The generally-held assumption is that, by and large, it is quicker, cheaper, and easier to build a new build than to convert an old building. However, the optimum viable use for a local authority-owned building should be the one that results in the most sustainable outcome for the local taxpayer. The ‘Six Ls of Sustainability’ framework can help local authorities take asset management decisions on whether it would be better to adapt a heritage asset to a new use compared with alternative means of accommodating that use such as a new build.

1. Longevity

   A building that achieves a long life amortises the embodied energy and use of resources over the maximum time possible. A heritage asset is typically built to last with many sustainable features that respond to climate and site. The energy embedded in a heritage asset can be 30% of the embedded energy of maintenance and operations for the entire life of the building.

2. Loose-fit

   Given that patterns of occupational requirements can change rapidly, a heritage asset that is readily adaptable for both other users within the same use class category or to an alternative use class, better meets the definition of a sustainable building.

3. Low carbon

   It is self evident given the targets for CO2 reductions and the drive for a low carbon society that a sustainable building is one with a low carbon footprint. It is now well-documented that heritage assets are naturally relatively efficient in energy consumption or can be improved fairly easy. For example, locally sourced and re-usable building materials used in restoring many heritage assets such as lime mortar and lime wash are less energy-hungry than many new construction materials. Similarly, although an original single-glazed window may have an efficiency rating considerably poorer than modern standards, thick masonry external walls are likely to give the building much better thermal performance overall than the Building Regulations require. At times however actions to reduce carbon emissions may present conflicts such as the insensitive alteration of heritage assets.

4. Locationally appropriate

   The location of a heritage asset will impact on its economic value; it will also affect the environmental impact of the building. One that can only be reached by car will not only increase the environmental impact but, if restrictions on fuel are introduced or fuel costs rise, such buildings may depreciate in value disproportionately. However, a building that is inaccessible by car may, depending on its use, simply not meet occupational needs.

5. Liked by occupiers

   Research has shown that occupiers of well-designed, mixed-use developments particularly benefit from the better performance, loyalty, health and satisfaction of their employees and from the increased prestige that such developments command with visitors and clients. Re-using heritage assets within a mixed-use development can be a highly effective catalyst for regeneration. Their restoration and adaptation to a mix of residential and other uses encourages spatial interaction both within the building and at street level. The existence of a readymade context allows the new uses to bed in more satisfactorily than is usually possible with new build schemes.

6. Lovability

   Buildings have stakeholders who are ‘internal’, i.e. who have a direct interest (legal, financial or employee). They also have ‘external’ visitors. Many historic council buildings embody the collective memory of communities and enhance the quality of people’s lives. Research suggests that buildings which have the ability to inspire a positive response among external stakeholders as well as those with a direct interest will be more likely to achieve longevity.

Source: Sayce, Walker and McIntosh, Building Sustainability in the Balance, London Estates Gazette, 2004