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Residential property specialist Spray foam insulation
Spray foam insulation is an increasingly popular method of insulating a home, improving energy efficiency and reducing energy bills. Typically used to insulate roof spaces, a technician applies the foam with a spray gun, which then expands to fill the required area, forming an insulating layer.
Green Homes Grant
Spray foam was one measure covered by the government’s Green Homes Grant scheme, which closed to new applicants on 31 March 2021. The scheme covered up to two-thirds of the cost of energy efficiency improvements, with a maximum government contribution of £5,000. Understandably, the scheme proved highly popular. Although spray foam was only one type of work covered under the scheme, it was a significant factor in some 250,000 homes in the UK now having this type of insulation.
Types of spray foam insulation
There are two types:
- Open cell: remains soft after setting and is not prone to condensation. However, it’s not as dense as closed cell spray foam, so it does not provide the same level of insulation.
- Closed cell: is rigid once set and, therefore, a better insulator than open cell spray foam. But it’s also a vapour barrier, reducing ventilation.
Is spray foam safe?
Alarmingly, for some considerable time now, I’ve received feedback from clients, agents, and surveyors highlighting that spray foam comes with a major health warning. And among the many recent news headlines are:
- Spray foam insulation ruined our house sale,
- They encouraged us to insulate our home. Now it’s unmortgageable, and
- Lenders reject homes with spray foam insulation
Indeed, research by the BBC shows that around a quarter of the UK’s biggest mortgage lenders now refuse to lend against affected homes. They highlight several problems:
- Some spray foam restricts the view within the roof space, making it difficult to identify problems with the roof. A timber roof structure covered with spray foam cannot be fully seen or inspected.
- As we all know, storms can damage roofs, and the presence of spray foam can sometimes make repair more difficult.
- If there’s a roof leak behind some types of spray foam, it may go unnoticed, resulting in rotting timber.
- Incorrectly installed insulation can result in uncontrolled dampness and condensation in parts of the property.
- Worryingly, polyurethane spray foam is a combustible material. Building materials are tested using BSI Standard BS EN 13501-1 with a typical polyurethane rating as Class E – Combustible, which ‘will only resist a small flame for a few seconds’. Therefore, you should be aware of the increased risk to your property when using polyurethane spray foam as insulation.
Before introducing spray foam, homeowners should always instruct a qualified professional to survey all roof parts, including thermal calculations and condensation risk assessments.
What are the alternatives?
The alternatives to spray foam involve reverting to the tried and tested, i.e. fibreglass insulation, cellulose insulation, or mineral wool.
Spray foam might seem attractive, but its drawbacks substantially outweigh the benefits for many homeowners. From health and environmental concerns, structural risks and mortgage complications, it can create more problems than it solves. Opting for traditional, proven insulation materials ensures a safer, cost-effective, hassle-free investment in your home.