Cavity wall insulation has been retrofitted into around 17 million homes across the UK, promising improved energy efficiency and lower heating costs. However, a growing number of homeowners are now dealing with the consequences of improper installation. OSCAR Onsite sheds light on the situation, the rising concerns, and the steps you can take to address the issue.
OSCAR – On Site Cavity Assessment Report
Millions of UK Homes Affected by Cavity Wall Insulation Failures
The widespread installation of Cavity Wall Insulation (CWI) was intended to enhance energy efficiency and reduce household heating expenses. However, reports from industry specialists and property owners suggest that up to six million homes may have incorrectly installed insulation, raising significant concerns. Despite the scale of the issue, it has yet to receive the urgent recognition it deserves.
With some of OSCAR Onsite’s leading member firms also taking the story to a Parliamentary Review Board, the BBC and other national news outlets, and OSCAR Onsite in collaboration with Stakeholders and Government and now having the issues and OSCAR mentioned in parliamentary debates, the problem is starting to get the attention it deserves.
With the UK experiencing increased rainfall and changing weather patterns, the likelihood of insulation failure has risen, bringing about serious energy, environmental, and health-related repercussions.
Over the past year, several reports have highlighted severe issues with External Wall Insulation (EWI), leading to 39 firms being suspended from TrustMark accreditation. This development has triggered a government-led review, yet discussions surrounding CWI failures remain inadequate.
Feedback from industry professionals suggests that CWI failures may be more extensive than initially believed, underscoring the need for stricter industry regulations and greater public awareness. MP Hywel Williams has repeatedly raised this issue, advocating for OSCAR Onsite’s involvement in rectifying the industry’s shortcomings.
The Impact of Cavity Wall Insulation Failures
When CWI fails, it loses its thermal efficiency, leading to a higher U-value and increased energy consumption. This, in turn, results in:
- Higher heating costs – ineffective insulation forces homeowners to use more energy to maintain indoor temperatures.
- Increased carbon footprint – greater energy consumption leads to higher greenhouse gas emissions, contradicting the UK’s environmental targets.
Beyond financial and environmental consequences, failed insulation can also cause structural and health hazards, including:
- Damp and mold growth – moisture infiltration leads to damp walls and ceilings, damaging internal finishes and creating ideal conditions for mold.
- Health risks – prolonged exposure to damp environments can aggravate respiratory conditions, allergies, and weaken immune systems.
Why Does Cavity Wall Insulation Fail?
A major cause of CWI failure is water ingress—when moisture from the outside seeps into the insulation material within cavity walls. Over the past decade, UK rainfall has increased by 10%, significantly raising the risk of water infiltration.
Homes with compromised weatherproofing—such as deteriorated brickwork, ineffective seals, or defective guttering—are particularly vulnerable. Once moisture enters the cavity, the insulation’s effectiveness diminishes, leading to accelerated heat loss and higher energy bills.
How to Check the Condition of Your Cavity Wall Insulation
OSCAR Onsite provides a Cavity Wall Insulation Condition Inspection Survey, designed for homeowners, landlords, local authorities, and housing associations. This survey delivers a comprehensive assessment of both external and internal property elements to pinpoint vulnerabilities that could impact insulation integrity.
- External evaluations examine fascia, soffits, gutters, downpipes, windows, doors, brickwork, pointing, and damp-proof courses.
- Internal assessments utilize borescope technology to inspect the cavity and insulation condition.
Following the survey, property owners receive a detailed report outlining their home’s weatherproofing status, identifying any potential concerns, and recommending remedial actions to prevent water ingress and protect insulation.
Industry Experts Leading the Way
As a multi-award-winning organization, OSCAR Onsite is the UK’s leading authority in cavity wall insulation surveying and extraction. Over the past decade, the company has trained over 250 independent insulation firms across the UK, ensuring they adhere to industry standards, compliance regulations, and best practices for CWI extraction and clearance.
We are also an Approved Training Academy, having written the 2 qualifications for this industry:
https://oscaronsite.co.uk/course/nvq-level-2-in-cavity-wall-surveying-or-inspection-occupations/
https://oscaronsite.co.uk/course/nvq-level-2-in-cavity-wall-extraction-clearance/
A Collaboration with RICS
The Cavity Wall Insulation Condition Inspection Survey has been designed in collaboration with RICS members (Royal Institute of Chartered Surveyors), combining OSCAR Onsite’s expertise with industry-leading assessment standards.
Book Your CWI Condition Inspection Survey Today.
