Ministry of Defence Housing – Rock Park

Project overview

Rock Park is a residential development comprising 42 service family homes owned by the UK Ministry of Defence. The properties formed part of a wider refurbishment programme delivered by the Defence Infrastructure Organisation to improve the condition, energy efficiency and long-term performance of military housing stock.

The works included a comprehensive external envelope upgrade alongside internal and roofing improvements, with external wall insulation playing a central role in improving thermal performance and occupant comfort.

The challenge

The project involved upgrading older masonry dwellings with poor thermal performance while meeting strict cost, programme and performance requirements. Key challenges included:

• Existing ‘no-fines’ masonry construction with a deteriorated rendered finish
• Very high pre-refurbishment heat loss through external walls
• A requirement to achieve a consistent post-installation U-value of 0.30 W/(m²K)
• Delivery of works across multiple occupied homes
• Installation during autumn and winter months, requiring weather-resilient materials

The solution needed to be robust, cost-effective and suitable for large-scale residential refurbishment.

The solution

A Wetherby masonry external wall insulation system was specified as a proven solution for upgrading solid-wall residential properties. The system was designed to suit the existing masonry substrate and deliver the required thermal performance.

The insulation specification comprised enhanced EPS boards incorporating graphite technology, allowing improved thermal efficiency at reduced thickness compared with standard EPS. This enabled the project to meet performance targets while maintaining cost control across the wider refurbishment programme.

The insulation was finished with Wetherby Four Seasons (4S) silicone render, selected for its improved resistance to rain, rapid curing properties and suitability for installation in variable weather conditions.

Installation

The works were delivered by Wetherby-recognised applicators Total Render Solutions Ltd, acting as main contractor, supported by PD&CL Building Services Ltd.

The EWI system was installed following Wetherby’s approved detailing guidance, ensuring consistent insulation coverage and robust junction detailing around openings, rooflines and damp proof course levels.

The Four Seasons render system allowed the works to proceed efficiently during colder and wetter periods, reducing the risk of wash-off and programme delays.

Finishes and detailing

The façade was completed using a silicone-render finish with a uniform painted finish, providing a modernised appearance while significantly improving weather resistance and durability compared with the original render.

The finished system delivers a low-maintenance external envelope with long-term resistance to moisture ingress and surface degradation.

The result

Following completion, the external wall U-value was reduced from approximately 2.15 W/(m²K) to 0.30 W/(m²K), representing a substantial improvement in thermal performance.

The upgraded homes benefit from reduced heat loss, improved internal comfort and lower energy demand, supporting the long-term sustainability of the Ministry of Defence housing estate.

Key facts

• System: Masonry external wall insulation
• Substrate: No-fines masonry
• Insulation: Enhanced EPS with graphite technology
• Finish: Silicone render (Four Seasons system)
• Fire performance: System appropriate for low-rise residential use
• U-value improvement: From ~2.15 to 0.30 W/(m²K)