Restoring and upgrading listed buildings is a complex business. Remaining sensitive to the historic fabric while integrating 21st century engineering and servicing solutions which meet environmental demands requires careful planning.
Engineers from Max Fordham have been unravelling the challenges of this building type on some of the UK’s most beloved buildings. The teams behind Tate Britain, the National Museum of Scotland and Trinity New Court at Cambridge University share some of their secrets.
An important starting point is finding out how the building was originally designed to work.
“The Romans, Victorian and Edwardian designers generally knew how to make a building work without much need of M+E systems,” said Colin Hamilton, a senior partner at Max Fordham. “Peel back the years of layers of adaption and try to work with the original building designer’s intent. Uncover the existing services and service routes within the building and when you understand what is there use this knowledge to minimise any intrusion.”
Steve Kenicer, project engineer for the National Museum of Scotland, which was a winner of the UK’s most prestigious architecture prize, agrees. He says good space planning can achieve almost cost free energy savings.
“Services engineers can influence the arrangement of space and how different functional areas are distributed in a refurbishment of an existing building,” said Kenicer. “We think of ways to help the client and architect understand environmental performance of the existing spaces. Which functional areas work best in which part of the building? For example, kitchens need good access to the external perimeter. Galleries may need low light levels and stable conditions to protect collections. Public spaces benefit from good natural light and ventilation."
The National Museum of Scotland, designed by Gareth Hoskins Architects, focused on minimising energy consumption without compromising the museum’s needs or the historic fabric of this Grade-A listed Victorian building. Closely controlled environmental systems were designed only for galleries housing sensitive and temporary exhibits with unobtrusive security systems designed for the protection of valuable exhibits.
With major refurbishments occurring only rarely during the life of a building, it is critical to take a whole life cost view of the project, as well as consider future flexibility and access to plant.
“Often it is more expensive to retain plant and attempt to integrate new systems with existing equipment,” said Kenicer. “Usually it’s more cost-effective in the short term use new energy efficient systems as a replacement. “
“Look at options and plan access at an early stage,” he advised. “Heritage projects often involve re-routing services in new reduced service zones. We discussed access with the client and their maintenance team to understand their methods of work, logistical issues, and use of services during public events. Access to services can become restricted at a later phase - e.g. when floor space / ceilings are covered by specialist fit-out packages (exhibitions, kitchens, restaurants). Down-time is critical and expensive in the life of these busy public buildings.”
Joel Gustafsson, project engineer for Trinity New Court at the University of Cambridge added that the fabric of heritage buildings is mostly at risk of having untidy interventions when the maintenance team undertake small ad hoc interventions out of necessity as a result of compliance changes.
“Building in future flexibility when undertaking a more considerable programme of works makes it more likely the building owners can avoid unsightly/damaging interventions,” he said.
With the Grade I listed Trinity New Court at Cambridge University, designed in collaboration with architects 5th Studio, the challenge has been to persuade English Heritage to support the retrofitting of internal insulation.
“Our proposal to internally insulate took three years of modelling/monitoring/reporting/discussion and, against the odds, was agreed,” said Gustaffson. “Heritage aspirations should not mean impressive old buildings end up unusable and on the road to disrepair.”
From a design perspective, the team used the existing coal fire flues and chimneys to distribute air to and from the bedrooms. This has considerably reduced the extent they have had to interfere with the fabric.
Colin Darlington, senior partner in charge for Tate Britain, Max Fordham’s most recently completed heritage refurbishment, recommends refraining from dogmatism - whether dealing with the approach, the solutions or the requirements.
“We look to widen the ‘control bands’ of the environmental requirements of galleries suggested by clients,” he said. “By making use of existing voids and lesser-used spaces, we can make more efficient use of space. This has the benefit of, for example, removing the need for plant rooms and positively impacting project costs. It’s flexible thinking like this that can make the difference in a scheme’s viability."
The refurbishment of the Tate, led by architects Caruso St John, provides a fresh take on how art is displayed, driven chiefly by the need to reduce the energy demands for lighting and cooling.
The bespoke daylighting scheme in the galleries means visitors can see low and medium sensitivity paintings, normally viewed under artificial lighting, in the richer qualities of natural light. Displaying art in natural light is not new, as this is how collections used to be shown. But contemporary conservation standards for light levels make it very difficult to use these traditional arrangements, and an important consideration for the success of the scheme was the need to tightly control the light entering the gallery.
The solution devised for this project involves a fixed shading system that blocks direct sunlight while enabling as much indirect, diffuse light as possible to enter the gallery. This was achieved with a bespoke configuration of mid-pane capillary tubes – effectively a double-glazed sandwich of drinking straws shaped and angled to fit the path of the sun.
‘What visitors notice is whether the space looks and feels great, not how this effect has been achieved. I consider it a success when people don’t notice our hard work,” Darlington said.