Best Practice Guide: IWI for Retrofit

The Department for Business, Energy & Industrial Strategy (BEIS) has released new guidance on Retrofit Internal Wall Insulation.

BEIS has been in discussion with the industry throughout 2021, regarding the risks associated with installing less than 100% of internal wall insulation (IWI). The new guide has been produced for designers, surveyors, project managers and installers to address the issues raised. The review was led by Dr Sarah Price on behalf of Enhabit Ltd.

About the Guide

The new guide offers advice to aid in the assessment of internal wall insulation systems, particularly:

  • the viability of internal wall insulation or systems
  • the design of internal wall insulation
  • the selection of materials including hygrothermal aspects

There is a commentary about best practice methods for IWI and is recommended reading for parties undertaking such a system - regardless of whether it is being delivered under a Government scheme. There are dedicated sections of the guide targeted at key roles in the retrofit process (namely the retrofit assessor or surveyor, the retrofit designer or the retrofit installer).

Coming soon from BEIS

BEIS has also revealed longer term plans to expand on their suite of best practice guidance for retrofit. They intend to supplement the collection by covering other measures, including:

  • Room in roof insulation (RIRI)
  • Park homes (PHI)
  • Solid floor insulation (SFI)

Download the IWI for Retrofit Guide

You can download the guide for free on the BEIS website.