Brits considering improving the energy efficiency of their homes are warned to do their research before using spray foam insulation.
The popular form of insulation has been widely used by homeowners for several decades – but if installed incorrectly it can cause problems when they come to sell or get a new mortgage.
It is estimated that a total of 250,000 households have used spray foam insulation in recent years, and some are now suffering the dire consequences.
Quick fix: Spray polyurethane foam is a type of attic insulation that 250,000 households have used in recent years in an effort to make their homes more energy efficient.
Improper installation can pose a structural hazard to homes and lead to expensive repair bills. For example, the foam may not provide the proper ventilation, which could cause the roof frame to rot.
Issues like these are picked up during construction surveys and pointed out to potential buyers, which may deter them from buying the home.
Lenders may also be reluctant to grant new mortgages. In November, Britain’s biggest building society, Nationwide, warned it could reject mortgage applications on homes where spray foam insulation had been installed incorrectly.
The average household’s gas and electricity bill of £3,000 from next month, many homeowners will be looking for ways to cut costs by making their homes more energy efficient – of which spray foam insulation is one option.
In response to growing concerns about cowboy businesses and poor practice in the industry, the Royal Institution of Chartered Surveyors (Rics) today launched a comprehensive guide to advise Britons on the use of insulation in spray foam.
The guide explains the effects spray foam can have on roof structure, thermal performance and property value, as well as the do’s and don’ts when installing insulation in a home .
Unregulated: If spray foam is installed incorrectly or sprayed into the wrong roof space – with leaks or defects, or with a problem with condensation – it can lead to rot
Sam Piplica, Senior Building Standards Specialist at Rics, said: “We are pleased to bring this free consumer guide to spray foam insulation to the public.
“Rics’ mission is to serve the public, therefore, the main purpose of the guide is to educate and raise awareness of potential problems with spray foam, so people can make informed decisions based on the research and due diligence.
“Rics is also part of an industry task force on this issue to help not only our members, but the industry as a whole improve their products and services.”
What should owners know?
Spray foam, also known as SPF, is a form of insulating material that can be applied to attics, walls, and floors.
It is installed using a spray gun, which can be advantageous when working with unusual designs and tight spaces.
While adding spray foam insulation can make a home warmer and reduce energy bills, it can also cause unwanted side effects.
For example, sealing in warm air can also seal in moisture and make roof repairs more difficult.
Many older homes in the UK – despite being poorly insulated – were built to breathe. Improperly installed insulation can inhibit this ventilation and lead to dampness.
Rics also advises homeowners to make sure they prioritize certain other home improvements before considering spray foam insulation.
For example, a property must be wind and waterproof before spending money on improving its energy performance. Adding insulation to a poorly maintained roof could accelerate the decay of any untreated wood roof structure, Rics says.
Risks of Spray Foam Insulation
1) Hidden problems
Some spray foam insulations can make it difficult to identify roof problems because they limit the view from the roof space.
Indeed, if the wooden roof structure is covered with spray foam, it cannot be fully seen or inspected.
For example, if there is a roof leak behind certain types of spray foam insulation, a homeowner may not notice it, which can lead to wood rot.
2) Humidity and condensation
Improperly installed insulation can lead to moisture and condensation, which can damage parts of a property.
For example, most pitched roofs on homes and bungalows are designed to be ventilated and spray foam is a modification of the original design.
Improperly installed insulation can negatively impact ventilation and lead to dampness and rot
A drafty attic above insulation at ceiling level is usually a dry attic. Air circulation balances water vapor to reduce condensation.
However, the spray foam creates a warm roof space. It seals gaps to prevent drafts and retains heat – but will also seal in moisture unless precautions are taken.
The Rics advises all homeowners to seek professional advice on how to manage moisture risks.
3) Energy saving
There’s a risk that installing spray foam insulation won’t have the desired energy-saving effect if it’s not done correctly, Rics says.
Although spray foam insulation is a better thermal insulator than the equivalent standard mineral wool attic insulation of the same thickness, existing attic mineral wool insulation can be supplemented if needed.
This can result in a warmer home than if the typical maximum level of spray foam was installed between the roof rafters.
4) Fire safety
Homeowners should be aware of the fire risk to their property when using spray polyurethane foam as insulation.
Spray polyurethane foam is generally a flammable material, which will only resist a small flame for a few seconds.
Although unused attics do not require fire protection, if a fire does occur, having spray foam will increase the likelihood and extent of damage to property and adjacent homes.
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