabricated solar collectors to the south, as well as extra roof insulation
An innovative air heated solar system has been applied to one of the three-storey buildings
Heat recovery systems have been installed on the roofs of the three-storey buildings
Communal greenhouses have been equipped with climate controlled shading devices to avoid overheating.
Existing damaged windows were replaced by new windows with argon filled low energy glazing to improve energy efficiency.

Joint UK-Sweden Initiative on Sustainable Construction

Hållbar ombyqqnad