As we strive to make our buildings more energy efficient, retrofitting is set to play a vital role in repurposing existing buildings to help meet net zero carbon commitments.
There’s a focus on using the resources already present in our buildings, prolonging their life where possible rather than demolishing them to reduce carbon emissions, and recycling materials to be sustainable. Retrofitting is a useful tool in the battle to increase energy efficiency in the face of climate change and rising energy bills.
The significance of retrofitting has been highlighted by the AJ Retrofit Awards 2023, organised by The Architects’ Journal, which celebrate the design expertise involved in rethinking buildings and retrofitting imaginatively to cut the construction industry’s carbon footprint.
Let’s look at some of the amazing award-winning designs.
Category: The Architects’ Journal Retrofit of the Year Award.
The headline category has been won by London architectural practice Mikhail Riches for its work on the second phase of Sheffield’s Park Hill housing estate. It won in both the Housing and Listed Building £5 million and over categories.
The scheme involved upgrading the Brutalist fabric of the listed 1960s housing estate and fulfilled the key category aims of the awards including decarbonisation, social sustainability, and collaboration. From a learning angle, the new technology used can be employed on similar schemes and in retrofitting other major post-war buildings.
The retrofit work involved insulating existing brickwork internally and cleaning it externally, using a hygrothermal risk analysis of the wall to calculate optimal thermal performance. The scheme built on work carried out in the first phase of this redevelopment almost a decade ago which was nominated for the Stirling Prize. Tenants were consulted and put at the heart of decision making and note was taken of how they had personalised the building, especially through the use of colour. The project was designed to maintain the ethos of the original design, known as the `streets in the sky concept’ which was important in creating a community atmosphere.
AJ Retrofit Awards judges said:
This project fulfils a lot of objectives. There’s both a strong embodied carbon and social story.
While there were other great contenders, judges added that:
A lot sets it apart from the rest, including scale and occupant perspective.
Category: Higher education and campus.
A more open hub for London South Bank University’s London Road building on its Southward campus was designed by WilkinsonEyre. The centrepiece of this four-storey 1970s concrete-framed building is a library, surrounded by the university archive, teaching spaces, computer labs, and offices. New floors are suspended from large steel beams in the roof. Judges described it as:
Very impressive, and a really good approach with excellent data.
This scheme included internal reconfiguration of sports and catering facilities at the campus and refurbishment of lecture theatres, film studios, and cinema space. This project cost £47.3 million and was completed in April 2022.
Category: Hotel, retail, and leisure.
The brief for this restored dairy farm in West Dorset was to provide an accessible and sustainable mix of uses while retaining the character of the existing building. The original fabric was retained as far as possible and left exposed. Reclaimed materials were used in the retrofit process, along with low-carbon products such as cork and wood fibre insulation which reduces heat loss. Existing openings were re-used, and glazing was subdivided by timber mullions that filter sunlight. Inside, there’s space for wheelchairs, switches are installed at an accessible height and there are vibrating fire alarms for the hard of hearing.
The courtyard was planted with trees and shrubs and the whole scheme connects to its surroundings, which include a new woodland pasture. Judges described it as:
A wonderfully inclusive rural retrofit.
The project cost £2.6 million and was completed in April 2022.
Category: House up to £500,000.
A 1930s bungalow in Bradford-on-Avon, Wiltshire, was transformed on Passivhaus principles into a contemporary, sustainable home through alterations to create a light and open living space. Energy efficiency measures have dramatically reduced energy bills as a result. Achieving the high levels of airtightness required involved using spray-foam underfloor insulation and adding external wall insulation via high-performance recycled mineral fibre to the timber frames, which allowed the architects to retain much of the internal fabric while improving the house. Judges said that while demolishing the house and starting again would have been the easier option, the project set a precedent.
Category: House £500,000 and over.
This 1960s house was saved from possible demolition and renovated to become a new family home. At one point it was almost lost to an overgrown garden, but the undergrowth and 1980s additions were removed to allow a return to the original checkerboard pattern of pavilion structures. To add space, extensions have been added and the garden replanted. Judges said the scheme could have gone further in terms of sustainability such as going electric, but they said it was sensitive and `ungreedy,’ retaining its sense of space.
Category: Listed building up to £5 million.
Visitor facilities at a 280-hectare country park near Eastbourne were extensively upgraded in this £1.9 million project which involved repurposing existing buildings and upgrading them environmentally. Three listed buildings in a courtyard setting were retrofitted to provide a new visitor centre and café.
The scheme included internal wall insulation, roofs, ground floors, and thermal double glazing, while independent lining structures were made from wood and sheep wool. A ventilated void was created between the existing fabric and the new insulated lining to control condensation problems and also to make future dismantling easier. Judges praised the scheme’s:
Impressive operational performance.
Category: Workplace £5-£10 million.
Many of the original Edwardian features of this pair of connected industrial buildings in Hackney were retained, including brickwork, steel-framed windows, timber floors, cast iron, and concrete. A new storey was added to both buildings in this low-carbon retrofit. The retrofit process has resulted in a spacious workplace providing studios for small businesses; it can be let by the individual studio or on a multi-let basis.
Retrofitting: the way ahead for our building stock.
Architects are evidently taking great strides in terms of the ingenuity and materials they can apply to retrofit, which is likely to become more prevalent as we reinvigorate dated buildings to cater to our future needs.
The retrofit work featured in the AJ Awards will inspire many. Housing associations, local authorities and the construction industry are all prioritising energy efficiency measures and introducing new technologies including heat pumps, solar panels and solid wall insulation to reduce energy consumption and carbon emissions.
With the realisation that it’s better to retrofit than demolish, retrofitting is set to rapidly gain traction, and the innovative thinking behind the stunning projects highlighted above is leading the way.
