What was the problem?
The 650 mostly Victorian terraced homes are part of one of the UK’s largest Community Energy Saving Programme schemes. They were provided with measures including loft insulation, new boilers, heating systems and controls, draught proofing and external wall or cavity wall insulation to cut heating bills and reduce emissions. Our client, Go Warm, wanted a cost-effective, quick-to-install external wall insulation (EWI).
What was your approach?
We supplied ThermoShell solid EWI – a highly insulative expanded polystyrene layer covered with silicone render that gives all the properties a smart, white, uniform look. Installing EWI on a terrace is fast, as you can simply wrap a scaffold around it and there’s no need to go inside.
The terraces’ doors, windows and bay windows varied in design, so Knauf worked with installer Synergise to develop a set of simple details that would allow residents to replace or repair doors and windows in the future. This caused some controversy with the council, which was worried that any gaps around the insulation could create a cold bridge or lead to condensation, but without this, the system could be easily damaged and become less efficient, so the council soon agreed.
ThermoShell shields the exterior facade from the effects of weathering and delivers a U-value of 0.3W/m2K, which we estimate will save each property around £350 to £450 a year on heating.
Is expanded polystyrene the only insulation you can use for upgrading the exterior of solid walls?
Knauf Insulation also has its Rock and Rock Plus mineral wool versions of the ThermoShell EWI system. The three systems have several application benefits and performance characteristics, and can be installed onto solid wall properties – it just depends on the project itself. For larger projects where there is a tight deadline, EPS is easy to handle, resulting in quicker installation times, and also has a better thermal conductivity.