Cotality and Bolton at Home partnered to transform 151 cold, damp 1920s social homes. By prioritising independent oversight the project used archetype mapping and a fabric-first approach - including EWI, cavity insulation, and ventilation upgrades. This rigorous coordination bridged the performance gap, resulting in warmer, healthier, and more cost-effective homes for residents.
Key Highlights:
Total Homes: 151 properties across 38 building archetypes.
Methodology: PAS 2035 compliance with a focus on rigorous site inspections.
Outcome: Eradication of damp and achievement of EPC C ratings.
The blueprint to doing it the right way
In recent months, the UK retrofit sector has faced a crisis of confidence. Reports of poorly installed insulation leading to damp and mould issues have dominated headlines, creating a narrative that insulation itself is the problem. However, the reality is far simpler: the issue isn’t the insulation; it’s the process.
At Cotality, we believe that when a project is underpinned by effective management, independent oversight, and professional coordination, the results are transformative. Our recent collaboration with Bolton at Home - one of the North West's larger social housing providers - serves as a blueprint for doing retrofit the right way.
The challenge: cold homes and complex needs
The project, managed by Bolton at Home, focused on improving 155 homes on one of Bolton's oldest estates. These properties, dating back to the 1920s, consisted of over 38 different building archetypes including both cavity and solid wall constructions and were notoriously difficult to heat.
Residents had been starting to report a issues with condensation and cold, leading to a reliance on multiple layers of clothing and blankets to stay warm. For the Bolton at Home team, the goal was to move beyond repairs and deliver a durable solution to these resident concerns , effectively addressing health issues and bringing homes up to an EPC C rating.
Recognising that this project would be expensive to deliver without grant funding, Bolton at Home sought and secured this through Greater Manchester Combined Authority's Social Housing Decarbonisation Fund (SHDF) Wave 2.
The Cotality approach: quality through coordination
Bolton at Home used Cotality’s Retrofit Assessment service to map archetypes amongst the housing stock. This service delivers 360° imagery of a chosen representative home, including measurements and key data such as make and model of boilers and location of consumer units and drainage.
This archetype mapping was used in conjunction with other measures to help the early-stage planning of the project, which followed a fabric-first approach:
- Insulation: External Wall Insulation (EWI) was the primary measure. Where cavity walls were discovered, Cavity Wall Insulation (CWI) was installed following extraction of old material. Additional loft insulation was also installed where there was the opportunity.
- Other measures: New windows and doors; ventilation upgrades where necessary
- Drainage: French drains were installed around homes to help dry out the walls.
Through the project, Bolton at Home partnered with Cotality for independent design and coordination. Bolton at Home believes in the need for independent oversight rather than a "turnkey" solution, supplemented by internal staff who monitored quality alongside PAS compliance requirements.
"My role is to coordinate the job from start to finish. For high-risk measures like external wall insulation, I complete site visits for every property. We measure windowsills, roof overhangs, and check for thermal bridges. If it’s not done correctly, there is a high chance of mould; we won't let residents sit in an environment that risks their health."
Rowan, a Retrofit Coordinator at Cotality, explains the importance of this oversight.
Doing the job properly: technical excellence
Bolton at Home believes that a successful retrofit project is won or lost in the details.
This includes:
- Rigorous site inspections: Checking that all ventilation is installed correctly and up to standard to prevent moisture build-up.
- A "Whole-House" view: Coordinating 100+ cavity wall retrofits and 50+ solid wall retrofits, ensuring that each property’s unique elements are respected.
- Independent oversight: Providing the "fresh pair of eyes" necessary to manage the performance gap between design and reality.
The impact: warmth, health,and happiness
The results of this professional and rigorous approach are transformative.
As the Bolton at Home Surveyor stated:
"The highlight for me is going from surveying a property that feels cold and damp, with people spending loads of money on the heating and still being cold, to going in and they're not using as much heating and the rooms feeling warm and dry. It really has made a difference to people."
For the residents, the project has been life changing:
- Immediate thermal comfort: One resident noted the benefits were felt "straight away," with her children no longer needing several layers of clothing.
- Financial relief: Another resident reported putting the heating on far less, creating a "cost-effective" home where heat stays even throughout the house.
- Health and wellbeing: The eradication of damp has created a healthier living environment, significantly reducing the risk of respiratory issues associated with mould.
A model for the future
While Bolton at Home’s Tim Barwood acknowledges that the PAS 2035 process is "administratively heavy", he views it as a vital requirement for success. By embracing this complexity, Bolton at Home and Cotality have created a successful model that demonstrates what is possible with partners working to a shared vision and a commitment to quality.
This project proves that retrofit doesn't have to be a risk. When you combine data-led asset management with independent, qualified retrofit assessors and coordinators, you don't just insulate a house - you improve lives.
