The Royal Institution of Chartered Surveyors (Rics) has launched a guide to update consumers on the latest guidance about the use of spray foam as a method of insulating residential properties.

Around 250,000 UK homes have spray foam insulation, where foam is applied using powered sprayers, which then expands and turns to a solid coating to insulate roofs, lofts, walls and floors.

The problem comes when it is used in roofs and lofts, where it has a tendency over time for the foam to trap moisture around wooden joints, which leads to rotting. The hardened foam can also warp wooden beams.

This has led to many mortgage and equity release firms refusing to lend to homes with this type of loft insulation.

The new Rics report, written by subject matter experts, aims to educate the public on the pros and cons of spray foam installation.

The guide covers topics such as what effects spray foam might have on a property’s roof structure, thermal performance and value.

In addition, it highlights the do’s and don’ts when installing insulation in homes and how Rics-accredited members can help assess your property.

It has been produced to inform the public about spray foam insulation after Rics notes that several Trading Standards cases highlighted poor standards of work, illegal modifications to listed buildings and high-pressure selling to vulnerable groups, such as the elderly.

Rics senior specialist in building standards Sam Piplica comments: “We are pleased to present this free consumer guide on spray foam insulation to the public.”

“Rics’ remit is to serve the public, therefore, the guide’s main focus is to educate and raise public awareness of potential issues surrounding spray foam, so that people can make informed decisions based on research and due diligence.”

“Rics is also part of an industry working group on this issue to help not only our members but the wider industry improve their products and services.”

At the end of last year, mortgage professionals warned homeowners to use a reputable provider when installing spray foam insulation to ensure they don’t make their homes unmarketable.

The comments were made after Nationwide announced it is seeing a sharp increase in the number of people installing spray foam to insulate roofs, lofts and attics to help ease the cost of living.

In November, The Mortgage Lender head of specialist distribution and key accounts Chris Kirby said: “The risk of unreputable companies undertaking the work is the ingredients used are unknown causing a potential impact on the structural integrity of the roof.”

Kirby suggested the current cost-of-living crisis will put a “magnifying glass” on this issue for many borrowers.

However, he said: “There is a lack of knowledge among consumers and borrowers.”

With the spray foam industry currently unregulated, Kirby stated: “More work needs to be done from a regulatory perspective to direct people down the right avenues to who they should be using or what type of insulation they should be looking to have installed.”

“The mortgage market should also provide some education on what type of insulation is accepted.”

“Borrowers do not want to be in a situation where they have spray foam insulation installed and then the property is no longer suitable for the current lender or other lenders in the market because of something that could’ve been avoided,” he added.