Today the Royal Institution of Chartered Surveyors (RICS) released a ‘clear, impartial guide’ to spray foam insulation. This aims to be an informative guide for property owners who may be considering the use of spray foam to (typically) ‘seal up’ their roof against heat leaking out. Whilst I was aware of the document’s launch, it was still tricky to find, so do click here to access the RICS’ webpage from where the document can be downloaded.
The document helpfully sets out what spray foam is (flammable) and how it can improve the thermal performance of the property – which is possible, but not without its trade-offs. Principally, once spray foam is installed there is no going back! Sprayed to the underside of the roof construction – to the rafters and tiles – it remains in place and conceals any future inspection of the timbers. This can have long term implications for the management and integrity of the roof where the roof timbers become wet and start to rot owing to lack of ventilation to remove moist air.
You may have a listed property of ‘hybrid’ construction, with parts that are ‘very old’ and parts that are ‘newer extensions’, and find yourself considering spray foam for a portion of the roof space only, however, the advice is clear: for listed buildings spray foam requires approval before installation foam insulation. This therefore suggests it would be wise to apply this level of caution for buildings of any age, listed or not.
Having worked on heritage buildings which have had spray foam applied – often by the previous owner who has side-stepped the problem – the way to resolve this permanent feature is to address it sooner rather than later. This applies to any older property, not necessarily listed, which has had spray foam applied to the underside of the roof; it is more constructive to resolve the matter than to allow it linger on, “….out of sight, out of mind”. In this circumstance it is recommended to seek independent advice from a Conservation Architect who can assist to review your options, and guide the proposals through listed building consent, and ultimately, remedial works, particularly if the property is not listed, but pre-dates 1910.
This document is timely to assist greater understanding of how a knee-jerk response to making a property warmer can have downstream consequences, and should be considered as part of a ‘whole building’ approach to energy saving. To be informed is to be pre-armed, and I hope that being aware this document exists will help you to fend off spray foam installers’ cold-calls, and seek appropriate advice.