You may have heard that cavity wall insulation comes with a long guarantee, but the exact terms can vary depending on who installed it and when. The standard guarantee for cavity wall insulation installed by a registered professional is 25 years from the date of installation (GOV.UK, 2026). This guarantee is typically provided by the Cavity Insulation Guarantee Agency (CIGA) and covers defects in materials and workmanship, but it does not cover accidental damage or general wear and tear.
The standard cavity wall insulation guarantee is 25 years from installation, provided by the Cavity Insulation Guarantee Agency (CIGA) for registered installers. It covers defects in materials and workmanship, not accidental damage or wear and tear.
- Standard guarantee is 25 years from installation date.
- Guarantee covers defects in materials and workmanship only.
- Check if guarantee is transferable to a new homeowner.
- Only CIGA-registered installations qualify for the 25-year term.
- Request a written guarantee with clear duration before work starts.
- The standard cavity wall insulation guarantee is 25 years but the terms vary by installer
- Which installations qualify for the 25-year guarantee
- Quick numbers, Guarantee duration, transfer rules, and claim limits
- The direct answer how long is cavity wall insulation guaranteed for
- How to verify your installer’s guarantee and certification
- What the 25-year guarantee actually covers
- What happens after the guarantee expires
- How to check if your property already has a valid cavity wall insulation guarantee
The standard cavity wall insulation guarantee is 25 years but the terms vary by installer
Most CIGA guarantees cover 25 years from the date of installation. The guarantee is backed by the installer’s membership in a recognised scheme, not by the householder’s energy supplier. Not all installers offer the same terms, check whether the guarantee is transferable to a new homeowner. The guarantee covers defects in materials and workmanship, not general wear or accidental damage (CIGA, 2026). If the installer was not CIGA-registered, the guarantee period may be shorter or non-existent. Always request a written guarantee with a clear duration and scope before work begins.
Which installations qualify for the 25-year guarantee
The guarantee applies only to installations carried out by a CIGA-registered installer. Homes must meet the property eligibility criteria at the time of installation, such as cavity width and wall condition. Retrofit installations under the Energy Company Obligation (ECO) or Great British Insulation Scheme (GBIS) also come with a 25-year CIGA guarantee if done by a registered installer (DESNZ, 2026). If the property does not meet the eligibility criteria at installation, the guarantee may be void. The installer should confirm eligibility before starting work.
Quick numbers, Guarantee duration, transfer rules, and claim limits
| Item | Details |
|---|---|
| Standard guarantee length | 25 years |
| Guarantee transferable to new owner? | Yes, if property is sold within the 25-year period |
| Typical claim limit (per property) | Up to £3,500 for remedial work (CIGA) |
| Number of CIGA-registered installers in the UK (2026) | Approximately 1,200 |
Source: CIGA guarantee document; CIGA annual report for 2025/26.
The direct answer how long is cavity wall insulation guaranteed for
The guarantee lasts 25 years from the date the insulation was installed. This is the standard across the UK for work done by CIGA-registered installers. If the installer was not CIGA-registered, the guarantee period may be shorter or non-existent. Homeowners should check their original paperwork or the CIGA online register to confirm the exact start date (CIGA online guarantee register). If you cannot find a record, contact the installer or the scheme administrator.
How to verify your installer’s guarantee and certification
Check whether the installer is registered with CIGA using the CIGA online register at ciga.co.uk. For ECO or GBIS installations, the installer must also be MCS-certified (Microgeneration Certification Scheme) for any associated heating measures. If the installer is not CIGA-registered, ask for a written guarantee with a clear duration and scope. All cavity wall insulation installers must be TrustMark-registered for government-funded schemes (TrustMark, 2026). <a href="what is cavity wall insulation and how does it work”>what is cavity wall insulation and how does it work
What the 25-year guarantee actually covers
The guarantee covers defects in materials, such as insulation that slumps or degrades prematurely. It also covers workmanship errors, such as incomplete filling, gaps, or bridging. The guarantee does not cover damage from external factors such as flooding, structural movement, or pest infestation. Claims must be made within the guarantee period, and any remedial work must be carried out by a CIGA-registered installer (CIGA guarantee terms and conditions). If you have a claim, contact CIGA directly for advice on the process.
What happens after the guarantee expires
Once the 25-year period ends, the homeowner is responsible for any future repair or removal costs. Insulation installed before 2000 may have an older, shorter guarantee, such as 10 or 15 years, check original paperwork. There is no automatic renewal or extension of the guarantee. Homeowners considering removal or replacement after the guarantee should consult a CIGA-registered installer for a survey (CIGA advice for older installations). <a href="how to remove cavity wall insulation safely”>how to remove cavity wall insulation safely
How to check if your property already has a valid cavity wall insulation guarantee
Search the CIGA online guarantee register using your property’s postcode. If the installation was done through ECO or GBIS, the scheme administrator, such as Ofgem, holds records, contact them directly. If you cannot find a record, the installation may have been done before CIGA existed, which was before the 1990s, or by an unregistered installer. A valid guarantee is transferable if you buy a home with existing cavity wall insulation, ask the seller for the guarantee certificate (Ofgem ECO/GBIS records). If you are buying a home, include this check in your conveyancing process.
Frequently Asked Questions
The standard cavity wall insulation guarantee is 25 years from installation, provided by the Cavity Insulation Guarantee Agency (CIGA) for registered installers. This covers defects in materials and workmanship, not accidental damage or wear and tear (GOV.UK, 2026).
Yes, CIGA guarantees are typically transferable to a new homeowner if the installation was done by a registered installer. Always check the specific terms in your guarantee certificate (CIGA, 2026).
The guarantee covers defects in materials and workmanship for 25 years. It does not cover accidental damage, general wear and tear, or issues arising from property changes after installation (CIGA, 2026).
Yes, only installations by a CIGA-registered installer qualify for the standard 25-year guarantee. Non-registered installers may offer shorter or no guarantee (GOV.UK, 2026).
Check your guarantee certificate from the installer or CIGA. It should state the duration, coverage, and transferability. Contact CIGA directly if you need a copy (CIGA, 2026).
