Ingenious Retrofit Solutions Showcased at Green Sky Thinking Week

It was a full house at David Morley Architects last night for its fifth event focusing on sustainability and the fourth as part of Open City’s Green Sky Thinking Week. With members of the audience from across the built environment profession, including architects, designers, engineers, academics and students there was bound to be an invigorating discussion to the question addressed by our panel – ‘Retrofit – the New Area of Ingenuity?’ The panel included:


  • Morwenna Wilson, Project Director, Argent
  • James Starr, Development Manager, Grosvenor
  • Jennifer Juritz, Head of Environmental Design, David Morley Architects
  • Joel Gustafsson, Senior Engineer, Max Fordham


An introduction by David Morley took us briefly back to an event held last year as part of World Green Building Week which focused on the role of temporary structures in the regeneration of our cities. Whilst the benefits of temporary structures were highlighted, including the London 2012 Water Polo Arena, the recurring truth that most of the UK’s existing buildings will still be in use in 2050 was apparent. It is these existing buildings that are responsible for the majority of energy use and CO2 emissions. Whilst upgrading this existing building stock poses several challenges, with a bit of ingenuity, as shown by our four speakers, these challenges can be turned into opportunities.


Morwenna Wilson from Argent opened the discussion by highlighting that the seemingly simple yet ingenious fact of retrofit projects from an owner’s perspective is that they are a quick way of getting property back into the market. On the opposite end of the scale Morwenna likened working on retrofit projects to “a bit like being on Ready Steady Cook” in that you are given the buildings ‘ingredients’ and must work out how to use them best. She took us through several examples including the refurbishment of the Fish & Coal Building designed by David Morley Architects. Decisions to retain the internal character of the building is strongly led by the tenants and precluded the option of internal wall insulation. Rather, high performance windows are proposed and the designers intend to use much of the existing thermal mass to deal with heating and cooling. Existing chimneys are also ingeniously used to house services extracts. What makes this building unique, and indeed all of Argent’s buildings at King’s Cross, is the creation of a “sense of place” which is, after all what makes people want to live, work and socialise in and around buildings at the end of the day.


Continuing the Client perspective James Starr of Grosvenor reminded us of the ‘why’ of retrofit with the very notable fact that 45% of the UK’s CO2 emissions come from buildings and that 87% of the UK’s buildings will still exist in 2050. Grosvenor recognises the need to retrofit if we are to get anywhere near the government’s target of reducing CO2 emissions by 80% by 2050 and have comprehensive retrofit goals in place. Grosvenor’s particular challenge in London is that the vast majority of their estate is within Conservation Areas and some third of their buildings are Listed, of which 75% are Grade II Listed. Overcoming conservation barriers and facing indifferent occupier attitudes Grosvenor are using 119 Ebury Street as a pilot project to push the boundaries of sustainable refurbishment. A two year post occupancy monitoring programme is in place to benchmark the retrofit against a standard Grosvenor refurbishment built at 125 Ebury Street.


Now to question the designers themselves! Showing us the ingenuity of retrofit first hand Jennifer Juritz of David Morley Architects took us through a sample of David Morley Architects retrofit portfolio. From the Grade II* Velvet Mill at Lister Mills in Bradford with its bold rooftop penthouses to the green façade proposed for the non-listed Synergy House on Southampton Row. She explored the ‘how’ of retrofit including working within existing building forms, managing user expectations in terms of technology and comfort, avoiding harm to old buildings, reducing waste as well as energy and inviting post occupancy feedback. Jennifer explored these themes in more detail on 119 Ebury Street, where extensive tests were carried out in the building to give a sense of its thermal ‘personality’ to estimate the energy use and CO2 production associated with running the building. Windows, a common challenge in many retrofit projects, were here extensively tested and a mock-up room built for the consultation and planning process including various fabric options. Jennifer finished by alluding to the Practice’s aim of continual improvement, talking about the Brierfield Mill Masterplan which at the earliest masterplanning stages has included low and renewable energy studies. In conclusion Jennifer commented that “as designers, these project constraints become opportunities that excite and enlighten us, and we intend to continue exploring the retrofit theme in our sketches and visions.”


Following an explanation of the ‘how’ of retrofit from a designer’s point of view, Joel Gustafsson of Max Fordham took us through the technical details of the issues faced in services design. Many of the themes brought out previously: roofs, windows, chimneys and existing space were reinforced with the key point being that looking at services and fabric in isolation is fruitless. Services do however offer an excellent way to improve amenity and efficiency but ad hoc services are “ugly, difficult to maintain and inefficient”. Showcasing Trinity New Court, Cambridge, the Grade I Listed building currently onsite and being retrofitted to the highest possible standards, Joel described the elegant solutions used to conceal service needs, for example extracts located in existing chimneys. Concluding, Joel bought back to reality the enormity of the task with retrofit being the only way to ensure the improved efficiency of energy use to meet government targets or we’ll end up with over 20,000 museums, when what we need is more homes.


Opening discussion up to the floor Miles Attenborough from Aecom questioned the economics of retrofit projects and picked up on the point that many of the examples shown during the evening included rooftop extensions which inevitably adds rental value to the building.  One reason for this is the solid, often brick, structures many older buildings are constructed from which are capable of taking additional weight. Furthermore the roof is often in such disrepair with constant exposure to the elements that major reworks are required anyway. As David Morley expressed, it can be said that London’s existing buildings provide a habitable foundation for future new builds.


Luke Hughes, Luke Hughes & Company, followed up on the question of permanence and adaptability by asking ‘how do we design new buildings to think about retrofit for the future?’ Jennifer Juritz responded that the key factors are space, flexibility and robustness of materials. However, in taking a long-term vision there is also a need to start thinking in terms of ‘real’ costs rather than standard capital costs.


Picking up on a key issue with many retrofit projects Ian Bailey of Bailey Gomm asked the panel about their experience with conservation requirements and the challenges these posed in energy efficient design. The panel had very different experiences with new high performance double glazed windows in thermally broken frames being readily accepted for the Grade II* listed Velvet Mills but at Fish and Coal, a non-listed building located in a Conservation Area, Argent had to compromise on the high performance window initially proposed. Finally Ralph Swallow from Fluid Structures asked the panel for a quick ‘Yes or No’ answer to the question if retrofit projects are to become more mainstream “is current planning guidance sufficient?” Regrettably, but perhaps unexpectedly, all panel members answered ‘No’. However, what the evening’s proceedings showed us is that there are a number of enlightened clients who are willing to push the boundaries beyond building regulations with teams of experienced designers and consultants who are passionate about their work.


Combining technical ingenuity with creativity through retrofit has proven to be both possible and desirable. Retrofit is the basis for both the preservation and continued habitation of our existing buildings and therefore we cannot ignore it as a key factor in architecture today.


In David Morley’s concluding comments, he questioned whether we answered the topic of our Green Sky Thinking session, is Retrofit the New Area of Ingenuity? The panel and our audience undoubtedly agreed that it was!