Non-Traditional Housing Retrofit, East Leake, Nottinghamshire

Project Overview

Background

Metropolitan Thames Valley Housing owns or manages over 57,000 homes across a large part of England – predominantly the South East, the East Midlands and the East of England. It seeks to provide its residents with affordable housing, backed by a range of care and support services.

This project focused upon 80 homes in East Leake in Nottinghamshire, the majority of which were built to the BISF archetype. This is an old design that features a steel frame with relatively thin concrete infill panels. It is known to deliver poor thermal performance so the client was keen to introduce energy-efficiency improvements. These included the installation of an external wall insulation system, amongst other measures such as the replacement of windows and doors.

Brief

The purpose of the scheme was to raise the EPC ratings of the various homes from an average of band D to at least band C. By installing external wall insulation, together with an attractive mineral render, the project team sought to improve the buildings’ thermal insulation, their airtightness and their overall appearance.

Design and Specification:

In accordance with PAS standards, the EWI system design and the schedule of works were developed on the basis of property-by-property inspections, which helped to determine the condition and integrity of the properties’ various substrates. Permarock technical staff carried out their own inspections of the steelwork and the concrete panels and foundation slabs, and they conducted pull-out tests to verify that the chosen system could be affixed securely.

From an early stage, Permarock technical staff worked with the client and the installer, Sustainable Building Services, to design systems and detailing that would deliver the necessary improvements, without the risk of cold-bridging. The specification called for the use of Permarock Mineral Fibre Insulation in thicknesses of 50 mm and 100 mm, over which would be applied Permarock SiliconeUltra K-Finish.

.

System Characteristics:

The Permarock Mineral Fibre EWI system typically delivers a significant improvement in the thermal performance of non-traditional buildings walls. It is both adhesively bonded and mechanically affixed to the substrate to ensure excellent resistance to wind-loading. Featuring an Ecopoints Score of 0.10 (m2) – an “Excellent” rating, and thermal conductivity of 0.036 W/mK, it may be used on retrofit projects that seek to achieve the highest standards of energy efficiency.

Permarock’s SiliconeUltra K-Finish is a high performance through-colour decorative render. It resists the accumulation of dirt, which it tends to shed through the normal action of weathering. It also resists the growth of unsightly mould and algae, so it retains its bright appearance for longer than conventional render materials.

For this scheme, the client selected a variety of shades from the 500 available in our A1 Colour Range. Made from inorganic pigments, all colour choices are highly stable and maintain their brilliant appearance for much longer than conventional paints and coatings.

Installation:

The installation was completed on time and on budget in the spring of 2025. Our technical team supported the installers by undertaking regular site visits for the duration of the project, and by providing telephone-based assistance whenever required.  They also delivered various on-site project specific training sessions for installation operatives, and provided technical support throughout the scheme.

Result:

The project has enhanced the appearance of the refurbished properties and is expected to meet or exceed all EPC targets.

Consequently, residents can enjoy warmer, more comfortable living conditions and, over time, substantial savings on routine energy costs.

Client
Metropolitan Thames Valley Housing
Specifier
Sustainable Building Services (UK) Ltd & Rendserve
Substrate
Steel-frame & Concrete (BISF)
System
Permarock Mineral Fibre External Wall Insulation Systems
Finish
Permarock SiliconeUltra K Finish