INCA EWI Case Study: 35 Florida Street, Stevenage

35 Florida Street is a residential refurbishment project that successfully delivered both a significant improvement in thermal performance and a complete transformation of the building’s external appearance. The project was designed to address the need for enhanced energy efficiency, reduced heat loss, and a more contemporary, durable façade solution while ensuring minimal disruption to residents throughout the works.

The chosen solution was a high-performance External Wall Insulation (EWI) Direct Render system supplied by SPS Envirowall and expertly installed by approved contractor Stoneguard Ltd. The system comprised 90mm Cladwool insulation boards mechanically and adhesively fixed directly to the existing substrate, followed by a reinforced basecoat and silicone render finish. This specification provided a robust and efficient thermal envelope capable of significantly improving the building’s overall energy performance, achieving a U-value of 0.21 W/m²K.

A thorough assessment of the existing façade was undertaken prior to installation to ensure the substrate was suitable for the EWI system. Any necessary repairs and preparation works were completed to create a sound, stable, and clean background, ensuring long-term system performance and durability. The insulation boards were installed in a staggered pattern to minimise thermal bridging and maximise thermal continuity across the façade. Carefully selected mechanical fixings were used to suit both the substrate type and site exposure conditions.

Once the insulation layer was installed, a reinforced basecoat incorporating alkali-resistant mesh was applied directly to the boards. This stage was critical in delivering impact resistance, crack control, and long-term durability. Additional detailing, including corner beads, stop beads, and movement joints, was incorporated throughout the installation to achieve clean architectural lines while accommodating structural movement and maintaining system integrity.

The final silicone render finish was selected for both its visual quality and technical performance. Its water-repellent and vapour-permeable properties provide excellent weather resistance while allowing the building to breathe, reducing the risk of trapped moisture within the wall structure. The finish also offers a low-maintenance solution, ensuring the façade retains its appearance over time while contributing to the overall longevity of the building.

Particular attention was given to detailing around windows, sills, and interfaces with existing building elements to ensure a cohesive, watertight finish across the entire façade. Quality assurance inspections were carried out at key stages of the installation process, from substrate preparation through to the final render application, ensuring compliance with project specifications and industry best practice.

Despite operating within a challenging programme and tight project timeframe, strong collaboration between SPS Envirowall/Benx, Stoneguard Ltd, and the wider project team ensured the successful delivery of the scheme. Coordinated logistics and proactive site support, including regular visits from the Benx technical team, enabled all EWI materials to be supplied on schedule and installation works to progress efficiently.

Overall, the 35 Florida Street project demonstrates how a carefully designed and professionally installed EWI Direct Render system can deliver meaningful improvements in energy efficiency, sustainability, durability, and aesthetics. The completed development now benefits from enhanced thermal comfort for residents, reduced carbon emissions, and a modern, high-quality façade that significantly improves the appearance and long-term performance of the building.