INCA EWI Case Study: Sandwell SHDF Wave 2.1

The Sandwell Council SHDF Wave 2.1 program represents one of the region’s most ambitious large-scale domestic decarbonisation schemes, targeting the improvement of over 200 occupied homes across Wednesbury and Smethwick. The project brief was clear: deliver a high-quality, compliant retrofit solution that would significantly improve thermal performance, reduce carbon emissions, and enhance the living conditions of residents. All within a highly constrained delivery timeframe. Incorporating all necessary measures to maximize efficiencies.

The project was initially awarded as a 40-home contract, then the scheme rapidly expanded to include the full 200 properties, a direct reflection of Prime Build Construction Group Ltd’s strong performance and delivery capability. This scaling-up required a significant mobilisation effort, including the deployment of over 120 operatives, of which more than 90 were specialist EWI installers, ensuring that program deadlines and quality expectations were maintained throughout.

At the core of the solution was the installation of the Johnstone’s Trade Stormshield External Wall Insulation system, selected for its proven thermal performance, durability, and suitability for retrofit applications. The system was finished with Johnstone’s Silicone Enhanced Topcoat, with approx. 2,000 tubs used across the scheme. This provided a consistent, weather-resistant, and beautifully pleasing finish across all properties.

One of the defining aspects of the project was the complexity of the existing housing stock. The homes presented a range of technical challenges, including displaced party walls, varied construction types, and complex roof geometries such as mansard designs. These conditions require highly detailed insulation design and precise installation techniques to ensure continuity of the thermal envelope and compliance with performance requirements.

Delivering the scheme within just Six months added further pressure, particularly given that all properties remained fully occupied throughout the works. Careful planning, sequencing, and ongoing communication with residents were essential to minimise disruption and maintain safety. Close collaboration with Retrofit Coordinators ensured that all measures met PAS 2035 requirements, demonstrating a commitment to best practice in retrofit delivery.

From a performance perspective, the project achieved a significant uplift in thermal efficiency across all homes, contributing to reduced energy consumption and improved occupant comfort. The properties included within the scheme were fully assessed and a “whole house” approach was adapted.

Multiple measures were assessed and installed following approved project designer recommendations. Including Solar, Electrification measures, Loft Insulation in addition to the specified EWI System. 

 The application of a silicone render system provides long-term protection against weathering, ensuring durability and reduced maintenance over time.

What sets this project apart is not only its scale, but the quality and consistency achieved under tight time constraints and challenging site conditions. The ability to expand the program while maintaining installation excellence highlights the strength of both the system and the delivery team. Whilst focusing on multiple measures to maximize efficiencies.

Residents and stakeholders have responded positively to the transformation. As client Sandwell MBC noted, “This scheme has delivered real change at scale. Improving homes, reducing energy demand, and doing so with an exceptional level of professionalism and care is a testament to the team and the word they did.”

The Sandwell SHDF Wave 2.1 program stands as a benchmark for large-scale retrofit delivery, combining technical excellence, logistical precision, and meaningful environmental impact in a way that exemplifies best practice in the EWI sector.