As part of our commitment to tackling energy inefficiency in social housing, PiLON delivered our first standalone whole house retrofit pilot for Stevenage Borough Council. Over a three-month period, we transformed a thermally outdated end of terrace bungalow, into a high-performance, energy-efficient property – all while the resident family remained in occupation.  

Scope of Works 

The property was suffering from damp, mould, and excessive heat loss, and required a comprehensive programme of works to improve thermal performance and occupant comfort. This was identified in the Retrofit assessors report, where a subsequent design was put together by a Retrofit Designer. The scope included:

• Scaffold erection to safely carry out external improvements and designed to include a tin hat, and monaflex for weatherproofing

  

• Full roof strip-out and installation of a warm deck pitched roof system including Brickwork design alterations to raise the roof to make space for the new insulation, this involved removing one course of bricks around the circumference of the property and installation of three new courses providing the required room to enhance the thermal efficiency.  
• Photovoltaic (PV) solar panels, supplied and installed 
• Ventilation upgrades, including Vent Axia mechanical systems in all rooms 
• Existing cavity wall extraction and new cavity wall insulation 
• New High-performance double-glazed windows and doors 
• Trickle vents added to the conservatory to improve airflow 
• A full Electrical Installation Condition Report (EICR) 
• Bird block installation (<20m) around the perimeter of the PV array 
• Installation of rainwater goods
• Mains-operated multi-alarm system with RF module installed in the loft 
• Temperature and humidity sensors to monitor indoor conditions post-completion 

The warm deck system – typically reserved for flat roofs, was innovatively applied to a traditional pitched roof to support the government’s goal of achieving EPC rating C across all social housing homes. 

Challenges and Solutions 

The project commenced with a pre-start meeting and a clearly defined programme. 

With a total cost of £58,000, the team anticipated some challenges along the way – though a few unexpected issues did arise during delivery. 

One of the most critical moments came during the roof strip-out, undertaken while the residents remained in their home. Once exposed, our team worked quickly to limit the time the property would experience rapid heat loss, installing the first layer of insulation the very next day, successfully stabilising internal temperatures and receiving praise from both the resident and the client. 

Working closely with Building Control, there was also a query over the depth of the insulation, and further decision around the method of installation, this was quickly resolved by the Retrofit Designer, who clarified condensation considerations. This was signed off by Building Control, and the project continued.

Another challenge emerged once the roof had been stripped, showing that the original designs were unsuitable, having not been based of accurate drawings.  Working collaboratively, our team requested an urgent redesign and adapted on-site operations to incorporate the revised details without delaying progress. 

Resident Feedback 

“The works carried out have improved the warmth within the home. We can now retain heat after the heating has been turned off… Everyone from the scaffolders to the internal contractors were professional, polite, and careful inside the home. 

Any contact I had with any of the workers was positive, nothing seemed too much for them. They answered any queries I had to the best of their knowledge and were extremely polite at all times. 

I was very impressed with all workers, from both PiLON and their roofing contractor.”
Stevenage Resident

Collaboration and Delivery

Delivered on time and within budget, the project commenced with scaffold erection on 22 January 2025 and reached practical completion and handover by 1 April 2025. This successful delivery was achieved through strong collaboration, meticulous planning, and a proactive approach to site management. 

Key to maintaining momentum and alignment throughout the programme were:

• Consistent communication between our site team, Resident, Stevenage Borough Council, and all subcontractors 
• Weekly coordination meetings to track progress and address issues promptly 
• Daily site photography, including drone and geotagged imagery, to support audit trails and meet Trust Mark accreditation standards

All works were completed in accordance with government retrofit funding criteria, with rigorous quality assurance processes in place to ensure full compliance and enable the release of funding through certified back-end documentation. 

Outcome and Next Steps 

The property is now in a monitoring phase, with sensor data being gathered to measure temperature, humidity, and post-retrofit energy consumption. These insights will support future funding release and provide the foundation for rolling out additional properties under Stevenage Borough Council’s retrofit programme. 

With strong feedback from both the resident and the client, this pilot sets a new benchmark in delivering sustainable retrofit solutions in occupied homes – and demonstrates PiLON’s capability to adapt, innovate, and deliver on ambitious energy efficiency targets.