OSCAR Onsite | Independent Technical Evidence
Building Stronger Protection for Home Improvement Customers
OSCAR Onsite has prepared a detailed response to TrustMark’s 2026 consultation, drawing upon experience in cavity wall insulation surveying, extraction, technical monitoring, training, independent clearance certification and the investigation of defective retrofit installations.
This resource brings together OSCAR’s recommendations, historical expert evidence and supporting material to encourage informed discussion about consumer protection, accountability and the long-term performance of home energy-efficiency measures.
Why This Consultation Matters
Energy-efficiency improvements should make homes warmer, healthier and more economical to operate. Where installations are unsuitable, defective or inadequately monitored, the consequences can extend far beyond the original installation.
Property construction, exposure, cavity condition, installation standards and product suitability.
Read moreThe need for competent, impartial inspection and reliable technical evidence.
Read moreThe difference between predicted savings, lost anticipated benefits and potentially increased heating demand.
Read moreFinancial protection, complaints, remediation, independent assessment and accountability.
Read moreThe disposal of failed insulation, recycling limitations and whole-life environmental consequences.
Read moreSurveyor training, contractor competence, permanent property records and independent clearance verification.
Read moreDocument Library
The following documents provide the original consultation context, OSCAR’s response and historical technical and legal analysis relevant to cavity wall insulation failures.
TrustMark's published consultation setting out proposed changes to registration, oversight, consumer complaints, financial protection and associated scheme arrangements.
Main Consultation Response
51 pages · 26 October 2026 · PDF
OSCAR's detailed examination of the proposed changes, supported by practical experience and recommendations concerning independent oversight, insulation quality, consumer protection, financial guarantees, technical monitoring and environmental accountability.
Accompanying Q1–Q20 Response
6 pages · 26 October 2026 · PDF
Public copy — personal information redacted
A specialist report examining the relationship between cavity wall insulation failure, anticipated energy savings, thermal performance and potential additional heating costs. Prepared in connection with an individual property and based upon specified supporting information and assumptions.
Legal advice considering the distinction between expert evidence concerning physical remedial works and evidence relating to potential energy or heating losses, together with associated issues of recoverability and proportionality.
Featured Evidence — Energy Loss
Homeowners are encouraged to install cavity wall insulation on the understanding that it will reduce heat loss and heating costs.
Where insulation is unsuitable, defective, incomplete, degraded or affected by moisture, the anticipated benefits may not be achieved. In some circumstances, associated defects and moisture-related deterioration can contribute to poorer thermal performance and increased heating demand.
The question is not simply whether the insulation should be removed. It is also whether the homeowner has experienced a measurable financial loss associated with reduced energy performance.
The 2018 Max Krangle report is presented here as a historical example of specialist analysis addressing these questions. Its calculations depend on the property-specific evidence and assumptions identified within the report itself, and it does not establish a universal loss figure that applies to other properties.
Predicted savings and actual energy performance are not the same thing.
Featured Evidence — Counsel’s Advice
In June 2018, counsel at Kings Chambers considered whether energy or heating losses arising from alleged cavity wall insulation failure could be treated separately from the physical costs of repairing a property.
The advice distinguished between the expertise required to assess building defects and remedial works, and the expertise required to assess energy-related losses.
It also considered the legal and procedural requirements relevant to the recoverability of expert evidence and associated costs.
Investigation and repair of defects, dampness and building-fabric damage.
Assessment of anticipated savings, heating demand and possible additional energy costs.
The need for appropriate expertise, causation evidence and consideration of the circumstances of each claim.
This document is counsel’s advice and not a binding legal precedent, a court judgment or an established ruling. It does not determine any individual homeowner’s entitlement to compensation.
The Environmental Cost of Failed Insulation
When cavity wall insulation is removed, the extracted material becomes a waste stream requiring appropriate containment, transportation and management.
Although mineral wool may be described as recyclable, there is an important distinction between clean manufacturing or construction offcuts and wet, degraded or contaminated insulation recovered from existing cavity walls.
The existence of recycled content in newly manufactured insulation does not establish that extracted domestic cavity wall insulation is being recycled.
OSCAR considers that the final destinations of extracted insulation should be properly recorded and independently verifiable.
Recyclable in principle does not necessarily mean recycled in practice.
Why the waste trail matters
Waste transfer records
Documentation recording what was removed from site, in what quantity, and where it was taken.
Authorised waste facilities
Confirmation that material was received by a suitably permitted or authorised facility.
Actual recovery outcomes
Evidence of what was genuinely recovered or recycled, rather than what is theoretically possible.
Landfill data
Accurate records where material could not be recovered, so the true environmental cost is visible.
OSCAR does not claim that all extracted insulation goes to landfill, nor that every insulation manufacturer rejects every category of recovered material. The point is that the actual destination of extracted insulation should be recorded and verifiable rather than assumed.
OSCAR’s Recommendations
An overview of the principal themes raised in OSCAR’s response. These are topic summaries, not a replacement for the complete numbered recommendations in the full consultation response.
The numbered recommendations, and the reasoning supporting them, are set out in full in OSCAR’s consultation response.
Read All Recommendations in OSCAR’s Full ResponseAbout OSCAR Onsite
OSCAR Onsite provides specialist services relating to cavity wall insulation surveying, extraction oversight, technical monitoring, independent clearance certification, professional training and contractor accreditation.
Through its work with homeowners, surveyors, contractors and other stakeholders, OSCAR seeks to improve competence, transparency and accountability in the assessment and remediation of cavity wall insulation.
Specialist condition inspection of existing cavity wall insulation, with photographic, evidence-led reporting.
CWI Condition Inspection SurveyIndependent confirmation that a cavity has been appropriately cleared following extraction works.
OSCAR Clearance CertificateTraining and qualifications for CWI surveying, inspection, extraction and clearance.
Training & QualificationsConsultation Updates
Entries are labelled to distinguish published events, editorial preparation and scheduled dates. This page is not used to publish unverified developments.
TrustMark published its consultation 'Building Stronger Protection for Home Improvement Customers'. The consultation is the subject of OSCAR Onsite's response.
This evidence library was prepared, bringing together OSCAR Onsite’s response, historical expert evidence and supporting material.
The published closing date of the TrustMark consultation.
Anticipated updates — not yet published
Contact and Further Information
If you are a homeowner, surveyor, contractor, solicitor or housing professional seeking information about cavity wall insulation inspection, extraction clearance or related technical services, OSCAR Onsite can assist.
OSCAR Onsite Ltd
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