In this section
In this guide, the words 'must' or 'must not' are used where there is a legal requirement to do (or not do) something. The word 'should' is used where there is established legal guidance or best practice that is likely to help you avoid breaking the law.
Background
Spray foam insulation is a liquid polyurethane that expands into a dense foam; this can be sprayed into walls, floors and most commonly in roof spaces. Its intended purpose is to improve home energy efficiency, reduce energy bills and lower greenhouse gas emissions by making a home more thermally efficient.
Spray foam insulation comes in two main types:
- open-cell foam:
- lightweight, flexible and good for soundproofing
- closed-cell foam:
- denser; provides better thermal insulation and moisture resistance
Before installation, businesses should be aware that the use of spray foam can have significant practical implications concerning mortgage eligibility and potential property damage. This has made it a high-risk material for many lenders and surveyors, particularly if it has been applied incorrectly or without proper documentation.
Spray foam insulation, especially when applied to roof spaces, can:
- obstruct structural inspections, making it hard for surveyors to assess roof condition
- trap moisture, potentially leading to timber rot or structural damage
- impact ventilation, increasing the risk of condensation and mould