The routes that exist • Who pays • Where to complain

Getting failed insulation put right

If your external wall insulation was installed under ECO4 or the Great British Insulation Scheme, the government's position is that you should not pay for the repair. For other installations the route runs through the installer, the guarantee and formal complaint schemes. This page sets out each route and where to start.

Identify the problem first

98%

Homes with ECO4/GBIS external wall insulation estimated to have major issues (22,000–23,000)

29%

Homes with internal wall insulation estimated to have major issues (9,000–13,000)

£20,000

Usual guarantee limit for repairs; £25,000 for IAA guarantees since June 2026

£0

What the government says households should pay for these repairs

Figures from the National Audit Office report HC 1334 (14 October 2025) and the Department for Energy Security and Net Zero (17 June 2026). Links in the sources below.

There is no government compensation scheme

You may see adverts promising compensation you are "entitled to". Be careful. There is no government payout scheme for failed insulation. What exists is a free audit for external wall insulation under ECO4 and GBIS, repairs at no cost to the household, 25-year guarantees that pay for repairs, and formal complaint routes.

The guarantees do not cover other losses such as ill health, damaged belongings or loss of earnings. For those, get independent advice — Citizens Advice's consumer helpline is 0808 223 1133. We are not solicitors or a claims management company and we cannot handle or advise on claims.

Which route applies to you

External wall insulation under ECO4 or GBIS: TrustMark Find & Fix

TrustMark runs a free audit for every household that had external wall insulation under these schemes. If faults are found, TrustMark arranges for the installer or retrofit coordinator to fix them, and you should not be asked to pay.

TrustMark: 0333 555 1234 (option 1), onsitebookings@trustmark.org.uk
Repairs fall to the installer, then the 25-year guarantee, then in some cases the National Energy Foundation
TrustMark says it may take several months to contact every household

How the Find & Fix audit works

Internal wall insulation under ECO4 or GBIS: Ofgem's ECO contact centre

Not every home with internal wall insulation is audited. Government guidance is that no action is needed unless you have concerns; if you do, Ofgem's contact centre assesses them and can arrange an audit.

Freephone 0808 169 4447, Monday to Friday 9.30am to 4.30pm
ECOhelp@ofgem.gov.uk
Ofgem does not handle complaints itself, but routes concerns about these installations

Other work by a TrustMark-registered business: the complaints process

Complain to the business first, then to its TrustMark Scheme Provider. If that does not resolve it, the Dispute Resolution Ombudsman can decide the dispute for free.

The ombudsman takes cases once you have a final response, or 12 weeks after your first complaint, and within 12 months of it
It cannot help if the business has ceased trading, was not registered, or with compensation claims
TrustMark cannot help with work more than 6 years old (5 in Scotland)

Cavity wall insulation: the CIGA or IAA guarantee

Cavity wall insulation from a registered installer should carry a 25-year guarantee, often from CIGA or, for newer work, The IAA — your certificate names the provider. Report the problem to the installer first and escalate to the guarantee body if it is not resolved within 41 working days.

Remedial work for a confirmed defect is free, up to £20,000
Disputes over CIGA's decision can go to independent arbitration through CEDR within 12 months
The guarantee does not pay compensation

How CIGA guarantees work

Private work, or no guarantee responds: your consumer rights

Put the problem to the installer in writing. For contracts since 1 October 2015, the Consumer Rights Act 2015 requires services to be carried out with reasonable care and skill. If it cannot be settled, you can get advice and, if needed, go to court.

Citizens Advice consumer helpline 0808 223 1133 can advise and pass complaints to Trading Standards
Small claims: up to £10,000 in England and Wales, £5,000 in Scotland and Northern Ireland
Time limits apply: generally 6 years for contract claims in England and Wales, 5 years in Scotland — take legal advice on your own case

What to gather before you complain

Installation paperwork

Installer's name and the date of the work
Contract, quote or invoice
Guarantee certificate
Any letter from Ofgem or TrustMark, including your Unique Measure Reference Number
Emails and letters with the installer

If paperwork is missing

Don't know who installed ECO work: Ofgem accepts subject access requests at ECO.SAR@ofgem.gov.uk, with two proofs of address
Missing guarantee for work since 1 January 2020: TrustMark, info@trustmark.org.uk
Cavity wall guarantee: CIGA, guarantees@ciga.co.uk, with proof of ownership

Evidence of the problem

Dated photos of damp, mould or damage
A timeline of when it started and what you reported
Any independent survey report
Repair quotes, if you have them

Be wary of anyone charging to "handle your claim"

The Find & Fix audit, TrustMark's complaints process, CIGA's concern process and the Dispute Resolution Ombudsman are all free to use yourself. CIGA says it does not cold call or make unannounced visits, and TrustMark advises not letting anyone in who cannot quote your Unique Measure Reference Number.

Common questions

Sources

Last reviewed September 2026.