Sustainability and Conservation of the Historic Built Environment - an IHBC Position Statement

PS2020/1, April 2020

The Institute of Historic Building Conservation (IHBC) recognises that climate change is a fundamental global threat that demands appropriate responses from all who have the ability to influence change. The IHBC believes that conservation of the historic built environment is an essential component of the response to the threat posed by climate change and long-term planning for sustainable development. The following key points underpin this belief:

1. Conservation of the historic built environment is an inherently sustainable activity. It involves caring for places, both urban and rural. Fundamental activities include re-using historic buildings and re-shaping historic areas to facilitate their long-term use. The historic built environment is a non-renewable resource and securing its long-term survival is an essential component of sustainable development.

2. Historic buildings contain large amounts of embodied energy and carbon. Further energy and carbon release is required to destroy them and construct replacements, therefore re-use of both buildings and places is desirable in principle. This does not mean that all old buildings and areas have to be kept. Judgements on retention need to balance architectural and historic significance against any wider benefits that might arise from replacement and redevelopment.

3. Most historic buildings are old, and the majority have outlived the design life of modern buildings. The longer buildings can survive, the greater the contribution of their embodied energy to sustainability. Traditional building materials such as brick and stone tend to be very durable and their appearance often improves with age. Modern materials tend to be less durable and their appearance often degrades with age.

4. Historic building conservation practice emphasises the importance of maintenance and repair, which is fundamental to longevity. Poor maintenance not only hastens the demise of buildings, it also makes them less comfortable and causes users to consume more energy, for example to combat draughty windows and walls made damp by blocked gutters or leaking roofs. Repair is a fundamental consideration in improving energy efficiency.

5. Historic towns were often a model of sustainability. Most were large enough to sustain an urban population but small enough to enable inhabitants to move around them without modes of private transport that harmed the town. Many people lived in close proximity to places of employment. Longer journeys generally utilised public forms of transport. As historic areas were often designed for walking, they tend to be very permeable and legible. Sensitive management of change in historic towns and areas, that conserves and enhances their key architectural, townscape and historic characteristics, sustains and improves the quality of life for both inhabitants and visitors. Quality of life is a key component of sustainability.

6. In the UK, the planning system has a responsibility for quality of life and has historically supported the preservation and enhancement of amenity. More often than not, historic towns, villages and designed landscapes are attractive and characterful places that provide high levels of amenity and add much to the quality of life and well-being.

7. There is much to learn from historic towns in terms of such matters as mixed-use, scale, layout, density, orientation, variety, and historic townscape. Historic centres tend to be well served by public transport and provide concentrations of local facilities. Most historic places developed incrementally, which generally resulted in a fine grain of mixed uses and more sustainable live-work patterns than in modern planned towns. Designing and adapting places to accommodate and prioritise large-scale use of the car invariably degrades the character and quality of historic towns.

8. Similarly, much can be learned from historic man-adapted and designed landscapes, which invariably support bio-diversity and contribute to flood alleviation. The designed landscapes of country houses, many of which are accessible to the public, and historic public parks that were established in the nineteenth and early twentieth centuries are now almost always seen as invaluable local resources that support mental and physical good health and well-being.

9. Historic buildings and places are not always perfect. Buildings of traditional construction may not naturally perform as well as well-designed modern buildings in terms of such matters as energy efficiency. However, there is often scope to improve their performance, through appropriate repairs and adaptations conceived with sensitivity and understanding. Provided alterations to historic buildings consider the buildings holistically, taking account of functional performance, historic fabric, architectural issues such as character and appearance, and the need to optimise medium to long term performance, they can usually be made more energy efficient. Historic towns may not always meet modern-day needs. However, experience has shown that they can often be adapted with sensitivity, without causing harm to their essential qualities, townscape characteristics, and heritage value.

10.Traditionally constructed historic buildings can be either designated or non-designated. All have the potential to contribute to a sustainable future, provided they are treated with respect. Many will offer scope for adaptation to enhance performance. Where retrofit adaptations would result in a degree of harm to architectural and historic value, a balanced judgement can be taken, taking account of the relative significance of the building and its contribution to environmental quality. As the most significant historic buildings, which need to be treated with the utmost sensitivity, form only a small proportion of the overall building stock, it may be justifiable to retain such buildings in an unaltered state, if proposals to retrofit them would result in serious harm to the architectural and historic value of the building.

11.The designers of new buildings have much to learn from traditional forms of construction and design, for example, in terms of how they cope with moisture and air movement and in building orientation. Adjoining residential properties in low and medium rise traditional terraces and blocks tend to be thermally efficient as they insulate each other. Good conservation practice recognises the inherent differences between traditional and modern forms of construction, which should always be understood when considering retrofit proposals for historic buildings.

12.The great majority of historic buildings were constructed using local materials, with minimum need for transportation. Where heavy materials had to be transported, this was traditionally done by water. Timber components in historic buildings have the capacity to last longer than the time taken to grow replacement trees for the ones felled to make the components, making them carbon neutral. Use of traditional materials, and local materials where possible, minimises carbon footprint and environmental impact.

13.Historically, building materials were highly valued and were re-used wherever possible, enabling them to be used to their maximum life and potential. Lime mortars enabled bricks and stone to be salvaged. Timber-framed buildings could be deconstructed and re-erected elsewhere or the timbers could be re-used. Roof-covering materials were often salvaged for re-use. Modern practices such as use of cement mortars prevents re-use.

14.Traditional craftsmen usually operated locally, providing local employment and operating with a minimal carbon footprint. Skills were passed on from generation to generation, ensuring the survival of sustainable practices. The repair and adaptation of historic buildings offers great opportunities for new and rewarding local skilled jobs.

15.Historic buildings and places cannot always accommodate all forms of renewable energy sources. However, provided the type and location of any renewable energy feature is carefully considered, there is often scope to introduce such measures where they can be installed in a reversible manner and without causing material harm to heritage significance.

16.Supporting skilled and appropriate care, repair, maintenance and suitable adaptation of the historic environment to facilitate long-term use, is a carbon management strategy that brings unique benefits to society.

The Institute intends to promote sustainable practices by:

• Provision of relevant information to members, other professionals, and the general public, through its online ‘Toolbox’ facility, its regular ‘Newsblogs’, its journal ‘Context’, and its Annual School.
• Provision of relevant opportunities for continuing professional development for IHBC members at both branch and national level.
• Encouraging IHBC members to prioritise their knowledge of sustainable practices and to incorporate such knowledge into their practice.
• Working with other organisations, such as The Sustainable Traditional Buildings Alliance, the Climate Heritage Network and Heritage Declares, to promote a sustainable approach to conservation of the historic built environment.

Final version, as approved by trustees at IHBC F&R+ on 2 April 2020. Original source: https://ihbconline.co.uk/toolbox/position_statement/sustainablilityconservation.html

--Institute of Historic Building Conservation

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