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2025 UK EWI Crisis: What Homeowners Must Know About Botched Installations

Last modified: 03.12.2025
2025 UK EWI Crisis: What Homeowners Must Know About Botched Installations

External Wall Insulation (EWI) failures increased severely early 2025 within the UK. Many homes that were supposed to receive a simple energy-saving upgrade instead suffered from structural problems, damp, mould and cracked render.

The push to meet ECO 4 deadlines was a significant reason for these EWI failures. It was revealed that some installers worked too fast, used the wrong materials and/or skipped essential steps, prioritising speed over quality. The consequences were extremely serious as many homeowners are still dealing with faulty wall insulation that needs repair or full removal.

The 2025 EWI scandal serves as an essential lesson for many. Insulation should never be done carelessly; care and quality are necessities. It will be expensive and stressful to fix. Knowing what went wrong, as well as what to look out for, will help you to protect your home

A clear pattern often follows poor installations. The most common UK EWI failures seen today are as follows:

Early failure is caused when installers apply insulation over cracked, damp, or unstable walls. If the wall is unhealthy, the insulation will not attach properly and will fail.

The boards should be attached correctly or risk shifting, bending or detaching, leading to cracked render and rainwater coming in.

Tightly fitted boards prevent cold patches and seal the insulation system. Condensation and mould can occur when this is not done.

The render is what protects the insulation and gives your home that aesthetically pleasing finished look. When applied too thin and too quickly, it cracks, letting moisture in and damaging the system behind it.

Some installers cover vents or seal areas that should be left open. This traps moisture in the walls and can lead to damp, mould and musty smells.

Insulation can certainly be a mystery for most homeowners. You can see the boards going up, feel the walls, but you rarely know whether the adhesive, fixings or render are being applied correctly. Sometimes this lack of knowledge leaves many homeowners at the mercy of the installers.

Being informed is essential. PAS 2035 is a new British Standard that establishes a quality standard for the retrofit and energy efficiency sector for housing. Learning about this will give homeowners the confidence to ask the right questions and spot problems before it escalates.

EWI PRO offers a comprehensive UK-wide directory of qualified, vetted installers, helping you find the ideal professional for your project. Their approved installers have completed their state-of-the-art training courses, ensuring that they are trained to follow the exact standards and equipped with the latest knowledge of EWI PRO materials and installation methods. For step-by-step demonstrations of installations, materials, fixings, and render applications check out their YouTube Channel here.

Additionally, EWI PRO will train homeowners for free, providing guidance and up-to-date knowledge of the EWI industry and best practices. This helps you to make informed choices about your external wall insulation. Contact EWI PRO on 0800 133 7072 to find out more about this training.  

By taking some time to learn and verify, you’re no longer blindly trusting an installer; instead you can make informed decisions, protect your home and ensure your insulation actually performs.

Externally homeowners can check for cracks, uneven walls, visible board lines or dark marks where water enters. If your external wall insulation is being installed by EWI PRO approved installers, you can take photos at each stage of the installation and send them to EWI PRO for review. They’ll review all the photos to ensure the work is being completed to the highest standard.

Internally it’s important to check for damp patches, mould, peeling wallpaper, draughts, or cold spots.

Check the paperwork from your installers. This includes a survey, material details, warranty and compliance certificate. Missing paperwork is a serious red flag.

EWI PRO’s support is multifaceted, providing surveys, audits, training, on-site guidance and post-completion assessments.

If problems occur EWI Pro can help you:

You can book this with EWI Pro to professionally check for moisture, gaps and cracks in the insulation.

Be sure to gather all paperwork, including your warranty or guarantee information.

Contact the guarantee provider if the installer is unresponsive.

For ECO4 installations contact Ofgem at ECOhelp@ofgem.gov.uk

If you have general complaints follow the TrustMark complaints process

It’s important you make an informed decision with this as some fixes are simple, while others would need a complete reinstall.

The 2025 EWI crisis demonstrated the severe cost of cutting corners which leads to wasted money, stress, and long-term damage. You can find high-quality products here; however, it is the installer who determines the success of the installation. Companies like EWI PRO demonstrate how training of a high calibre, approved materials and careful installations can help to prevent the problems that many UK homeowners are facing today.

Choose quality. Choose to protect your home with EWI PRO.