Health Risks of Failed External Wall Insulation: Damp and Mould

Failed external wall insulation (EWI) can let water into walls and lead to damp and mould inside the home. This page summarises what official UK guidance says about the health risks, who is most at risk, and where to get help. It is general information, not medical advice.

If you are worried about someone's health

Call 999 in a medical emergency, such as severe difficulty breathing. For medical help that is not an emergency, call NHS 111 or speak to your GP, and tell them about the damp or mould at home.

What the Guidance Says About Damp and Mould

Health effects

Guidance published by the Ministry of Housing, Communities and Local Government, the Department of Health and Social Care and the UK Health Security Agency says damp and mould mainly affect the airways and lungs, but can affect health in other ways too.

Respiratory:

• Cough, wheeze and shortness of breath
• Developing or worsening asthma
• Rhinitis (blocked or runny nose, sneezing, itching)
• Airway infections
• Worsening of conditions such as bronchitis and COPD

Other effects:

• Eye irritation
• Eczema, itchy skin or rashes
• Other fungal infections
• Poor mental health, for example from living with damp, damaged belongings or delays to repairs

Do not wait to identify the type of mould

The official guidance does not single out 'black mould' or 'toxic mould'. It treats damp and mould as something to address promptly, and says removing surface mould alone will not stop it coming back if the cause is not fixed.

Who is at greater risk?

The guidance lists people who are more vulnerable to the health effects:

Children and young people
Older people
People with existing conditions such as allergies, asthma, COPD, cystic fibrosis, or lung or heart disease
People with weakened immune systems, for example during cancer treatment, after a transplant or on immunosuppressant medicines
People with mental health conditions
Pregnant women and people who have recently given birth
People who are bedbound, housebound or have limited mobility

When to Seek Medical Help

Call 999 or go to A&E in an emergency, for example:

•Severe difficulty breathing
•An asthma attack where the reliever inhaler is not helping
•Chest pain

Call NHS 111 or speak to your GP if:

•You have a cough, wheeze or breathlessness that is not going away
•Asthma or another lung condition is getting harder to control
•You keep getting chest or sinus infections
•You have skin rashes or eye irritation you think are linked to your home
•You are worried about any symptoms

Useful to tell the doctor:

1. That there is damp or mould at home, and where
2. Roughly when it started, and when symptoms started
3. Whether symptoms ease when you are away from home

Reducing Exposure While You Wait for Repairs

These steps can help while the cause is being investigated, but they do not fix a moisture problem in the wall:

Day to day:

Ventilate: Open windows when you can and use extractor fans when cooking or bathing.
Wipe condensation: Dry windows and sills so water does not sit there.
Small patches of mould: The guidance says use a mould and mildew cleaner rather than bleach, and wear a mask, gloves and goggles.
Photograph first: Take dated photos before cleaning so there is a record.

Bigger problems:

Larger areas of mould: The guidance says these should be dealt with by qualified professionals.
Use rooms carefully: If one room is badly affected, avoid sleeping in it where you can, especially for people at greater risk.
Do not paint over mould or block vents and trickle vents.
Get the cause fixed: See the routes below.

Cleaning is not a fix

The guidance is clear that removing surface mould will not stop it returning. If water is getting through failed external wall insulation, the insulation itself needs to be inspected and put right.

Getting the Cause Fixed If You Own Your Home

If your external wall insulation was installed under ECO4 or the Great British Insulation Scheme, TrustMark offers a free Find & Fix audit, and if faults are found you should not be asked to pay for repairs. Contact TrustMark on 0333 555 1234 (option 1) or onsitebookings@trustmark.org.uk. The National Audit Office found 6% of homes with scheme-funded external wall insulation had health and safety risks needing immediate correction, such as inadequate ventilation, so tell TrustMark if anyone in the home is unwell.

For internal wall insulation under these schemes, contact Ofgem's ECO contact centre on 0808 169 4447 or ECOhelp@ofgem.gov.uk.

There is no government compensation scheme. The scheme guarantees pay for repairs, not for ill health, damaged belongings or loss of earnings. If you think you have a claim for those, get independent legal advice, for example through Citizens Advice (consumer helpline 0808 223 1133).

How the free audit works

If You Rent Your Home (England)

1.
Tell your landlord in writing
Describe the damp or mould, where it is and when it started, and keep a copy with dated photos.
2.
Social housing: Awaab's Law
Since 27 October 2025, social landlords must investigate significant damp and mould hazards within 10 working days and make emergency hazards safe within 24 hours. Awaab's Law applies to social housing only; it does not cover owner-occupiers, and its extension to private renting has no start date yet.
3.
Private renting: your council
If the problem is serious and your landlord does not deal with it, you can ask your council's environmental health team to inspect. Councils assess hazards using the Housing Health and Safety Rating System, which was revised from 23 June 2026; damp and mould growth remains one of the hazards it covers.

For advice on your situation, contact Citizens Advice or Shelter's damp and mould advice.

Worried Failed EWI Is Affecting Your Home?

ECO4 or GBIS external wall insulation: start with the free Find & Fix audit. If no free route covers your home, we can introduce you to a specialist through Better Home Hub. Sending an enquiry is free; any survey or work is agreed and paid for between you and the specialist.

The free audit route Ask for a specialist

Sources

Last reviewed September 2026.