spray foam insulation in loft

Spray applied foam insulation has emerged as an option for insulating residential properties in the UK. Whilst this type of insulation has energy saving capabilities due to its insulating properties, its application can cause significant issues including dampness, decay and fungal infestation. The concerns regarding the use of spray foam insulation are so severe that in many cases, mortgage lenders are refusing to lend on properties where it is identified.

This blog aims to provide an in-depth understanding of spray foam insulation, discussing what it is, when it is used, and potential issues that may arise.

What is Spray Applied Foam Insulation?

Spray applied foam insulation, also known as spray foam, is a type of insulation material that is applied using a spray gun. It is made by mixing two components, polyol resin and isocyanate, which create a chemical reaction resulting in a foam-like substance. This foam expands rapidly upon contact, filling gaps and creating an airtight seal.

The material has been used for more than 30 years, despite criticism, because of its effectiveness at insulating buildings and stopping air leaks.

In recent years, it has been reported that issues have arisen in properties where spray foam insulation has been applied within the roof structure and to the underside of suspended timber floor structures.

The application of spray foam in these areas increases the risk of condensation and decay due to restricted air flow and ventilation to the structural timbers. When applied to the underside of a roof, spray foam can also conceal penetrating dampness issues, which if left undetected can manifest in decay and fungal infestation.

Unfortunately, spray foam insulation can be difficult to remove once it’s been installed. The best way to remediate is removal, which often means stripping the roof (especially if the roof is not under felted).

The potential for widespread damage, along with the upheaval required for removal, has led to properties with spray foam insulation being deemed unsuitable for lending in most cases.

This is obviously having a significant impact on the value of affected properties.

Inspections undertaken for mortgage valuations don’t always look in the roof void, which could prove a costly mistake. It is therefore extremely important to instruct a detailed Level 2 or Level 3 Survey, undertaken by a Chartered Surveyor, when buying a house in order to ensure that spray foam insulation is identified. This can help to avoid inheriting a house containing spray foam insulation, that may either develop serious structural issue in the future, or leave you with an expensive problem to resolve.

For further assistance or guidance from our Chartered Surveyors, or to obtain a quote for a property survey, please get in touch.

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