In South Bristol, VOR has been leading a PAS 2035-compliant retrofit programme across over 150 post-war Laing Easiform flats, funded through the SHDF Wave 2.1 scheme. Working in close partnership with Bristol City Council and Bristol City Leap, this project demonstrates how careful planning, technical rigour, and collaborative delivery can transform the energy performance, comfort, and appearance of social housing.
This blog takes you behind the scenes of the Easiform project, exploring the challenges, the approach, and the lessons learned along the way, from early assessments through to design, delivery and monitoring and evaluation.
The Challenge
The Easiform scheme presented several unique challenges. Each block of flats, arranged in pockets over a broad estate of varying flats and house types required planning permission for External Wall Insulation (EWI), which was promptly secured, but the sensitive post-war architecture meant every measure had to respect visual aesthetic.
Adding complexity, the retrofit programme spanned the transition between PAS 2035:2019 and PAS 2035:2023, requiring our team to stay ahead of evolving guidance, adapt processes, and ensure compliance. Mixed tenure, planning constraints, and community expectations demanded solutions that were both technically robust and socially considerate.
Craig Madders reflects:
“The key bits of information that were critical for this scheme came from the archives. Rather than drilling holes or guessing, we had all the base information, and on-site we were just validating the construction.”
Our Approach
Archetyping
From the outset, Easiform was a highly archetyped retrofit project, meaning the housing stock consisted of repeating blocks of four flats, which allowed for significant efficiencies in assessment and design.
“We instructed a full measured building survey of an entire block, including internal and external LiDAR. This enabled us to produce base plans for the archetype design,” says Phil Partridge. “Once the archetypes were established, the on-site retrofit assessments for subsequent blocks were significantly reduced. Assessors were furnished with floor plans, window dimensions, and radiator locations. The focus was on identifying deviations from the archetype.”
This approach allowed the team to pre-populate assessment data, dramatically reducing time on-site while ensuring that unique property-specific issues, like a ground-floor flat that had a patio door replacing a kitchen window, were fully documented for installers.
Thorough Research and Assessment
VOR’s approach emphasised comprehensive research and detailed surveys to remove uncertainty early in the process. Craig Madders explains:
“As much research and assessment data as you can capture, the easier it is to move through the design and delivery stages. We didn’t rush to design before fully understanding the building. Once the assessments were complete and we had the measured building survey, we could move on with confidence, knowing we were unlikely to have to adjust designs later.”
By combining archival research with measured surveys and energy modelling, the team could validate assumptions and plan retrofit measures with precision and peace of mind.
Pilot Properties and On-Site Collaboration
The team also identified pilot properties as a key early step in delivery. Phil Partridge highlights:
“We invested a significant amount of time on the pilot properties, focusing on detail and sequencing with all the installers. For example, the properties had precast concrete sills that couldn’t feasibly be removed, so we developed a solution to retain it while reducing insulation locally and ensuring thermal bridging calculations were correct. These early solutions tool box talks enabled repetition of best practice across the scheme.”
Site visits were more than observations – they were collaborative problem-solving opportunities. Craig Madders adds:
“The installers know that we’re going to visit the site, and we don’t just write a list of what’s wrong. We work with them to solve issues, check fixings, and ensure quality behind the finished render. It gives confidence to the client that the installation is high quality, not just technically compliant.”
Tiziana Di Ronco emphasises the role of communication:
“Across our projects, we’ve seen that frank and open communication between client, installers, and lead contractor is critical. Being honest about situations and solving problems together is a huge factor in successful delivery.”
Digital Tools and Coordination
The team leveraged Revit for all design documentation, improving accuracy and collaboration. Coordinating across retrofit coordinators, designers, assessors, the main contractor, and installers ensured that every stage – from assessment to installation – was well-managed and technically robust.
Key Measures and Outcomes
The Easiform retrofit included a comprehensive set of energy efficiency measures:
- Cavity Wall Insulation (BFM.1)
- External Wall Insulation (BFM.4)
- Loft Insulation / Loft Hatch (BFM.9)
- Pitched Roof Insulation (BFM.10)
- Replacement of Existing Windows (BFM.3)
- Replacement of External Doors (BFM.3)
- Ventilation Improvements
These measures improve energy efficiency, reduce heat loss, enhance resident comfort, and support wider social benefits, including improved streetscapes.
“We achieved energy performance below 90 kWh/m², which is challenging for flats. It demonstrates that a fabric-first approach, combined with thorough surveys and careful planning, works,” says Craig Madders.
Craig Madders
Lessons Learned
Key insights from the Easiform project include:
- Archetyping drives efficiency: Standardised housing allowed pre-population of survey data and faster delivery.
- Pilot properties reduce risk: Early, detailed work on the most challenging units enabled scalable solutions.
- Collaboration ensures quality: On-site engagement with installers prevents issues from becoming systemic.
- Communication is crucial: Transparent discussions between all parties avoid misunderstandings and enable practical problem-solving.
Phil Partridge adds:
“Even if an installation is technically compliant, the finish must meet the client’s standards. Having someone act on behalf of the client to ensure quality is vital.”
Collaboration and Impact
The Easiform project exemplifies successful collaboration between VOR, Bristol City Leap, and Bristol City Council. Residents benefited from continuity of presence and engagement, while the team ensured PAS 2035 compliance, quality assurance, and practical retrofit solutions.
A testimonial from Bristol City Leap sums up the project’s success:
“Working with the VOR team on the SHDF Easiform retrofit project has been seamless from start to finish. Their end-to-end service, from retrofit assessment through to coordination, design, compliance, and TrustMark lodgements, has given us complete confidence in delivery. The turnkey approach has ensured consistent quality, clear communication, expert guidance, and measurable outcomes for our residents and stakeholders.”
Bristol City Leap
Key Takeaways
The Easiform retrofit scheme demonstrates that careful planning, archetype-led efficiency, collaborative problem-solving, and technical excellence deliver measurable energy efficiency improvements and lasting social benefits.
