INCA Case Study: Welwyn and Hatfield SHDF

Project Overview

As a trusted leader in External Wall Insulation (EWI) solutions, the Welwyn and Hatfield Social Housing Decarbonisation Fund (SHDF) project highlights K Systems’ commitment to technical excellence and sustainability, along with our collaborative approach in solving some of the most complex retrofit challenges in occupied social housing.

Delivered in partnership with Morgan Sindall Property Services, this scheme demonstrates how intelligent system design, fire safety compliance, and aesthetic sensitivity can be balanced to drive successful outcomes for both residents and stakeholders.

Construction Challenge

The Welwyn and Hatfield SHDF scheme presented a range of construction challenges, including:

• Fire break design: Ensuring rigorous compliance with fire safety standards was a key hurdle. The complexity of integrating fire breaks within existing façades – particularly around shared access points such as ginnels – required careful detailing and on-site coordination.
• Occupied properties: Retrofitting while residents remained in situ meant managing disruption sensitively. Our team provided on-site technical advice to ensure work progressed with minimal inconvenience, helping to maintain high levels of tenant satisfaction.
• Customer satisfaction and finishes: Expectations around final finishes were understandably high. Our team worked to align the visual aspirations of Welwyn Hatfield Borough Council and residents with the technical constraints of the systems used.
• Budget and cost control: Delivering a high-performing, fully compliant system while maintaining value for money was a constant consideration. We supported Morgan Sindall with specification support and material guidance that maximised both performance and budget efficiency, achieving a high level of fire performance (A2, s1-d0) whilst utilising a cost-effective thin coat render.
• Conservation design at Attimore Close: This area featured stone cills and banding that fell under conservation planning requirements. Achieving a seamless integration between insulated and non-insulated properties was critical to maintain architectural coherence. K Systems’ ability to ‘finesse’ the detail design contributed significantly to the visual success of the project, so much so that BTS is undertaking an independent case study on the aesthetic treatment of Attimore Close.

System Specified and Why

Given the council’s fire safety restrictions, K Systems’ Mineral Wool EWI system was selected as the optimal solution. This non-combustible, high-performance system offered robust fire resistance, making it ideal for this high-density, occupied housing environment. Our system was also chosen for:

• Thermal efficiency: Delivering outstanding U-value improvements to help reduce fuel poverty.
• Design flexibility: Accommodating architectural features like stone cills and banding.
• Fire performance: Meeting stringent compliance standards including fire breaks and ginnel detailing, achieving A2, s1-d0 fire classification.
• Durability and finish: Providing a clean, consistent aesthetic that uplifted the appearance of entire streets while ensuring long-term durability.

Our technical team provided bespoke detailing and conducted on-site pull-out tests to confirm the suitability of fixings, particularly in complex areas such as shared access zones and mixed substrate façades.

Testimonial

“This refurbishment was a highly complex undertaking, involving intricate technical detailing and bespoke specifications across multiple properties.

“Collaborating closely with the K Systems team enabled us to meet the client’s expectations precisely. Every element of the project was executed with excellent care and professionalism, underpinned by K Systems’ unparalleled expertise.

“The end result is a collection of properties that not only have an exceptional thermal performance but also stand out with striking visual appeal.”

Mark Keen, Managing Director, BTS

Conclusion

The Welwyn and Hatfield SHDF scheme exemplifies the core values of K Systems – technical leadership, customer-focused collaboration, and a commitment to safer, more sustainable homes. By expertly navigating fire compliance, conservation constraints, and live-site challenges, we not only delivered an outstanding EWI solution – but one that residents, contractors, and the local authority can be hugely proud of.