The use of spray foam insulation in Scotland

Reading Time: 3 minutes


SPICe has received several enquiries in relation to the use of spray foam insulation in Scotland and the potential impact this can have on mortgages and the cost for homeowners to replace incorrectly installed insulation.

The Scottish Government funded Home Energy Scotland offer a heating grant and loan for thermal insulation, which can include spray foam. Households in England were able to install spray foam under the UK Government Green Homes Grant scheme, which has now closed.

The House of Commons Library has published a blog about the possible issues with spray foam and mortgages. This blog provides a Scottish perspective on the topic.

What is spray foam insulation?

Spray foam is an insulation material in liquid form. It is applied by a spray gun and expands to form an insulation layer. It is commonly installed in roof spaces, walls and floors to increase thermal insulation.

There are two types of spray foam: open cell which remains soft and porous after setting, and closed cell which sets to a solid and airtight layer.

Potential issues with spray foam insulation

Due to perceived risks of harm to the property some lenders are unwilling to offer a mortgage or equity release where spray foam is present in the loft.

If correctly applied, spray foam should not cause any damage to a property. However, if incorrectly installed, it may cause damage to the roof structure. This has led some lenders to have a zero-tolerance approach to properties with any type of loft spray foam insulation present.

The professional body Royal Institution of Charted Surveyors (RICS) published a consumer guide on spray foam applied to loft voids in March 2023.

According to the guide, incorrectly installed spray foam can prevent ventilation and result in moisture-related damage. It can hide issues and prevent access for surveyors to assess the condition of the roof. It can also make it hard to repair any damage.

To prevent any issues with lenders and surveyors, RICS recommends that homeowners opting to install spray foam keep all documentation, for example independent test certificates, and contract and guarantees from the installer. It also recommends those buying a spray foam insulated property to ensure that this paperwork is available.

Scottish building standards

Scottish Building standards are set out in the Building (Scotland) Regulations 2004. The ‘Building Standards technical handbook’ provide guidance on how to achieve the standards set out in the regulations. Guidance on insulation and air flow is provided in the chapter ‘Building insulation envelope’.

Homeowners and tenants may wish to check with their local authority building standards department whether a building warrant is required prior to installing spray foam insulation.

The RICS consumer guide advises homeowners to seek independent advice to decide if spray foam is appropriate for their property.

Cold calling companies

Trading Standards Scotland (TSS) warns of scammers who pressure homeowners into installing spray foam insulation. TSS advises against agreeing to have any assessments of the loft carried out by a cold calling company as they will not be impartial.

Before installing spray foam insulation TSS advises homeowners to:

  • consult with a mortgage advisor who is regulated by the Financial Conduct Authority

  • arrange an impartial assessment to find out which energy efficiency measures will benefit the property.

TSS recommends those considering home improvements to contact Home Energy Scotland for free and impartial advice on energy saving measures.

Scottish Government grants

Heating grants and loans for energy efficiency measures  in Scotland are provided by the Scottish Government funded Home Energy Scotland (HES).

HES provides grants and loans for some types of spray foam insulation. Details of the funding is available online, along with guidance for choosing the right installer. If installing solid wall, underfloor, flat roof or room-in-roof insulation HES requires that:

  • the installer chosen for the job is Trustmark or Green Deal registered

  • that the measure appears in the ‘recommended measures’ table of an Energy Performance Certificate (EPC) or Home Energy Improvement report.

HES refers customers to the Warmer Homes Scotland programme (WHS). Under WHS, properties that are considered appropriate can have spray foam underfloor insulation fitted by the manufacturer QBot. WHS is funded by the Scottish Government and installations are managed by Warmworks.

Options for homeowners experiencing issues with spray foam

Available options for those experiencing issues related to spray foam insulation include:

Lena Phalen, Enquiries Officer, SPICe

Blog image “View of buildings below Stirling Castle, Stirling, Scotland” by aaranged is licensed under CC BY-SA 2.0.