Tools for Transition: Retrofit Lessons for Housing

Retrofit at scale 

Transforming Homes, led by Professor Jo Patterson at Cardiff University's Welsh School of Architecture, focuses on 1920 to 1940 council built housing, which accounts for around 1.4 million homes across the UK. Patterson told delegates that retrofit has tended to be piecemeal, driven by funding for individual measures such as solar panels or heat pumps rather than a whole-house approach. The project is developing a design catalogue intended to move retrofit decisions beyond energy performance alone, covering layout, materials and long-term maintenance, and is testing this approach through demonstration homes in Bristol and Swansea. 

Dr Lucy McFadzean, a Research Fellow at the University of Exeter working on the project, described a resident in one of the demonstration homes who had lived with persistent mould and had come to regard it as normal, something to be cleaned off every two weeks. Through co-design workshops, the team identified the mould as a consequence of a design feature common to homes of that era, rather than a problem specific to the resident. The finding led to the resident joining her family's construction business to help deliver maintenance work on neighbouring homes. The example was used to illustrate a broader point made across the panel: that co-design depends on sustained contact with residents over time, not a single consultation, and that trust in home retrofit programmes takes time to establish, particularly given residents' previous experience of trades and disruption in the home. 

Materials and the retrofit supply chain 

A session on material reuse and waste examined the barriers to specifying bio-based and reused materials in construction. Dr Katherine Adams, technical director at the Alliance for Sustainable Building Products and a partner of the Transforming Homes project, said that of the organisation's members producing natural fibre insulation from materials such as hemp, wood fibre or lime, only three hold the certifications required by mainstream retrofit schemes. Certification costs, warranty requirements and building regulation sign-off were identified as recurring obstacles, independent of the performance of the materials themselves. 

The same panel discussed wool as an insulation material. Jayne Harkness, a sheep farmer and PhD researcher at Ulster University working with Ulster Wool, said the volume of wool processed through the British Wool system fell from around 23.5 million kilograms in 2020 to under 20 million kilograms last year, reflecting a decline in sheep numbers and a lack of investment in the sector. Favourite fact of the day – different sheep have different quality of wool, and Blackface Sheep wool is quite coarse therefore can’t be used for clothing.  However, it can be used for insulation!  Panellists agreed that reuse and bio-based materials face the same underlying issue as retrofit more broadly: established supply chains are well developed and cheap, and reused or bio-based alternatives cannot compete on upfront cost alone. Speakers argued that carbon savings, wellbeing benefits and programme savings need to be part of the business case put to clients and funders. 

Scaling from pilot to practice 

A parallel project, Design Hopes, led by Professor Paul Rogers at the University of Strathclyde and Professor Mel Woods from Dundee University, have worked with all 14 NHS Scotland health boards to develop reusable, plant-based surgical caps and gowns that fully biodegrade within ten weeks. Abigail Heijelaar, climate change and circular economy lead at NHS Scotland National Procurement, described taking the project team to a decontamination unit, where staff identified specific reasons a reusable product had not met operational requirements. She said the barrier to scaling reuse in healthcare settings is rarely the material itself, but the supporting systems: laundering, infection control sign-off and procurement processes built around single-use products. David Taggart of NHS Scotland's climate action delivery team made a similar point about surgical gowns, noting that although clinicians supported a reusable alternative, the laundering infrastructure needed to operate it at scale was not yet in place two years after a successful trial. 

Speakers across the day returned to this distinction between proving a solution and embedding it. Several noted that funding and policy cycles do not match the timescales needed for retrofit and material innovation to become standard practice, and that evidence requirements differ by audience: a finance director and a frontline member of staff need different arguments for the same change. 

What this means for housing providers 

The projects showcased at Tools for Transition point to a consistent set of conditions for retrofit and material innovation to move beyond pilot stage: sustained, resourced relationships with residents and frontline staff; certification and procurement routes that do not penalise reused or bio-based materials by default; and a business case that sets carbon, cost and wellbeing evidence alongside each other rather than relying on any one measure. The Tools for Transition exhibition, drawn from the four projects, runs at the Design Museum until 20 September 2026.

Image credit: Adobe Stock