Listed buildings are important architectural testaments to a society's rich and diverse history. Formally recognizing these buildings protects their significant architectural elements from alterations and demolitions while creating socio-economic avenues to aid their conservation. However, these buildings also run at risk of being alienated from new materials and modern building systems that allow them to function optimally today.
Integrating new materials and building services without interfering with the building’s original character is a unique design challenge. Whether adding new materials during structural renovations or integrating modern fire protection systems, there is a need for sensitivity and balance. This applies to various elements of listed buildings, including walls, floors, roofing, and façades, ensuring they are future-proofed for an extended lifespan.
Future-proofing is a sensitive concept in the restoration of listed buildings. It means preparing for changes in a way that protects a building’s historic character while extending its lifespan and conserving resources. Achieving the right balance between protecting the special interest of a listed building and proposing alterations and extensions is tricky. Some buildings can accommodate change better than others. The ability of a building to sustain alteration or extension depends on its type, significance, and the merit of the new work. Some buildings may be sensitive to slight alterations, while others may be less so. This is why future-proofing is complex. However, the underlying principle is that no harm is done to the structure during the intervention that would alter it or make its features unavailable to future generations.
There are multiple principles behind future-proofing listed buildings, and the Secretary of the Interior’s Standards for the Treatment of Historic Places provide excellent guidance for the long-term retention of historic buildings. Firstly, interventions in historic structures should allow people to appreciate both the original building and the updates that have kept it viable. These interventions should also be flexible and adaptable to the environment, uses, occupant needs, and future technologies. When supplementing new materials for older ones, consider durability and redundancy. Materials that deteriorate more quickly than the original fabric would require further interventions, shortening the building's service life. Additionally, interventions should prepare the building for the impacts of climate change by reducing energy consumption and using durable materials to minimize material consumption.
In specific elements, such as walls, alterations to listed wall surfaces must match the existing fabric and materials in composition, quality, color, and texture. However, modern insulation for that wall may become necessary to future-proof the building’s performance. Fitting external insulation may negatively affect the detailing of windows and doors and require changes to drainage and rainwater systems. Internal insulation may alter the historic proportions of a room, obscure plasterwork, and necessitate changes to services, skirting, and architraves. Therefore, the choice becomes sensitive to the listing grade, building type, function, and adjoining building elements.
Another example is listed facades, where carved and other sculptural details, such as molded brickwork, stonework, and terracotta decorations, are an integral part of the design and character of some buildings. Modern alterations to exterior lighting performance need to be designed to match the existing sculptural details while avoiding a major display of electrical service routes. This means that new additions to help future-proof the façade need to be designed sensitively to avoid altering the building's form. Additionally, the Institute of Historic Building Conservation guidance toolbox offers extended procedures for alterations and extensions to all building elements, including roofs, doors, windows, and modern fixtures and fittings. It highlights the integration of modern building requirements such as fire escapes, meter boxes, solar panels, floodlighting, and external flues.
Furthermore, future-proofing involves integrating more services, and there's a much wider range of building services in use today than in the past. These include mechanical, electrical, fire prevention, and plumbing or public health engineering. According to the National Heritage List for England organization, the design and installation of these services should aim to protect the building and its setting without losing historic fabric, following the three basic principles of mitigation, minimization, and reversibility.
Mitigation generally means reusing existing service routes, using alternative routes for services through voids under floors or above ceilings, and using existing features, such as moldings or balustrades, to conceal services like pipework and cabling. It also advocates locating new or additional items discreetly where their function is not compromised, using wireless technology for controls to eliminate the need for hard-wired connections, and choosing accessible service routes and locations to allow for easy future maintenance, repair, and replacement.
Minimization involves performing the minimum amount of work that would disturb the existing fabric and, where necessary, reusing as much of the existing fabric as is practical. It also involves routing pipework, controls, or cabling through buildings in ways that might not be the shortest, most direct, or simplest.
Finally, reversibility is planning for the removal of services at the end of their useful life as well as their installation, to reduce potential harm to historic fabric. This includes detailing each intervention, such as holes and fixings, and noting that fixings into mortar joints may be more appropriate than into brickwork or masonry, which cannot be so readily repaired.
This article is part of the ArchDaily Topics: Refurbishment, proudly presented by Sto. Extending the lifespan of buildings reduces cost and environmental impact, avoiding demolition or more substantial interventions in the future. Sto's products for facades, facade refurbishment, crack repair, waterproofing, and concrete restoration systems are used on heritage buildings, adaptive reuse projects, renovations and maintenance of new buildings all over the world. Every month we explore a topic in-depth through articles, interviews, news, and architecture projects. We invite you to learn more about our ArchDaily Topics. And, as always, at ArchDaily we welcome the contributions of our readers; if you want to submit an article or project, contact us.
