Cavity wall insulation guarantees explained

A cavity insulation guarantee, such as the 25-year guarantee from the Cavity Insulation Guarantee Agency (CIGA), covers defects in materials and workmanship. It passes to later owners, but can be invalidated if the insulation is altered or disturbed.

By the Cavity Wall Insulation UK editorial team · checked against the official sources below · last reviewed 19 October 2026

Old cavity insulation drill holes, filled with mortar, spaced across a brick wall

What CIGA covers

CIGA says its guarantee covers defects in materials or workmanship, with claims notified within 25 years of installation, and that it investigates and rectifies defects free of charge up to a current maximum of £20,000 for rectification work.

How to claim

Report the problem to the original installer as soon as you can.
If it is not resolved satisfactorily within two months, tell CIGA.
Do not disturb the insulation yourself; that can invalidate the guarantee.
Keep photos and dates of the problem and any correspondence.

Lost the paperwork?

CIGA can confirm cover and issue a duplicate guarantee, currently £60 including VAT, with two proof-of-ownership documents.

What our quotes say

We name the registered installer and the guarantee that will be issued, and by whom, on your quote before you book. If a job cannot carry an independent guarantee, we tell you first.

Related services

Sources: CIGA: the CIGA guarantee.

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